originals - Revista Nefrologia
Transcripción
originals - Revista Nefrologia
Included in ISI-WOK, MEDLINE, EMBASE, IME, IBECS, SCIELO V o l u m e 3 4 - N u m b e r 4 - 2 0 1 4 Tyrosine kinase receptor Nephrin CD2AP Growth Factors PIP2 PIP3 PI3K PDK1 mTOR2-Rictor p -Thr308 p -Ser473 Akt mTOR inhibitors mTOR inhibitors Rac1 Cytoskeletal reorganisation GLUT-4 translocation TSC1-TSC2 Raptor-mTOR1 GSK3 FOXO Gluconeogenesis Degradation of lipids Protein synthesis Protein synthesis Stimulation Estimulación Pro-apoptotic factors Cell cycle inhibition Cell cycle maintenance Cell cycle and Apoptosis Blocking/Inhibition Bloqueo/inhibición Canaud et al. Nad Med 2013 Canaud et al. Nad Med 2013 Metabolism Podocyte-specific Específico de podocitos mTOR INHIBITION AND AKT PROTEINS HIDDEN SOURCES OF PHOSPHORUS TREATING HYPONATRAEMIA ASSOCIATED WITH THE SYNDROME OF INAPPROPRIATE ADH HYPERSECRETION ANTIBODIES AGAINST THE M-TYPE PHOSPHOLIPASE A2 RECEPTOR IN MEMBRANOUS GN TREATED WITH TACROLIMUS Official Publication of the Spanish Society of Nephrology Full version in English and Spanish at www.revistanefrologia.com Revista Nefrología Editor-in-Chief: Mariano Rodríguez Portillo Executive editor of digital Nefrología: Roberto Alcázar Arroyo Deputy editors: Andrés Purroy Unanua, Ángel Luis Martín de Francisco, Fernando García López, Víctor Lorenzo Sellares, Vicente Barrio Lucia Honorary editors: Luis Hernando Avendaño, David Kerr, Rafael Matesanz Acedos Carlos Quereda Rodríguez-Navarro Subject editors (editors of thematic areas) Experimental Nephrology A. Ortiz* J. Egido de los Ríos S. Lamas J.M. López Novoa D. Rodríguez Puyol J.M. Cruzado Clinical Nephrology M. Praga* J. Ara J. Ballarín G. Fernández Juárez F. Rivera A. Segarra Diabetic Nephropathy F. de Álvaro* J.L. Górriz A. Martínez Castelao J.F. Navarro J.A. Sánchez Tornero R. Romero Hereditary Nephropathies R. Torra* J.C. Rodríguez Pérez E. Coto V. García Nieto Chronic Kidney Disease A.L. Martín de Francisco* A. Otero E. González Parra I. Martínez J. Portolés Pérez CRF-Ca/P Metabolism E. Fernández* J. Cannata Andía R. Pérez García M. Rodríguez J.V. Torregrosa Arterial Hypertension R. Marín* L. Orte R. Santamaría A. Rodríguez Jornet Nephropathy and Cardiovascular Risk J. Díez* A. Cases J. Luño Quality in Nephrology M.D. Arenas E. Parra Moncasi P. Rebollo F. Ortega Acute Renal Failure F. Liaño* F.J. Gainza J. Lavilla E. Poch Peritoneal Dialysis R. Selgas* M. Pérez Fontán C. Remón M.E. Rivera Gorrin G. del Peso Haemodialysis A. Martín Malo* P. Aljama F. Maduell J.A. Herrero J.M. López Gómez J.L. Teruel Renal Transplantation J. Pascual* M. Arias J.M. Campistol J.M. Grinyó M.A. Gentil A. Torres Paediatric Nephrology N. Gallego A.M. Sánchez Moreno R. Vilalta Nephropathology J. Blanco* I.M. García E. Vázquez Martul A. Barat Cascante Evidence-Based Nephrology Vicente Barrio* (Director de Suplementos), Fernando García López (Asesor de Metodología). Editores: María Auxiliadora Bajo, José Conde, Joan M. Díaz, Mar Espino, Domingo Hernández, Ana Fernández, Milagros Fernández, Fabián Ortiz, Ana Tato. Continued Training (journal NefroPlus) Andrés Purroy*, R. Marín, J.M. Tabernero, F. Rivera, A. Martín Malo. * Coordinators of thematic area EDITORIAL BOARD A. Alonso J. Arrieta F.J. Borrego D. del Castillo P. Gallar M.A. Frutos A. Mazuecos A. Oliet L. Pallardo J.J. Plaza J. Teixidó J. Alsina J. Bustamente P. García Cosmes M.T. González L. Jiménez del Cerro J. Lloveras B. Miranda J. Olivares A. Serra F.A. Valdés F. Anaya A. Barrientos P. Errasti F. García Martín M. González Molina B. Maceira J. Mora A. Pérez García L. Sánchez Sicilia J. Aranzábal G. Barril F. Caravaca C. de Felipe S. García de Vinuesa A. Gonzalo R. Lauzurica J.F. Macías E. Martín Escobar J.M. Morales R. Peces J.M. Tabernero G. de Arriba C. Bernis E. Fernández Giráldez F.J. Gómez Campderá P. Gómez Fernández E. Huarte R. Marcén J. Montenegro A. Palma L. Piera A. Tejedor INTERNATIONAL COMMITEE BOARD E. Burdmann (Brasil) B. Canaud (Francia) J. Chapman (Australia) R. Coppo (Italia) R. Correa-Rotter (México) F. Cosío (EE. UU.) G. Eknoyan (EE. UU.) A. Felsenfeld (EE. UU.) J.M. Fernández Cean (Uruguay) J. Frazao (Portugal) M. Ketteler (Alemania) Levin, Adeera (Canadá) Li, Philip K.T. (Hong Kong, China) L. Macdougall (Gran Bretaña) P. Massari (Argentina) SUBSCRIPTIONS, ADVERTISING AND PUBLISHING S. Mezzano (Chile) B. Rodríguez Iturbe (Venezuela) C. Ronco (Italia) J. Silver (Israel) P. Stevinkel (Suecia) A. Wiecek (Polonia) C. Zoccali (Italia) COUNCIL OF THE SPANISH SOCIETY OF NEPHROLOGY President: Dr. D. Alberto Martínez Castelao Director of Nefrología Publishing Group: Dr. D. Mariano Rodríguez Portillo Vice-president: Dra. D.ª Isabel Martínez Secretary: Dr. D. José Luis Górriz Chairperson of the Dialysis and Transplantation Registry: Dr. D. Ramón Saracho • ISSN: 2013-2514 Treasurer: Dra. D.ª María Dolores del Pino and Research: Rambla del Celler 117-119, 08190 Sant Cugat del Vallès. Barcelona Tel. 93 589 62 64 - Fax. 93 589 50 77 © Sociedad Española de Nefrología 2014. All international rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, mechanical, electronic, photocopying, recording or otherwise, without the prior written permission of the publisher. Ordinary members: Dra. D.ª Gema Fernández Fresnedo Dra. D.ª Elvira Fernández Giráldez Dr. D. Julio Pascual Dr. D. José María Portolés Distribuido por: EUROMEDICE, Ediciones Médicas, S.L. Nefrologia is distributed exclusively among medical professionals. Information and subscriptions: S.E.N. Secretary: [email protected] Tel: 902 929 210 Queries regarding of manuscripts: [email protected] © Copyright 2014. Grupo Editorial Nefrología. All rights reserved. Avda. dels Vents 9-13, Esc. B, 2.º 1.ª Edificio Blurbis 08917 Badalona Tel. 902 02 09 07 - Fax. 93 395 09 95 Web nefrología: E-mail Dirección Editorial: Chairpersons of Education Dr. D. Juan Francisco Navarro Dr. D. Josep Maria Cruzado Chairperson for selection of the S.E.N. Congress presentations Dra. D.ª Rosa Sánchez Hernández Direcciones de interés: www.revistanefrologia.com [email protected] contents Included in ISI-WOK, MEDLINE, EMBASE, IME, IBECS, SCIELO Included in ISI-WOK, MEDLINE, EMBASE, IME, IBECS, SCIELO V o l u m e 3 4 - N u m b e r 4 - 2 0 1 4 CD2AP 4 - 2 014 Nephrin Vo l u m e 3 4 - N u m b e r Tyrosine kinase receptor Growth Factors PIP2 PIP3 PI3K PDK1 mTOR2-Rictor p -Thr308 mTOR inhibitors EDITORIAL COMMENT mTOR inhibition, Akt proteins and chronic kidney disease Eva Márquez, Julio Pascual Rac1 Cytoskeletal reorganisation GLUT-4 translocation TSC1-TSC2 Raptor-mTOR1 GSK3 FOXO Gluconeogenesis Degradation of lipids Protein synthesis Pro-apoptotic factors Protein synthesis Stimulation Estimulación 425 • mTOR inhibitors p -Ser473 Akt Cell cycle inhibition Cell cycle maintenance Cell cycle and Apoptosis Blocking/Inhibition Bloqueo/inhibición Canaud et al. Nad Med 2013 Canaud et al. Nad Med 2013 Metabolism Podocyte-specific Específico de podocitos MTOR INHIBITION AND AKT PROTEINS HIDDEN SOURCES OF PHOSPHORUS TREATING HYPONATRAEMIA ASSOCIATED WITH THE SYNDROME OF INAPPROPRIATE ADH HYPERSECRETION ANTIBODIES AGAINST THE M-TYPE PHOSPHOLIPASE A2 RECEPTOR IN MEMBRANOUS GN TREATED WITH TACROLIMUS Official Publication of the Spanish Society of Nephrology SHORT REVIEW 428 • Renal function, nephrogenic systemic fibrosis and other adverse reactions associated with gadolinium-based contrast media Ana Canga, Maria Kislikova, María Martínez-Gálvez, Mercedes Arias, Patricia Fraga-Rivas, Cecilio Poyatos, Ángel L.M. de Francisco Full version in English and Spanish at www.revistanefrologia.com COVER IMAGES See page 426 of this issue, Nefrologia 2014;34(4):425-7. Schematic and simplified view of Akt action pathways. SPECIAL ARTICLE 439 • Treatment of hyponatremia induced by the syndrome of inappropriate antidiuretic hormone secretion: a multidisciplinary algorithm Isabelle Runkle, Carles Villabona, Andrés Navarro, Antonio Pose, Francesc Formiga, Alberto Tejedor, Esteban Poch ORIGINALS 451 • Predictive factors for kidney damage in febrile urinary tract infection. Usefulness of procalcitonin Elena Lucas-Sáez, Susana Ferrando-Monleón, Juan Marín-Serra, Ricardo Bou-Monterde, Jaime Fons-Moreno, Amelia Peris-Vidal, Aurelio Hervás-Andrés 458 • Cost analysis and sociocultural profile of kidney patients. Impact of the treatment method Víctor Lorenzo-Sellares, M. Inmaculada Pedrosa, Balbina Santana-Expósito, Zoraida García-González, Mónica Barroso-Montesinos 469 • During the pre-dialysis stage of chronic kidney disease, which treatment is associated with better survival in dialysis? Francisco Caravaca, Raúl Alvarado, Guadalupe García-Pino, Rocío Martínez-Gallardo, Enrique Luna 477 • Fluid therapy and iatrogenic hyponatraemia risk in children hospitalised with acute gastroenteritis: prospective study Marciano Sánchez-Bayle, Raquel Martín-Martín, Julia Cano-Fernández, Enrique Villalobos-Pinto 483 • Soy protein and genistein improves renal antioxidant status in experimental nephrotic syndrome Mohammad H. Javanbakht, Reza Sadria, Mahmoud Djalali, Hoda Derakhshanian, Payam Hosseinzadeh, Mahnaz Zarei, Gholamreza Azizi, Reza Sedaghat, Abbas Mirshafiey 491 • Evolution of antibody titre against the M-type phospholipase A2 receptor and clinical response in idiopathic membranous nephropathy patients treated with tacrolimus Alfons Segarra-Medrano, Elías Jatem-Escalante, Clara Carnicer-Cáceres, Irene Agraz-Pamplona, M. Teresa Salcedo, Naiara Valtierra, Elena Ostos-Roldán, Karla V. Arredondo, Juliana Jaramillo SHORT ORIGINAL 498 • Sumario_03.indd 3 Hidden sources of phosphorus: presence of phosphorus-containing additives in processed foods Luis M. Lou-Arnal, Laura Arnaudas-Casanova, Alberto Caverni-Muñoz, Antonio Vercet-Tormo, Rocío Caramelo-Gutiérrez, Paula Munguía-Navarro, Belén Campos-Gutiérrez, Mercedes García-Mena, Belén Moragrera, Rosario Moreno-López, Sara Bielsa-Gracia, Marta Cuberes-Izquierdo, Grupo de Investigación ERC Aragón 09/07/14 12:31 contents Included in ISI-WOK, MEDLINE, EMBASE, IME, IBECS, SCIELO Vo l u m e 3 4 - N u m b e r 4 - 2 014 REVIEW 507 • Defining protein-energy wasting syndrome in chronic kidney disease: prevalence and clinical implications Carolina Gracia-Iguacel, Emilio González-Parra, Guillermina Barril-Cuadrado, Rosa Sánchez, Jesús Egido, Alberto Ortiz-Arduán, Juan J. Carrero CLINICAL CASE 520 • Hypersensitivity reactions to synthetic haemodialysis membranes Rafael J. Sánchez-Villanueva, Elena González, Santiago Quirce, Raquel Díaz, Laura Álvarez, David Menéndez, Lucía Rodríguez-Gayo, M. Auxiliadora Bajo, Rafael Selgas LETTERS TO THE EDITOR A) Comments on published articles 526 • Comment on “Kaposi´s sarcoma in the early post-transplant period in a kidney transplant recipient” Francisco Coronel, Manuel Macía 526 • Increase of ischaemic colitis incidence in haemodialysis Borja Quiroga B) Brief papers on research and clinical experiments 528 • Home haemodialysis: a right and a duty Alejandro Pérez-Alba, J. Ramón Pons-Prades, Esther Tamarit-Antequera, Juan J. Sánchez-Canel, Vicente Cerrillo-García, Elena Renau-Ortells, Laura Salvetti, M. Ángeles Fenollosa-Segarra 530 • Influence of glucose solutions on the development of hyperglycaemia in peritoneal dialysis. Behaviour of glycated haemoglobin and the lipid profile Margarita Delgado-Córdova, Francisco Coronel, Fernando Hadah, Secundino Cigarrán, J. Antonio Herrero-Calvo 531 • Results 5 years after living donor renal transplantation without calcineurin inhibitors Gustavo Martínez-Mier, Sandro F. Ávila-Pardo, Marco T. Méndez-López, Luis F. Budar-Fernández, Benjamín Franco-Ahumada, Felipe González-Velázquez C) Brief case report 534 • Hepatitis C virus infection, interferon α and lupus; a curious combination Pilar Auñón-Rubio, Eduardo Hernández-Martínez, Ángel Sevillano-Prieto, Enrique Morales-Ruiz 536 • Baclofen neurotoxicity in a patient with end-stage chronic renal failure Pablo Justo-Ávila, Luciemne Fernández-Antuña, M. Teresa Compte-Jove, Cristina Gállego-Gil 538 • Achromobacter xylosoxidans in two haemodialysis patients M. Eugenia Palacios-Gómez, Adoración Martín-Gómez, Sergio García-Marcos 539 • Methylmalonic acidemia with homocystinuria. A very rare cause of kidney failure in the neonatal period Orlando Mesa-Medina, Mónica Ruiz-Pons, Víctor García-Nieto, José León-González, Santiago López-Mendoza, Carlos Solís-Reyes 540 • An uncommon cause of linfadenopathy in a kidney transplant patient: Cat-scratch disease Cláudia Bento, La Salete Martins, André Coelho, Manuela Almeida, Sofia Pedroso, Leonídeo Dias, Ramon Vizcaíno, António Castro-Henriques, António Cabrita 542 • Extreme hypocalcaemia and hyperparathyroidism following denosumab. Is this drug safe in chronic kidney disease? Ana E. Sirvent, Ricardo Enríquez, María Sánchez, César González, Isabel Millán, Francisco Amorós Sumario_03.indd 4 09/07/14 12:31 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society editorial comment mTOR inhibition, AKT proteins and chronic kidney disease Eva Márquez, Julio Pascual Servicio de Nefrología. Hospital del Mar. Institut Mar d’Investigacions Mediques. Red Temática de Investigación Renal (RedinRen). Barcelona (Spain) Nefrologia 2014;34(4):425-7 doi:10.3265/Nefrologia.pre2014.Apr.12381 D espite up to 9 % of the population suffering from some degree of chronic kidney disease (CKD), the physiopathological pathways that participate in the disease’s progression are still unknown in detail1. Podocytes, highly specialised glomerular epithelial cells, play an essential role in maintaining the glomerular filtration barrier. Precise regulation of actin cytoskeleton is necessary for this maintenance; its reorganisation produces functional and morphological alterations that cause proteinuria. The Akt protein family are serine/threonine kinases that regulate metabolic, growth and cell survival factors (Figure 1)2. Podocytes have a protective role against apoptosis3-6. Nephrin and CD2AP, essential for maintaining cell structure and function, play a role in the regulation of cell apoptosis7 and a possible function in the regulation of cytoskeleton8, both Akt effects. Canaud et al. have recently published the results of a study in which they demonstrate, using experimental in vivo, in vitro models and human biopsies, Akt2 activation as a protective mechanism in the podocyte against a reduction of kidney mass9. The loss of Akt2 or the decrease in one of the phosphorylations required for its activity [pAkt (Ser473)] worsens podocyte injury, causing proteinuria. A failure in its phosphorylation, blocking the mTOR2 complex by sirolimus, could explain, at least in part, the undesirable effects of this drug group observed in some transplant patients. This study stands out methodologically for the use of genetically engineered animals. Its authors created knockout (KO) animals for Akt2 and podocyte-specific KO, enabling Correspondence: Julio Pascual Servicio de Nefrología. Hospital del Mar. Institut Mar d’Investigacions Mediques. Red Temática de Investigación Renal (RedinRen). 08003 Barcelona. (Spain). [email protected] the evaluation of these cells’ significance in the evolution of renal lesions. These animals, together with their respective and suitable controls, are subjected to a reduction of kidney mass through subtotal nephrectomy or assessed at 13 months old as an ageing model. Similarly, they develop a KO-specific mouse for Rictor, an essential component of the mTOR2 complex. An increase in Akt2 protein level, primarily present at a podocyte level, is observed in the reduction of kidney mass. Its increase seems to be a protective mechanism against damage, since, in relation to their respective controls, the KO animals for Akt2 show podocyte injury with pedicel effacement associated with an increase in Rac1, increase in apoptosis at a glomerular level, higher degree of glomerular lesion and as a result, higher albumin level. Similar alterations are found in KO mice for Akt 2 specifically in the podocytes, which confirms the significance of podocyte Akt2 in renal function maintenance. However, not only the absence of Akt2 causes renal alterations: phosphorylation deficiency, as that observed in KO mice for Rictor, causes equivalent alterations. The in vitro results reinforce the in vivo findings. KO podocytes for Akt2 or treated with sirolimus show alteration of its cytoskeleton with redistribution of actin fibres and appearance of adhesion foci. The studies carried out on human biopsies show, in the same way as in the animal model, that Akt2 is mainly expressed in podocytes. An increase of pAkt (Ser473) is also observed at a glomerular level in patients with various pathologies, mainly of vascular origin. The study of transplant patients with different degrees of renal dysfunction shows that only patients with severe nephron reduction present proteinuria when undergoing treatment with sirolimus. Patients with worse renal function show intense stains for pAkt (Ser473) and Rictor; this is not the case for patients with worse renal function being 425 Eva Márquez et al. AKT in chronic kidney disease editorial comment Tyrosine kinase receptor Nephrin CD2AP Growth Factors PIP2 PI3K PIP3 PDK1 mTOR2-Rictor p -Thr308 p -Ser473 Akt Rac1 Cytoskeletal reorganisation GLUT-4 translocation TSC1-TSC2 mTOR inhibitors mTOR inhibitors Raptor-mTOR1 GSK3 FOXO Gluconeogenesis Degradation of lipids Protein synthesis Pro-apoptotic factors Protein synthesis Stimulation Cell cycle inhibition Cell cycle maintenance Cell cycle and Apoptosis Blocking/Inhibition Canaud et al. Nad Med 2013 Metabolism Podocyte-specific Figure 1. Schematic and simplified view of Akt action pathways treated with sirolimus. This group shows greater cell apoptosis at a glomerular level and, clinically, the presence of proteinuria. One of the most noteworthy findings is the correlation in time between sirolimus withdrawal, increase of pAkt (Ser473) in renal biopsy and reduction of proteinuria. With an excellent design in the in vivo and in vitro studies, this study identifies Akt2 as the central element in the pathophysiology of podocyte injury in CKD. Severe nephron reduction models were used, making the findings potentially applicable to CKD of any aetiology. It was recently demonstrated that the activation of Rac1 causes alterations of podocyte cytoskeleton, leading to pedicel effacement10. Canaud et al. showed that Akt2 reduction activates Rac1 causing cytoskeletal alterations. firmed11,12. In addition, from the study by Canaud et al., it can be concluded that there is another kinase, aside from mTOR2, that phosphorylates Akt, since pAkt (Ser473) is not totally absent in the KO model for Rictor. Akt analysis is carried out through studies of total Akt, its isoforms and pAkt (Ser473); however no study was undertaken on the status of specifically Akt2 nor pAkt (Thr308) phosphorylation, which, although not dependent on the mTOR2 complex, would supply relevant information for the complete evaluation of the functional status of Akt13. In addition, the valuation of Rictor-mTOR2 in the various animal models could contribute to clarifying its role and regulation. Surprisingly, in presence of sirolimus, modifications in molecules phosphorylated by the mTOR1 complex, not specifically studied, were not detected. In this way, previous studies on podocytes and on other experimental models which show that mTOR inhibitors do not only block mTOR1, but also mTOR2, are reaf- One of the most remarkable findings is that the defect in Akt phosphorylation seems to explain, at least in part, the development of proteinuria observed in transplant patients 426 Nefrologia 2014;34(4):425-7 Eva Márquez et al. AKT in chronic kidney disease with poor renal function when an mTOR inhibitor is introduced 14. The patients were grouped into high and low estimated glomerular filtration rate; renal function and proteinuria prior to sirolimus introduction or duration of treatment with sirolimus, data which would help to establish the possible predictive role of Akt on renal function following the onset of treatment, were not explained. Studies on human renal biopsies show an increase in glomerular pAkt (Ser473) in various pathologies, but the Akt2 isoform was not specifically studied in any of the groups, which would obviously be of interest in the context of the present study. Future research, in both animal and cell models, should be directed at determining which are the stimuli causing the elevation of Akt2, which could be specific to different pathologies. This aforementioned study focused on established renal damage models, but the study of this pathway in models with early damage would be significant. The prevalence of diabetic nephropathy and the role of the PI3K/Akt pathway in its pathophysiology, including podocyte injury 3-6, make it a clear objective for furthering analysis of the role of Akt2. In addition, in-depth research on apoptosis mechanisms, regulation of the cell cycle (especially in the podocyte, terminally differentiated cell) and modifications of cytoskeleton, all regulated by Akt, is necessary to understand the pathophysiological consequences of the changes in this molecule. In-depth research in these different fields would facilitate the ability to define possible therapeutic targets which would lead to the design of new drugs or the use of current drugs to stop, or even prevent, the development of established renal damage. Finally, findings in human biopsies open the door to new clinical decision-making tools in the management of immunosuppression. With specifically designed studies, it would be possible to confirm the probable prognostic value of total Akt, its phosphorylations and its isoforms when assessing post-transplant biopsies as a step prior to converting to mTOR inhibitors. The study of possible non-invasive markers associated with the results of this study would result in an improvement in routine clinical practice. editorial comment REFERENCES 1. Otero A, de Francisco A, Gayoso P, Garcia F, Group ES. Prevalence of chronic renal disease in Spain: results of the EPIRCE study. Nefrologia 2010;30(1):78-86. 2. Manning BD, Cantley LC. AKT/PKB signaling: navigating downstream. Cell 2007;129(7):1261-74. 3. Wang XM, Yao M, Liu SX, Hao J, Liu QJ, Gao F. Interplay between the Notch and PI3K/Akt pathways in high glucose-induced podocyte apoptosis. Am J Physiol Renal Physiol 2014;306:F205-13. 4. Tejada T, Catanuto P, Ijaz A, Santos JV, Xia X, Sanchez P, et al. Failure to phosphorylate AKT in podocytes from mice with early diabetic nephropathy promotes cell death. Kidney Int 2008;73(12):1385-93. 5. Bussolati B, Deregibus MC, Fonsato V, Doublier S, Spatola T, Procida S, et al. Statins prevent oxidized LDL-induced injury of glomerular podocytes by activating the phosphatidylinositol 3-kinase/AKT-signaling pathway. J Am Soc Nephrol 2005;16(7):1936-47. 6. Logar CM, Brinkkoetter PT, Krofft RD, Pippin JW, Shankland SJ. Darbepoetin alfa protects podocytes from apoptosis in vitro and in vivo. Kidney Int 2007;72(4):489-98. 7. Huber TB, Hartleben B, Kim J, Schmidts M, Schermer B, Keil A, et al. Nephrin and CD2AP associate with phosphoinositide 3-OH kinase and stimulate AKT-dependent signaling. Mol Cell Biol 2003;23(14):4917-28. 8. Zhu J, Sun N, Aoudjit L, Li H, Kawachi H, Lemay S, et al. Nephrin mediates actin reorganization via phosphoinositide 3-kinase in podocytes. Kidney Int 2008;73(5):556-66. 9. Canaud G, Bienaime F, Viau A, Treins C, Baron W, Nguyen C, et al. AKT2 is essential to maintain podocyte viability and function during chronic kidney disease. Nat Med 2013;19(10):1288-96. 10. Yu H, Suleiman H, Kim AH, Miner JH, Dani A, Shaw AS, et al. Rac1 activation in podocytes induces rapid foot process effacement and proteinuria. Mol Cell Biol 2013;33(23):4755-64. 11. Vollenbroker B, George B, Wolfgart M, Saleem MA, Pavenstadt H, Weide T. mTOR regulates expression of slit diaphragm proteins and cytoskeleton structure in podocytes. Am J Physiol Renal Physiol 2009;296(2):F418-26. 12. Lamming DW, Ye L, Katajisto P, Goncalves MD, Saitoh M, Stevens DM, et al. Rapamycin-induced insulin resistance is mediated by mTORC2 loss and uncoupled from longevity. Science 2012;335(6076):1638-43. 13. Song G, Ouyang G, Bao S. The activation of Akt/PKB signaling pathway and cell survival. J Cell Mol Med 2005;9(1):59-71. 14.Diekmann F, Budde K, Oppenheimer F, Fritsche L, Neumayer HH, Campistol JM. Predictors of success in conversion from calcineurin inhibitor to sirolimus in chronic allograft dysfunction. Am J Transplant 2004;4(11):1869-75. Sent to review: 30 Nov. 2013 | Accepted: 21 Apr. 2014 Nefrologia 2014;34(4):425-7 427 short review http://www.revistanefrologia.com © 2014 Revista Nefrología. Órgano Oficial de la Sociedad Española de Nefrología Renal function, nephrogenic systemic fibrosis and other adverse reactions associated with gadolinium-based contrast media Ana Canga1, Maria Kislikova2, María Martínez-Gálvez3, Mercedes Arias4, Patricia Fraga-Rivas5, Cecilio Poyatos6, Ángel L.M. de Francisco2 1 Servicio de Radiodiagnóstico. Hospital Universitario Marqués de Valdecilla. Santander, Cantabria (Spain); 2 Servicio de Nefrología. Hospital Universitario Marqués de Valdecilla. Santander, Cantabria (Spain); 3 Servicio de Radiodiagnóstico. Hospital José María Morales Meseguer. Murcia (Spain); 4 Unidad de Diagnóstico por Imagen Galaria. Empresa Pública de Servicios Sanitarios. Complejo Hospitalario Universitario de Vigo (Spain); 5 Servicio de Radiodiagnóstico. Hospital del Henares. Unidad Central de Radiodiagnóstico. Madrid (Spain); 6 Servicio de Radiodiagnóstico. Hospital Universitario Dr. Peset. Valencia (Spain) Nefrologia 2014;34(4):428-38 doi:10.3265/Nefrologia.pre2014.Apr.12375 ABSTRACT Nephrogenic systemic fibrosis is a fibrosing disorder that affects patients with impaired renal function and is associated with the administration of gadolinium-based contrast media used in MRI. Despite being in a group of drugs that were considered safe, report about this potentially serious adverse reaction was a turning point in the administration guidelines of these contrast media. There has been an attempt to establish safety parameters to identify patients with risk factors of renal failure. The close pharmacovigilance and strict observation of current regulations, with special attention being paid to the value of glomerular filtration, have reduced the published cases involving the use of gadolinium-based contrast media. In a meeting between radiologists and nephrologists we reviewed the most relevant aspects currently and recommendations for its prevention. Keywords: Nephrogenic systemic fibrosis. Gadolinium. Magnetic resonance. Adverse reactions. Función renal, fibrosis sistémica nefrogénica y otras reacciones adversas asociadas a los medios de contraste basados en el gadolinio RESUMEN La fibrosis sistémica nefrogénica es un trastorno fibrosante que afecta a pacientes con deterioro de la función renal y se asocia a la administración de medios de contraste basados en el gadolinio, empleados en la resonancia magnética. A pesar de tratarse de un grupo de fármacos que se consideraban seguros, la notificación de esta reacción adversa, potencialmente grave, supuso un punto de inflexión en las pautas de administración de estos medios de contraste. Se han intentado establecer parámetros de seguridad a fin de identificar a los pacientes con factores de riesgo por presentar insuficiencia renal. La estrecha farmacovigilancia y el rigor en la observación de las normativas actuales, con especial atención al valor del filtrado glomerular, han reducido los casos publicados relacionados con el uso de medios de contraste basados en el gadolinio. En un encuentro entre radiólogos y nefrólogos revisamos los aspectos más relevantes en la actualidad y las recomendaciones para su prevención. Palabras clave: Fibrosis sistémica nefrogénica. Gadolinio. Resonancia magnética. Reacciones adversas. INTRODUCTION Since 1997, when it was reported by Cowper for the first time1, a condition called nephrogenic systemic fibrosis (NSF) Correspondence: Ángel L.M. de Francisco Servicio de Nefrología. Hospital Universitario Marqués de Valdecilla. Avda. Valdecilla, SN. 39008, Santander, Cantabria. (Spain). [email protected] 428 has drawn the attention of nephrologists and radiologists from all over the world. It has been defined as a fibrosing disease that predominantly affects patients who have received gadolinium-based contrasts, with an estimated glomerular filtration rate (GFR) of less than 30ml/min/1.73m2 or those on haemodialysis2,3. In this document, we aim to summarise the clinical expression of NSF, the data known about different gadolinium-based contrasts, the possibilities of identifying Ana Canga et al. Nephrogenic systemic fibrosis patients at risk in order to prevent its onset and the types of treatment for this disease. GADOLINIUM Gadolinium-based contrast media (GBCM) are used in magnetic resonance imaging (MRI) studies due to their magnetic ability to change the position of the protons of water molecules in tissues, which is a change that improves the study’s diagnostic capacity. These contrast media act by shorting the T1 and T2 relaxation time of the tissues to which they are distributed, which fundamentally leads to an increased signal in T1-weighted sequences. However, if the GBCM concentration is high, T2 shortening is predominant, which causes a decrease in the signal. Nine agents have currently been approved and are available in Europe; their characteristics are summarised in Table 1. Structure and pharmacokinetics Gadolinium (Gd) is a heavy metal with a high paramagnetic capacity and which is not soluble in water. In its free form (Gd3) it is very toxic, and as such, it is necessary to chelate it with different organic ligands, creating gadolinium chelates4. There is a certain tendency for the ion to separate from the ligand in a process called chelation blocking 5. If this process continues, there is transmetalation and this causes NSF6. Transmetalation is a chemical reaction whereby a secondary free metal with affinity for the chelate allows gadolinium release (Gd3). In renal failure patients, it decreases the renal elimination of GBCM; its half-life is extended, which increases the possibility of Gd3 dissociating from the chelate. This facilitates the recruitment of circulating fibrocytes, triggering the fibrosing reaction7,8. The structure of gadolinium chelates may be linear or macrocyclic, with the latter being that which shows higher thermodynamic stability constants. Being hydrophilic compounds, they can be classified9 as ionic and non-ionic, with the latter having lower osmolarity for the same concentration (Table 1). Of all the agents, nonionic linear agents are the least stable and they increase the risk of transmetalation. As such, they are associated with a higher risk of NSF10,11. In terms of the distribution after their intravenous administration (Table 1), GBCM are classified into three types: non-specific extracellular, mixed (hepatospecific extracellular and intracellular distribution with a variable percentage of biliary elimination) and intravascular (they remain in the intravascular space for longer). The vast majority of GBCM used in daily practice are from the first group12. GD chelates have a molecular weight that ranges between 500 and 1,000Da, they are not bound to plasma proteins and Nefrologia 2014;34(4):428-38 short review are not lipophilic, which means that after their intravenous administration, there is a distribution and balance within the extracellular space. All of these characteristics help to create the good glomerular filtration capacity of GD chelates6. They are small molecules that leave the vascular space quickly, with a half-life in plasma of around 15-30 minutes. They do not cross the blood-brain barrier or the cell membrane, and as such, after leaving the vascular space, they are distributed around the interstitial space. They are eliminated, without being metabolised, through glomerular filtration. In patients with normal renal function, 98% of Gd is eliminated in urine in the first 24 hours13, and it is not eliminated from or reabsorbed into the renal tubule14. Pharmacokinetic studies have demonstrated its elimination by glomerular filtration, extending the contrast’s halflife by more than 30 hours but without side effects of nephrotoxicity. In renal failure patients, peritoneal clearance of GBCM was 3.8ml/minute/1.73m2 with a T1/2 of 52.7 hours, which is not surprising, given the slow clearance of peritoneal dialysis techniques. 75% of doses administered were eliminated by peritoneal dialysis after 5 days and as such, peritoneal dialysis is not an effective technique for eliminating contrast. After two haemodialysis sessions, 95% of the gadolinium dose administered was eliminated but there were no tests of its efficacy in the removing the risk of NSF. However, we recommend that patients on dialysis undergo haemodialysis less than two hours after administration and another haemodialysis session the next day. It is not routinely recommended in non-dialysis patients6. Dose and administration range As a gadolinium atom modifies the relaxation times of many neighbouring hydrogen nuclei, the contrast dose used is low, Table 1. Classification of the different gadolinium-based contrasts according to their distribution Extracellular (non-specific) • Gadopentetate dimeglumine (Gd-DTPA) • Gadoteridol (Gd-HP-DO3A) • Gadodiamide (Gd-DTPA-BMA) • Gadoterate meglumine (Gd-DOTA) • Gadobutrol (Gd-BT-DO3A) • Gadoversetamide Mixed (extracellular/hepatobiliary) • Gadoxetate disodium (Gd-EOB-DTPA) • Gadobenate dimeglumine (Gd-BOPTA) Intravascular • Gadofosveset trisodium 429 Ana Canga et al. Nephrogenic systemic fibrosis short review significantly lower than the quantity of iodine administered for computerised tomography studies15. The most used commercial preparations have a concentration of 0.5 molar (0.5M), and as such, the standard administration dose is 0.1mmol/kg of weight, equivalent to 0.2ml/kg of contrast4. High doses and increases in the accumulated dose increase the risk of NSF6. NEPHROGENIC SYSTEMIC FIBROSIS NSF is an acquired fibrosing disorder that has been observed in patients with severely impaired renal function. Although the term “nephrogenic systemic fibrosis” was adopted in 2005, it was recognised for the first time in 1997 and reported in the year 2000 by Cowper as a scleromyxedema-like illness in dialysis patients1. In our country, Rodríquez Jornet et al. published the first case in 2009, with a detailed pathological review of the patient, and the macroscopic and microscopic images are available at: http://www.revistanefrologia.com/modules. php?name=articulos&idarticulo=129&idlangart=ES16. Table 2 displays the chronology and evolution of the term. Epidemiology NSF affects most cases of patients with impaired renal function, particularly those with an estimated glomerular filtration rate of less than 30ml/min/1.73m2 independently of the origin of renal damage (acute, chronic or haemodialysis patients)2,3, who are administered GBCM. According to Zou et al., the two most affected groups are patients with chronic renal failure (CRF) on dialysis (85% of cases) and those with acute renal failure17. Another patient group that may be affected are those with liver failure who have acute hepatorenal syndrome18,19. It is well-known that not all risk patients exposed to GBCM have a disease6. NSF is more common in middle-aged patients (50-60 years of age)20, although it may affect children and the elderly21,22. There are no differences according to race or sex, or any relationship with the cause or duration of CRF20. Although various authors have reported different prevalences in accordance with the population selected, it is currently estimated that there is a mean incidence of 0%-18% in the risk population23. There is a clear relationship between the dose of GBCM used and the risk of NSF, with there being a NSF incidence close to 0 after an exposure to a standard dose15,24. Differences were also reported in the incidence of NSF according to the characteristics of the molecule, with a greater number of cases of NSF having been recorded after exposure to non-ionic linear compounds. As we have mentioned before, it seems that there is a greater risk of incidence in the peritoneal dialysis patient group25. 430 Thanks to the knowledge of risk factors and the better use of GBCM, the number of cases of NSF has decreased significantly26. Since 2008, there have been no cases of any CM being reported without these CM being replaced27. Many hospitals have continued to use the same GBCM but have changed the patterns of use. Aetiopathogenesis Although the exact pathogenesis of NSF continues to be unknown, the only solid association identified in all patients with NSF is renal failure, both in its chronic and acute forms, and its presence is a sine qua non condition for the diagnosis of the disease28. However, only a small percentage of the risk population exposed to GBCM develops NSF, and cases of NSF have also been reported without exposure to GBCM29. Table 2. Chronology and evolution of the term “nephrogenic systemic fibrosis” 2000 First report of NSF in the literature as a skin condition “scleromyxedema-like” in dialysis patients1 2001 Nephrogenic fibrosing dermopathy is reported as a new disease2 2003 The systemic involvement of the disease becomes known for the first time24 2005 The term “nephrogenic systemic fibrosis” is recorded for the first time72 2006 Two publications warn about the potential relationship between gadolinium and NSF42,43 The FDA publishes its first public warning with regard to this association72 2007 The FDA74 and the European Medicines Agency (EMA)75 make it compulsory to introduce a warning on the data sheets of GBCM The European Society of Urogenital Radiology (ESUR)76 and the American College of Radiology (ACR)77 publish guidelines on the use of GBCM in patients with renal failure 2011 An expert group publishes the first recommendations for defining and diagnosing NSF28 FDA: Food and Drug Administration, NSF: nephrogenic systemic fibrosis, GBCM: gadolinium-based contrast media. Nefrologia 2014;34(4):428-38 Ana Canga et al. Nephrogenic systemic fibrosis Given that exposure to GBCM does not explain all cases of NSF, other coadjuvant risk factors have been studied that may contribute to its development, many of them associated with situations of renal failure. Pro-inflammatory factors: vessel injury, surgery, thrombosis, procoagulant stages, severe infection, chronic hepatitis C, chronic liver disease and liver transplantation, hyperparathyroidism and hypothyroidism. Biochemical factors: acidosis, intravenous iron, erythropoietin, calcium and phosphorus30. Pathophysiological mechanisms The two forms, free Gd ions and the chelate-Gd complex may cause the release of cytokines, stimulating skin macrophages (Gd-free ions) or peripheral blood monocytes (chelate-Gd complexes). All of these processes (macrophage activation, pro-inflammatory cytokine release, differentiation of fibrocytes in blood, activation of fibroblasts, TGF-β pathways, metallothionein, FGF-23 and Klotho protein) stimulate fibroblasts30, a response that creates collagen deposits and fibrosis by increasing transforming growth factor beta 1 levels31. The presence of renal failure contributes to the release of free GD3 by increasing transmetalation in a uraemic environment and decreasing the glomerular filtration rate32. A complete diagram with pathophysiological mechanisms published by Chopra et al. is available at http:// www.hindawi.com/journals/ijn/2012/912189/fig1/30. Diagnosis It presents clinically as a thickening and hardening of the skin, associated with pain, muscle weakness, bone pain and joint contractures, which causes severe disability3. Over time there may be loss of flexibility, limited mobility and joint contractures2,34. Lesions may appear in the form of plaques (58%) with irregular edges and papules (32%), nodules (17%), macules, vesicles, blisters, bullae and ulcers2,21,35,36. It typically affects the legs, but may be found anywhere apart from the face in most cases35. These skin lesions progress over time to fibrotic skin surrounded by wrinkles, also known as “orange peel”37. Most lesions are hyperpigmented and erythematous (39%), but their colour can vary (purple, brown, yellow, pink, orange-red, grey-brown)35,38. Sometimes these symptoms can be confused and wrongly treated as cellulitis6. Kroshinsky et al. published the case of a 46-year-old woman with CRF, oedema in her legs and skin changes, who was examined and a differential diagnosis was carried out, with macroscopic and microscopic images of the dermis being created39. At the time this condition was first reported, scientists thought that it was just a skin disorder, but it is nowadays well-known that it affects joints, the muscular system, the testicles, the kidney, the heart and the dura mater31,40,41. Another sign of interest is that it has similar symptoms to conjunctivitis in 75% of cases6. Nefrologia 2014;34(4):428-38 short review The onset of symptoms is variable; it generally occurs between two weeks and two months after exposure to GBCM. However, delayed onset has also been reported, years after exposure17. The histological diagnosis is based on a skin biopsy where skin fibrosis is observed, with thickened collagen bundles and a variable quantity of elastic fibres and mucin. The mediating cell is the circulating fibrocyte (CD34 and positive procollagen I in the immunohistochemistry stain)28,42. In most cases, the inflammatory cells are not present and on some occasions, perivascular mononuclear infiltrate has been observed43. Sanyal et al. carried out a histological review of a clinical case with an electron microscope and energy dispersive x-ray fluorescence44. With regard to its association with GBCM, the first publications are from 200645,46, with the presence of gadolinium in tissues being demonstrated only one year later47,48. Under normal conditions, GBCM are eliminated by glomerular filtration in 1-2 days. Prognosis The natural outcome of NSF is not fully known. It has been reported that in up to 5% of cases, it may have a fulminant course20. A third will have a mild course without functional limitation17. There is increased mortality after 24 months of skin manifestations of NSF49. The true mortality rate is unknown and is difficult to determine, given the high prevalence of other comorbidities34. Treatment There is no evidence of effective treatment and only in transplant patients has an improvement or a detention in the progression of renal disease been achieved in the case of acute renal failure50. As mentioned above, GBCM molecular weight allows glomerular filtration6 and given these characteristics, there is the possibility of elimination with haemodialysis51. Several authors have carried out studies that confirm the elimination of various types of GBCM with three haemodialysis sessions of three hours each. Based on these results, the European Society of Radiology recommends carrying out nine hours of haemodialysis over three sessions. However, gadofosveset is an agent that is difficult to eliminate by haemodialysis due to a large proportion of it being bound to serum albumin6. Broome et al. presented a series with three patients who developed NSF despite undergoing the previously indicated haemodialysis sessions52. To present, no studies have been carried out on continuous haemofiltration or continuous venovenous haemodiafiltration. 431 Ana Canga et al. Nephrogenic systemic fibrosis short review Most treatments proposed are still being researched and they are currently yielding suboptimal results (oral steroids, extracorporeal photopheresis, plasmapheresis, thalidomide, cyclophosphamide, pentoxifylline, intravenous immunoglobulin, interferon alpha and vitamin D, ultraviolet radiation and etanercept)20. Recently, combined treatments with imatinib and extracorporeal photopheresis have been attempted53,54. The efficacy of treatment with alefacept was also confirmed in three patients with NSF55. The improvement in renal function (transplantation and resolution of acute renal failure) may slow down and even reverse the process20. However, in reality, no treatment has shown to be effective; therefore, prevention is important. PREVENTION OF NEPHROGENIC SYSTEMIC FIBROSIS Identification of patients with chronic kidney disease The classification of chronic kidney disease (CKD) followed the initial publication of the National Kidney Foundation through the Kidney Disease Outcomes Quality Initiative (K-DOQI) guidelines56. The definition of CKD by K-DOQI is as follows: Renal damage for at least three months, defined by structural or functional abnormalities of the kidney or without a decrease in the GFR and shown by pathological changes or renal damage markers (changes in the composition of blood or urine or changes in images of the kidney). The international organisation KDIGO (Kidney Disease Global Outcomes; http://www.kdigo.org/) recommends using prediction equations to calculate the GFR based on SCr. In adults, the formulae most used are those of the Modification of Diet in Renal Disease (MDRD) study and that of Cockcroft and Gault58. There are certain circumstances in which the first is not validated (Table 3) and in order to estimate the GFR, 24-hour urine should be collected or studies of creatinine clearance in 24hour urine, iothalamate, iohexol or insulin should be carried out. In any case, the estimation of GFR using the MDRD formula is more accurate that SCr, and considering these limitations, the doctor may obtain valid information about renal function. Recently, KDIGO recommended a new formula for calculating renal function, called CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration), which is more accurate than MDRD for values close to 60ml/min59. Likewise, it updated the CKD classification by incorporating the CGA concept: C: cause of CKD, G: GFR incorporating groups 3a and 3b, and A: albuminuria with three subgroups: A1 (<30mg/g of creatinine), A2 (30-300) and A3 (>300)60 (Table 4). There are occasionally no data on renal function. In patients who have unknown renal function and who require an x-ray examination with gadolinium, a series of parameters should be considered, such as renal failure risk factors, which will mean that the examination must be delayed until their exact renal function is known (Table 5). The study of risk factors must be part of the routine before using GBCM in any hospital. GFR <60ml/min/1.73m2 for more than three months, with or without renal damage. IMMEDIATE ADVERSE REACTIONS TO GADOLINIUMBASED CONTRAST MEDIA It is common in consultations for renal function to be studied simply by measuring serum creatinine (SCr). However, and although it is true that SCr is a good follow-up parameter of the evolution of filtration, it is not always equivalent to glomerular filtration. SCr also depends on factors other than the GFR, such as tubular elimination and the generation and extrarenal elimination of creatinine, which explains the wide range for SCr in healthy individuals. Some studies57 show a high percentage of males and particularly of females who have reductions in the GFR with normal SCr. Even with creatinine ranges between 1.3 and 2.5mg/dl, there are significant percentages of very severe renal failure (GFR below 30ml/min/1.73m2). Therefore, the real prevalence of individuals with renal failure appears to be higher than that which can be determined by studying SCr. The results of these observations are important. This “hidden” renal failure may easily worsen due to the large amount of medications, particularly in glomerular haemodynamics, such as nonsteroidal anti-inflammatory drugs, angiotensin-convertingenzyme inhibitors and other types of drugs. Likewise, patients often undergo x-ray examinations when there is an inadequate evaluation of renal function, based only on plasma creatinine. GBCM are very safe drugs, with a low immediate adverse reaction (IAR) rate of 0.07%-2.4%61-63, mostly of a 432 Table 3. Circumstances in which the MDRD (Modification of Diet in Renal Disease) equation is not valid for calculating the glomerular filtration rate - Age <18 or >70 years old - Severe malnutrition and obesity - Musculoskeletal disease - Paraplegia or tetraplegia - Vegetarian diet - Rapid changes in renal function - Pregnancy - Drugs that increase the values of creatinine: trimethoprim, cimetidine, some fibrates and certain cephalosporins Nefrologia 2014;34(4):428-38 Ana Canga et al. Nephrogenic systemic fibrosis short review Table 4. Classification of chronic kidney disease57 Grade Description GFR (mL/min/1.73 m2) 1 Renal damage with a normal or high GFR 2 Renal damage with a slightly decreased GFR 60-89 3 Moderate decrease in GFR 3a 3b 59-30 29-16 4 Severe decrease in the GFR 15-29 5 Renal failure >90 <15 (or dialysis) GFR: glomerular filtration rate mild nature, mainly nausea or headaches at the time of injection. Although all GBCM show quite a similar IAR incidence64, there are differences in their occurrence that cannot seem to be explained by their physicochemical characteristics65,66 (Table 6). Among IAR to GBCM, we must highlight allergic reactions, due to their relevance, which are defined as a type of adverse reaction measured immunologically by antibodies or lymphocytes, characterised by being specific and recurrent if the patient is exposed to the drug again67. Two types of allergic reaction to x-ray contrast media are distinguished depending on the moment of presentation: immediate and non-immediate or delayed68. Immediate allergic reactions are measured by immunoglobin E; if a systemic allergic reaction develops, there is anaphylaxis. This is caused by the release of histamines and other mediators, causing symptoms that may put the life of the patients at risk: laryngeal oedema, angioedema, upper airway obstruction, urticarial, nausea, vomiting, low blood pressure and/or shock. The occurrence of allergic reactions to GBCM is unpredictable, although it is known that its incidence increases in asthmatic patients and in those with food allergies and/or medication allergies58,69. With regards to how to act against an allergic reaction to a GBCM, Figure 1 displays an algorithm, which schematically shows how to manage these emergency situations in the x-ray diagnosis department. LEARN FROM EVIDENCE was created, which led to an overenthusiastic use of GBCM, which were often used as replacements for iodinated contrasts in computerised tomography or conventional angiography studies in patients who were allergic to iodinated contrasts or in those with renal failure and even in MRI, at doses much higher than those recommended. This use of GBCM, before NSF was reported, was carried out without any type of control in terms of dose or administration times and without taking any precautions in relation to the renal function of patients. The reporting of this delayed and potentially serious adverse reaction marked a turning point that forced x-ray departments to establish new guidelines aimed at protecting patients. Although the initial information may have been confusing, some evidence was clear and shed light with regard to the measures to adopt to prevent disease: it was only reported in patients with severe renal failure (GFR<30), its incidence was related to the administration of high doses of gadolinium and it was more common in patients with pro-inflammatory symptoms. Table 5. Chronic kidney disease risk factors – Age >65 years old – High blood pressure – Diabetic – History of cardiovascular disease – Obesity Clinical use and abuse Since the introduction of GBCM in MRI, its applications have been increasing daily, and it is now used in all organs of the body. During the first few years, a false sense of security Nefrologia 2014;34(4):428-38 – History of renal failure or some type of kidney disease (single kidney, renal transplantation or renal neoplasm) – Direct family member with kidney disease 433 Ana Canga et al. Nephrogenic systemic fibrosis short review Table 6. Percentage of immediate adverse reactions to gadolinium-based contrast media Prince et al.65 Several authors 0.33 % n=3371 Gadoteridol (Prohance®) Gadopentetate dimeglumine (Magnevist®) 0.05 % n=66,157 Gadodiamide (Omniscan®) 0.02 % n=55,703 0.39 % n=254 2.4 % n=15 496 78 79 n=24,308 0.55 % Gadobutrol (Gadovist®) Gadobenate dimeglumine (Multihance®) 0.12 % n=33,114 0.20 % n=7490 0.06% n=3097 0.40 % Gadoterate meglumine (Dotarem®) Bruder et al.66 0.25 % n=1208 n=14,29980 0.23 % n=2201 0.76 % n=23,53381 0.47 % n=428 If after administration of gadolinium-based contrast... DOUBTFUL SYMPTOMS URTICARIA-ANGIOEDEMA ANAPHYLAXIS Use a pulse oximeter Measure blood pressure/heart rate Use a pulse oximeter Measure blood pressure/ heart rate Use a pulse oximeter Measure blood pressure/ heart rate I.v. administration 1 hour in the unit 1 amp. (5mg) i.v. Polaramine®; <12 years: 0.15-0.3mg/kg 1mg/kg i.v. Urbason® 0.3-0.5cc i.m. administration 1/1,000 EPINEPHRINE to the thigh (children 0.1cc/10kg) If after 1h symptoms persist, extract tryptase in blood Refer to the emergency department CALL THE ICU Venous administration with saline solution Trendelenburg position Oxygen therapy (6-8lpm at 100%) ADJUVANT THERAPY 40-80mg i.v. Urbason® (1-2mg/kg) 1 amp. (5mg) i.v. Polaramine®; <12 years: 0.15-0.3mg/kg Nebulised salbutamol if bronchospasm occurs Consult the allergology service Refer according to the ICU Figure 1. Protocol for treating adverse reactions to gadolinium. i.m.: intramuscular, i.v.: intravenous, ICU: intensive care unit. 434 Nefrologia 2014;34(4):428-38 Ana Canga et al. Nephrogenic systemic fibrosis Clinical limitations in the use of gadolinium-based contrast media The main limitation with regard to the use of GBCM in MRI is the difficulty of knowing the GFR of patients, particularly outpatients. In this regard, collaboration between the x-ray department, which would have to routinely record renal failure risk factors (Table 4) before carrying out the GBCM study, and the doctor who requests the test, who must provide information about the patient’s renal function and assess the risk/benefit of the test requested for the patient. If any of the risk factors of renal failure are confirmed or the GFR of the patient cannot be excluded or assessed, it would be preferable to postpone it until MDRD or CKD-EPI are determined in another test. Since gadolinium has been considered an agent the potentially causes NSF, restrictive guidelines have been designed for its administration (Table 7), with the most important aspects being the possession of recent GFR data and the adjustment of doses used in accordance with the latter (Table 8). In 2010, the U.S. Food and Drug Administration (FDA) established general precautions on the use of GBCM and limited Magnevist®, Omniscan® and Optimark® GBCM in patients with acute renal failure and high-risk severe CRF43. Two years after the recommendations carried out by the FDA, a 71% decrease was observed in MRI in patients with MDRD 30ml/min/1.73m2 and a 99% increase was observed in requests for SCr a month before carrying out MRI70. A year before, the European Medicines Agency also contraindicated the use of the aforementioned GBCM in patients with severe renal failure, infants and those awaiting liver transplantation43. short review According to Bennet et al., in Denmark since 2007 and in the United States since 2009, no new cases of NSF have been published71. The possibility of this adverse reaction occurring should not limit clinical action. It is essential to find a balance between the guarantee of patient safety and the carrying out of the tests necessary for correct clinical management. As such, the need for a test and its effectiveness will be discussed clinically, and other diagnostic options will be taken into account, as well as alternative contrasts. In short, the risk/benefit will be weighed up. CONCLUSIONS GBCM are a group of drugs with differentiated physiochemical characteristics that are increasingly being used in diagnosis by MRI. Due to the fact that they were initially used without taking patients’ renal function into account, and without an exact knowledge of the toxic doses permitted, a series of adverse effects appeared, and in particular, the predominantly dermatological multiple organ fibrosing disorder subsequently known as NSF, which discredited its use. The reporting of this delayed and potentially severe adverse reaction marked a turning point, since it made it compulsory to establish consensuses to protect patients by assessing the GFR and risk factors. All of this along with dose adjustment have decreased the number of adverse reactions significantly and in the last five years there have hardly been any published cases with the use of gadolinium. Table 7. Measures to avoid nephrogenic systemic fibrosis development Table 8. Administration of gadolinium adjusted to renal function - Know the possibility of this delayed adverse reaction to identify it and warn about it GFR >60mL/min - Avoid the administration of gadolinium in patients with a glomerular filtration rate <30mL/min (1% of the population) 82 - Use the minimum dose diagnosed, respecting a 1 week interval to repeat an MRI with contrast. The risk increases in patients with end-stage renal disease from 1.5% with a single dose to 12.1% with a double dose (frequently used in angiographic and oncological studies) - I n f o r m t h e p a t i e n t a b o u t t h e r i s k o f s u ff e r i n g this adverse reaction and consider the possibility o f i n t ro d u c i n g t h i s i n f o r m a t i o n i n t h e i n f o r m e d consent Nefrologia 2014;34(4):428-38 There are no limitations on the administration of Gd, but it is necessary to always try and respect the measures with regard to dose and administration time GFR 30-60mL/min It may be administered whenever the maximum measures of safety are taken into account in the doses administered and at intervals of 1 week between MRI GFR <30mL/min Do not administer Gd. Seek diagnostic alternatives GFR: glomerular filtration rate, Gd: gadolinium. 435 short review As for IAR, all GBCM have a low and similar incidence, although there are some differences between them, with gadodiamide having the lowest incidence 63,64,67. These reactions, although they are generally mild, can occasionally be severe and even fatal. Patient protection is key when GBCM are used in x-rays. The identification and selection of patients at risk, the assessment of the risk and benefit and informing the patient about the adverse effects are essential. In most cases, it is necessary to assess the patient, make a multidisciplinary decision, and in particular, treat every case individually. Conflicts of interest The content of this review is based on an update of Working Session presentations sponsored by GE Healthcare entitled What happened to NSF? The current situation, which took place at the XXXI SERAM Conference (Granada, 2012). The publication of this review was carried out independently of the Working Session sponsor. REFERENCES 1. Cowper SE, Robin HS, Steinberg SM, Su LD, Gupta S, LeBoit PE. Scleromyxoedema-like cutaneous diseases in renal-dialysis patients. Lancet 2000;356:1000-1. 2. Cowper SE, Su LD, Bhawan J, Robin HS, LeBoit PE. Nephrogenic fibrosing dermopathy. Am J Dermatopathol 2001;23(5):383-93. 3. Swartz RD, Crofford LJ, Phan SH, Ike RW, Su LD. Nephrogenic fibrosing dermopathy: a novel cutaneous fibrosing disorder in patients with renal failure. Am J Med 2003;114(7):563-72. 4. Weinmann HJ, Brasch RC, Press WR, Wesbey GE. Characteristic of gadolinium-DTPA complex: a potential MR contrast agent. AJR Am J Roentgenol 1984;142:619-24. 5. Thakral C, Alhariri J, Abraham JL. Long-term retention of gadolinium in tissues from nephrogenic systemic fibrosis patient after multiple gadolinium-enhanced MRI scans: case report and implications. Contrast Media Mol Imaging 2007;2:199-205. 6. Ortega L, Contreras G, Lenz O. ¿Dermopatía fibrotisante nefrogénica o fibrosis sistémica nefrogénica? ¿Qué es lo que sabemos y qué debemos aprender? Nefrologia 2009;29(2):109-17. 7. Perazella MA. Nephrogenic systemic fibrosis, kidney disease, and gadolinium: Is there a link? Clin J Am Soc Nephrol 2007;2(2):2002. 8. Puttagunta NR, Gibby WA, Puttagunta VL. Comparative transmetallation kinetics and thermodynamic stability of gadolinium-DTPA bisglucosamide and other magnetic resonance imaging contrat media. Invest Radiol 1996;31:619-24. 9. Bellin MF, Vasile M, Morel-Precetti S. Currently used non-specific extracellular MR contrast media. Eur Radiol 2003;13:2688-98. 10. Green RWK, Krestin GP. Non-tissue specific extra cellular MR contrast 436 Ana Canga et al. Nephrogenic systemic fibrosis media. In: Thomsen HS (ed). Contrast Media. Safety Issues and ESUR Guidelines. Heidelberg: Springer Verlag; 2006. pp. 107-12. 11. Broome DR. Nephrogenic systemic fibrosis associated with gadolinium based contrast agents: a summary of the medical literature reporting. European Journal of Radiology 2008;66(2):230-4. 12. Méndez Fernández R, Graña López L. Fármacos en radiología. In: Del Cura JL, Pedraza S, Gayete A. Radiología esencial. SERAM, 1.ª ed. Madrid: Editorial Médica Panamericana; 2009. pp. 65-77. 13. Ledneva E, Karie S, Launay-Vacher V, Janus N, Deray G. Renal safety of gadolinium-based contrast media in patients with chronic renal insufficiency. Radiology 2009;250(3):618-28. 14. Bellin MF. MR contrast agents, the old and the new. Eur J Radiol 2006;60:314-23. 15. Prince MR, Zhang H, Morris M, MacGregor JL, Grossman ME, Silberzweig J, et al. Incidence of nephrogenic systemic fibrosis at two large medical centers. Radiology 2008;248(3):807-16. 16. Rodríguez Jornet A, Andreu Navarro FJ, Orellana Fernández R, Ibeas López J, Fortuño Andrés JR. Fibrosis sistémica por gadolinio en insuficiencia renal avanzada. Nefrologia 2009;29(4):358-63. 17. Zou Z, Ma L. Nephrogenic systemic fibrosis: review of 408 biopsyconfirmed cases. Indian J Dermatol 2011;56(1):65-73. 18. Swartz RD, Crofford LJ, Phan SH, Ike RW, Su LD. Nephrogenic fibrosing dermopathy: a novel cutaneous fibrosing disorder in patients with renal failure. Am J Med 2003;114:563-72. 19. Maloo M, Abt P, Kashyap R, Younan D, Zand M, Orloff M, et al. Nephrogenic systemic fibrosis among liver transplant recipients: a single institution experience and topic update. Am J Transplant 2006;6:2212-7. 20. Cowper SE. Nephrogenic Systemic Fibrosis [ICNSFR Website] 20012009. Available at: http://www.icnsfr.org (accessed: October 30, 2012). 21. Jain SM, Wesson S, Hassanein A, Canova E, Hoy M, Fennell RS, et al. Nephrogenic fibrosing dermopathy in pediatric patients. Pediatr Nephrol 2004;19(4):467-70. 22. Jan F, Segal JM, Dyer J, Leboit P, Siegfried E, Frieden IJ. Nephrogenic fibrosing dermopathy: two pediatric cases. J Pediatr 2003;143(5):67881. 23. Prince MR, Zhang HL, Roditi GH, Leiner T, Kucharczyk W. Risk factors for NSF: a literature review. J Magn Reson Imaging 2009;30(6):1298308. 24.Ting WW, Stone MS, Madison KC, Kurtz K. Nephrogenic fibrosing dermopathy with systemic involvement. Arch Dermatol 2003;139:903-6. 25.Centre of Disease Control and Prevention (CDC). Nephrogenic fibrosing dermopathy associated with exposure to gadoliniumcontaining contrast agents-St. Louis, Missouri, 2002-2006. MMWR Morb Mortal Wkly Rep 2007;56:137-41. 26.Thomsen HS, Marckmann P, Logager VB. Enhanced computed tomography or magnetic resonance imaging: a choice between contrast medium-induced nephropathy and nephrogenic systemic fibrosis? Acta Radiol 2007;48:593-6. 27. Reilly RF. Risk for nephrogenic systemic fibrosis with gadoteridol (ProHance) in patients who are on long-term hemodialysis. Clin J Am Soc Nephrol 2008 May;3(3):747-51. 28.Girardi M, Kay J, Elston DM, Leboit PE, Abu-Alfa A, Cowper SE. Nephrogenic systemic fibrosis: clinicopathological definition and workup recommendations. J Am Acad Dermatol 2011;65(6):1095-106. Nefrologia 2014;34(4):428-38 Ana Canga et al. Nephrogenic systemic fibrosis 29.Kaewlai R, Abujudeh H. Nephrogenic systemic fibrosis. AJR Am J Roentgenol 2012;199(1):W17-23. 30. Chopra T, Kandukurti K, Shah S, Ahmed R, Panesar M. Understanding nephrogenic systemic fibrosis. Int J Nephrol 2012;2012:912189. 31.Jiménez SA, Artlett CM, Sandorfi N, Derk C, Latinis K, Sawaya H, et al. Dialysis-associated systemic fibrosis (nephrogenic fibrosing dermopathy): study of inflammatory cells and transforming growth factor β1 expression in affected skin. Arthritis Rheum 2004;50(8):2660-6. 32. Collidge TA, Thomson PC, Mark PB, Traynor JP, Jardine AG, Morris ST, et al. Gadolinium-enhanced MR imaging and nephrogenic systemic fibrosis: retrospective study of a renal replacement therapy cohort. Radiology 2007;245:168-75. 33. Scheinfeld N. Nephrogenic fibrosing dermopathy: a comprehensive review for the dermatologist. Am J Clin Dermatol 2006;7(4):237-47. 34.Cowper SE. Nephrogenic fibrosing dermopathy: the first 6 years. Curr Opin Rheumatol 2003;15(6):785-90. 35.Cowper SE, Rabach M, Girardi M. Clinical and histological findings in nephrogenic systemic fibrosis. Eur J Radiol 2008;66(2):191-9. 36.Panda S, Bandyopadhyay D, Tarafder A. Nephrogenic fibrosing dermopathy: a series in a non-Western population. J Am Acad Dermatol 2006;54(1):155-9. 37. Bangsgaard N, Marckmann P, Rossen K, Skov L. Nephrogenic systemic fibrosis: late skin manifestations. Arch Dermatol 2009;145(2):183-7. 38.Evenepoel P, Zeegers M, Segaert S, Claes K, Kuypers D, Maes B, et al. Nephrogenic fibrosing dermopathy: a novel, disabling disorder in patients with renal failure. Nephrol Dial Transplant 2004;19(2):469-73. 39. Kroshinsky D, Kay J, Nazarian RM. Case records of the Massachusetts General Hospital. Case 37-2009. A 46-year-old woman with chronic renal failure, leg swelling, and skin changes. N Engl J Med 2009;361:2166-76. 40. Gibson SE, Farver CF, Prayson RA. Multiorgan involvement in nephrogenic fibrosing dermopathy: an autopsy case and review of the literature. Arch Pathol Lab Med 2006;130(2):209-12. 41.Levine JM, Taylor RA, Elman LB, Bird SJ, Lavi E, Stolzenberg ED, et al. Involvement of skeletal muscle in dialysis-associated systemic fibrosis (nephrogenic fibrosing dermopathy). Muscle Nerve 2004;30(5):569-77. 42.Abu-Alfa AK. Nephrogenic systemic fibrosis and gadolinium-based contrast agents. Adv Chronic Kidney Dis 2011;18(3):188-98. 43.Galan A, Cowper SE, Bucala R. Nephrogenic systemic fibrosis (nephrogenic fibrosing dermopathy). Curr Opin Rheumatol 2006;18(6):614-7. 44.Sanyal S, Marckmann P, Scherer S, Abraham JL. Multiorgan gadolinium (Gd) deposition and fibrosis in a patient with nephrogenic systemic fibrosis—an autopsy-based review. Nephrol Dial Transplant 2011;26:3616-26. 45.Grobner T. Gadolinium: a specific trigger for the development of nephrogenic fibrosing dermopathy and nephrogenic systemic fibrosis? Nephrol Dial Transplant 2006;21(4):1104-8. 46.Marckmann P, Skov L, Rossen K, Dupont A, Damholt MB, Heaf JG. Nephrogenic systemic fibrosis: suspected causative role of gadodiamide used for contrast-enhanced magnetic resonance imaging. J Am Soc Nephrol 2006;17:2359-62. 47.High WA, Ayers RA, Chandler J, Zito G, Cowper SE. Gadolinium is detectable within the tissue of patients with nephrogenic systemic fibrosis. J Am Acad Dermatol 2007;56(1):21-6. Nefrologia 2014;34(4):428-38 short review 48. Boyd AS, Zic JA, Abraham JL. Gadolinium deposition in nephrogenic fibrosing dermopathy. J Am Acad Dermatol 2007;56(1):27-30. 49.Todd DJ. Nephrogenic systemic fibrosis: what nephrologist need to know. Nephrol Rounds 2007;5:1-6. 50.Mendoza FA, Artlett CM, Sandorfi N, Latinis K, Piera-Velazquez S, Jimenez SA. Description of 12 cases of nephrogenic fibrosing dermopathy and review of the literature. Semin Arthritis Rheum 2006;35:238-49. 51. Okada S, Katagirir K, Kumazaki T, Yokoyama H. Safety of gadolinium contrast agent in hemodialisis patients. Acta Radiol 2001;42:33941. 52.Broome DR, Girguis MS, Baron PW, Cottrell AC, Kjellin I, Kirk GA. Gadodiamide-associated nephrogenic systemic fibrosis: Why radiologists should be concerned. AJR Am J Roentgenol 2007;188:586-92. 53. Gilliet M, Cozzio A, Burg G, Nestle FO. Successful treatment of three cases of nephrogenic fibrosing dermopathy with extracorporeal photopheresis. Br J Dermatol 2005;152(3):531-6. 54.Kay J, High WA. Imatinib mesylate treatment of nephrogenic systemic fibrosis. Arthritis Rheum 2008;58(8):2543-8. 55.Robinson R, Routhouska SB, Paspulati RM, Korman NJ. Alefacept therapy for nephrogenic systemic fibrosis: a case series. J Drugs Dermatol 2011;10:922-4. 56.National Kidney Foundation. K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification and stratification. Am J Kidney Dis 2002;39(2 Suppl 1):S1-266. 57. Fernández Fresnedo G, De Francisco ALM, Rodrigo E, Piñera C, Herráez I, Ruiz C, et al. Insuficiencia renal «oculta» por valoración de la función renal mediante creatinina sérica. Nefrologia 2002;22:144-51. 58.Gracia S, Montañés R, Bover J, Cases A, Deulofeu R, Martín de Francisco AL, et al. Documento de consenso: Recomendaciones sobre la utilización de ecuaciones para la estimación del filtrado glomerular en adultos. Nefrologia 2006;26:658-65. 59.Levey AS, Stevens LA, Schmid CH, Zhang YL, Castro AF 3rd, Feldman HI, et al.; CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration). A new equation to estimate glomerular filtration rate. Ann Intern Med 2009;150(9):604-12. 60.KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Available at: http://www. kdigo.org/clinical_practice_guidelines/pdf/CKD/KDIGO_2012_CKD_ GL.pdf 61.American College of Radiology. Manual on Contrast Media, version 7, 2010. Available at: http://xray.ufl.edu/files/2008/06/ FullManualACRContrastVersion7.pdf (accessed: June 28, 2013). 62.Hunt CH, Hartman RP, Hesley GK. Frequency and severity of adverse effects of iodinated and gadolinium contrast materials: retrospective review of 456,930 doses. AJR Am J Roentgenol 2009;193(4):1124-7. 63.Li A, Wong CS, Wong MK, Lee CM, Au Yeung MC. Acute adverse reactions to magnetic resonance contrast media gadolinium chelates. Br J Radiol 2006;79(941):368-71. 64.Runge VM. Safety of approved MR contrast media for intravenous injection. J Magn Reson Imaging 2000;12(2):205-13. 65.Prince MR, Zhang H, Zou Z, Staron RB, Brill PW. Incidence of immediate gadolinium contrast media reactions. AJR Am J Roentgenol 2011;196(2):W138-43. 437 short review 66.Bruder O, Schneider S, Nothnagel D, Pilz G, Lombardi M, Sinha A, et al. Acute adverse reactions to gadolinium based contrast agents in CMR. JACC Cardiovasc Imaging 2011;4(11):1171-6. 67.Cortada Macías JM, López Serrano MC, Blasco A, Mayorga C, Torres MJ. Introducción, conceptos generales, epidemiología. Fisiopatología: los fármacos como antígenos. In: Peláez A, Dávila I, eds. Tratado de alergología. Madrid: Ergon; 2007. pp. 1297-324. 68.Gracia Bara MT, Herrero Lopez T, Irirarte Sotés P, Cruz Grandos S, Infante Herrero S. Reacciones alérgicas inducidas por fármacos poco habituales: de masa molecular baja o inorgánicos. En: Peláez A, Dávila I, eds. Tratado de alergología. Madrid: Ergon, 2007; 1.531-1.556. 69. Jung JW, Kang HR, Kim MH, Lee W, Min KU, Han MH, et al. Immediate hypersensitivity reaction to gadolinium-based MR contrast media. Radiology 2012;264(2):414-22. 70.Kim KH, Fonda JR, Lawler EV, Gagnon D, Kaufman JS. Change in use of gadolinium-enhanced magnetic resonance studies in kidney disease patients after US Food and Drug Administration warnings: a cross-sectional study of Veterans Affairs Health Care System data from 2005-2008. Am J Kidney Dis 2010;56:458-67. 71.Bennett CL, Qureshi ZP, Sartor AO, Norris LB, Murday A, Xirasagar S, et al. Gadolinium-induced nephrogenic systemic fibrosis: the rise and fall of an iatrogenic disease. Clin Kidney J 2012;5:82-8. 72.Daram SR, Cortese CM, Bastani B. Nephrogenic fibrosing dermopathy/nephrogenic systemic fibrosis: report of a new case with literature review. Am J Kidney Dis 2005;46(4):754-9. 73.United States Food and Drug Administration Web site. Gadolinium-containing contrast agents for magnetic resonance imaging (MRI): Omniscan, OptiMARK, Magnevist, ProHance, and MultiHance. Available at: http://www.fda.gov/Safety/MedWatch/ SafetyInformation/SafetyAlertsforHumanMedicalProducts/ Ana Canga et al. Nephrogenic systemic fibrosis ucm150564.htm (update: December 22, 2006; accessed: September 30, 2011). 74. United States Food and Drug Administration Web site. FDA requests boxed warning for contrast agents used to improve MRI images. Available at: http://www.fda.gov/NewsEvents/ N e w s ro o m / P re s s A n n o u n c e m e n t s / 2 0 0 7 / u c m 1 0 8 9 1 9 . h t m (update: June 18, 2009; accessed: October 30, 2012). 75. European Medicines Agency Web site. Vasovist and nephrogenic systemic fibrosis (NSF). Available at: http://www.ema.europa. eu/docs/en_GB/document_library/Public_statement/2009/11/ WC500015607.pdf (accessed: October 30, 2012). 76.Thomsen HS. ESUR guideline: gadolinium–based contrast media and nephrogenic systemic fibrosis. Eur Radiol 2007;17(10):2692-6. 77.Kanal E, Barkovich AJ, Bell C, Borgstede JP, Bradley WG Jr, Froelich JW, et al. ACR guidance document for safe MR practices: 2007. AJR Am J Roentgenol 2007;188(6):1447-74. 78.Nelson KL, Gifford LM, Lauber-Huber C, Gross CA, Lasser TA. Clinical safety of gadopentetate dimeglumine. Radiology 1995;196(2):439-43. 79.Herborn CU, Honold E, Wolf M, Kemper J, Kinner S, Adam G, et al. Clinical safety and diagnostic value of the gadolinium chelate gadoterate meglumine (Gd-DOTA). Invest Radiol 2007;42(1):5862. 80.Forsting M, Palkowitsch P. Prevalence of acute adverse reactions to gadobutrol: a review of 14,299 patients from observational trials. Eur J Radiol 2010;74(3):e186-92. 81.Bleicher AG, Kanal E. Assessment of adverse reaction rates to a newly approved MRI contrast agent: review of 23,553 administrations of gadobenate dimeglumine. AJR Am J Roentgenol 2008;191(6):W307-11. 82.Aguilera C, Agustí A. Preguntas y respuestas en farmacología clínica. Fibrosis sistémica nefrogénica y contrastes de gadolinio. Med Clin (Barc) 2011;136(14):643-5. Sent to review: 27 Nov. 2013 | Accepted: 8 Apr. 2014 438 Nefrologia 2014;34(4):428-38 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society special articles Treatment of hyponatremia induced by the syndrome of Inappropriate antidiuretic hormone secretion: a multidisciplinary algorithm Isabelle Runkle1, Carles Villabona2, Andrés Navarro3, Antonio Pose4, Francesc Formiga5, Alberto Tejedor6, Esteban Poch7 1 Servicio de Endocrinología. Hospital Universitario Clínico San Carlos. Madrid (Spain); 2 Servicio de Endocrinología. Hospital Universitari de Bellvitge. L’Hospitalet de Llobregat, Barcelona (Spain); 3 Servicio de Farmacia Hospitalaria. Hospital General Universitario de Elche. Elche, Alicante (Spain); 4 Servicio de Medicina Interna. Hospital Universitario de Santiago de Compostela. Santiago de Compostela, La Coruña (Spain); 5 Servicio de Medicina Interna. Hospital Universitari de Bellvitge. L’Hospitalet de Llobregat, Barcelona (Spain); 6 Servicio de Nefrología. Hospital General Universitario Gregorio Marañón. Madrid (Spain); 7 Servicio de Nefrología. Hospital Clínic. Barcelona (Spain) Nefrologia 2014;34(4):439-50 doi:10.3265/Nefrologia.pre2014.Apr.12220 ABSTRACT Introduction: The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most frequent cause of hyponatremia in a hospital setting. However, detailed protocols and algorithms for its management are lacking. Our objective was to develop 2 consensus algorithms for the therapy of hyponatremia due to SIADH in hospitalized patients. Material and methods: A multidisciplinary group made up of 2 endocrinologists, 2 nephrologists, 2 internists, and one hospital pharmacist held meetings over the period of a year. The group worked under the auspices of the European Hyponatremia Network and the corresponding Spanish medical societies. Therapeutic proposals were based on widely-accepted recommendations, expert opinion and consensus guidelines, as well as on the authors’ personal experience. Results: Two algorithms were developed. Algorithm 1 addresses acute correction of hyponatremia posing as a medical emergency, and is applicable to both severe euvolemic and hypovolemic hyponatremia. The mainstay of this algorithm is the iv use of 3% hypertonic saline solution. Specific infusion rates are proposed, as are steps to avoid or reverse overcorrection of serum sodium levels. Algorithm 2 is directed to the therapy of SIADH-induced mild or moderate, non-acute hyponatremia. It addresses when and how to use fluid restriction, solute, furosemide, and tolvaptan to achieve eunatremia in patients with SIADH. Conclusions: Two complementary strategies were elaborated to treat SIADH-induced hyponatremia in an attempt to increase awareness of its importance, simplify its therapy, and improve prognosis. Keywords: Hyponatremia. SIADH. Antidiuretic hormone. Tratamiento de la hiponatremia secundaria al síndrome de secreción inadecuada de la hormona antidiurética: algoritmo multidisciplinar RESUMEN Introducción: El síndrome de secreción inadecuada de la hormona antidiurética (SIADH) es la causa más frecuente de hiponatremia en el paciente hospitalizado. Sin embargo, faltan protocolos y algoritmos concretos que faciliten su abordaje terapéutico. Nuestro objetivo fue el desarrollo de dos algoritmos de tratamiento de la hiponatremia secundaria al SIADH en el paciente ingresado. Material y método: Un grupo multidisciplinar español compuesto por 2 especialistas en Endocrinología, 1 en Farmacia Hospitalaria, 2 en Medicina Interna y 2 en Nefrología se reunieron durante un año, bajo la tutela del grupo español del European Hyponatremia Network, y de las respectivas sociedades científicas españolas. Las pautas terapéuticas propuestas fueron basadas en recomendaciones ampliamente aceptadas, la práctica de expertos, guías de consenso, así como en la experiencia clínica de los autores. Resultados: Se elaboraron dos algoritmos de tratamiento. El Algoritmo 1 se dirige al tratamiento de la hiponatremia aguda como urgencia médica de abordaje inmediato, y es de aplicación al tratamiento de la hiponatremia grave tanto de tipo euvolémico como hipovolémico. Se basa en el uso de sueros salinos hipertónicos al 3 % i.v., con pautas de infusión y monitorización. Se expone cómo evitar la hipercorrección de la natremia y cómo corregirla en su caso. El Algoritmo 2 aborda el tratamiento de la hiponatremia no aguda leve o moderada asociada al SIADH. Expone cómo y cuándo usar la restricción hídrica, solutos, furosemida y tolvaptán, para alcanzar eunatremia en el paciente con SIADH. Conclusiones: Se han elaborado dos estrategias complementarias para el tratamiento de la hiponatremia inducida por SIADH, en un intento de fomentar la toma de conciencia acerca de esa patología, simplificar su abordaje y su tratamiento y, así, mejorar su pronóstico. Palabras clave: Hiponatremia. SIADH. Hormona antidiurética. Correspondence: Esteban Poch Servicio de Nefrología. Hospital Clínic. Villarroel, 170. 08036 Barcelona. (Spain) [email protected] * In agreement with the authors and the editors, this paper has been published also in Medicina Clinica: Med Clin (Barc) 2013;141(11):507.e1-507.e10. http://dx.doi.org/10.1016/j.medcli.2013.09.002 439 special articles INTRODUCTION The Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) is characterized by the presence of hypotonic hyponatremia in a context of inadequately diluted urine given the hypoosmolality in plasma, in the absence of a low effective circulating volume. (either with hypovolemia or hypervolemia). For its diagnosis, the following conditions must be excluded: hypotension, renal failure, adrenal insufficiency, severe hypothyroidism, as well as non-osmotic physiologic stimuli of arginine vasopressin (AVP) secretion. In SIADH, a lowering of plasma osmolality (Posm) does not inhibit AVP secretion as expected, and free water is inappropriately reabsorbed at the level of the collecting duct of the nephron, thus inducing further hemodilution and hyponatremia, concomitantly with an inappropriately elevated urine osmolality (Uosm)1,2. In the less frequent Syndrome of Inappropriate Antidiuresis (SIAD), ADH secretion is inhibited, but an activating mutation of collecting duct V2 receptors imitates excessive ADH-induced water reabsorption3-5. Major advances have taken place over the last few years in our understanding of the negative consequences of hyponatremia. Mild, chronic hyponatremia is not asymptomatic. On the contrary, it is accompanied by mental symptoms, impaired gait, falls6, fractures7-9, and possibly osteoporosis10, as well as increased mortality9, 11-14. Severe hyponatremia per se can be life-threatening, inducing profound cerebral edema and potentially brain herniation and death. Even once hyponatremia is corrected, complete neurologic recovery can take weeks, and some patients will have permanent neurologic sequelae as a consequence of profound hyponatremia15. Yet overly rapid correction of serum sodium can induce osmotic demyelination syndrome (ODS). Adequate and prompt correction of hyponatremia is thus imperative, avoiding and/or dealing immediately with overcorrection, while assuring that eunatremia is ultimately achieved. Close to 30% of hospitalized patients are hyponatremic at some time during their hospital stay 13,16,17 , yet hyponatremia is often overlooked and undertreated, even in its most severe forms. A correct diagnosis of the cause of hyponatremia is per se associated with reduced inhospital mortality, as indicated by a lower death rate in patients with hyponatremia in whom plasma and/or urine Osmolality have been determined18. And specific treatment directed towards correcting hyponatremia is accompanied by a lower death rate.19 SIADH is considered to be the most frequent cause of hyponatremia in a hospital setting 20. However, detailed protocols and algorithms for its management are lacking. A new class of therapeutic agents, the vaptans, is currently available for the treatment of SIADH in the adult. They 440 Isabelle Runkle et al. Treatment of SIADH block the AVP-responsive V2 collecting duct receptors that ultimately induce apical expression of aquaporin 2 channels through which water is reabsorbed following AVP stimulus21. Tolvaptan is the only drug of its class authorized by the European Medicines Agency, and is a selective V2receptor blocker. Its addition to the therapeutic arsenal of 3% hypertonic saline solution, furosemide, solute, and fluid restriction further warrants a specific guide to the treatment of SIADH-induced hyponatremia. Our objective was to develop two consensus algorithms for the therapy of hyponatremia due to SIADH in hospitalized patients. These algorithms address acute correction of hyponatremia posing as a medical emergency (Algorithm 1) and correction of mild or moderate, nonacute hyponatremia requiring less aggressive measures (Algorithm 2). MATERIALS AND METHODS The algorithms were developed by a multidisciplinary group made up of 2 Endocrinologists, 2 Nephrologists, 2 Internists, and 1 Hospital Pharmacist. Over the period of a year, the group held meetings and worked on-line, organized under the auspices of the European Hyponatremia Network and the corresponding Spanish Medical Societies. Given the dearth of evidence in many aspects of the management of hyponatremia, we have based the algorithms we present on widely-accepted recommendations, expert opinion and consensus guidelines 22, as well as on the authors’ personal experience. Application of the protocol should be flexible, and adapted to the specific needs of each patient, as is always the case in clinical medicine. EXPLANATION OF THE ALGORITHMS AND THEIR USE The severity of the patient’s neurologic symptoms will be the most important element to be considered when choosing which algorithm to apply initially22, together with other factors presented in tables 1 and 2. Aggressive and prompt correction (Algorithm 1) is particularly important in subjects with acute and/or severe symptomatic hyponatremia indicative of substantial cerebral edema, in patients with hypoxemia23-28, in children and in women of child-bearing age27. When applying either algorithm, medication that can potentially cause hyponatremia must be discontinued when feasible. Pain and nausea are potent stimuli of AVP secretion and must be adequately treated. If the underlying cause of SIADH-induced hyponatremia is not evident, a Chest x-ray, brain, cervical and thoracic CT, and abdominal Nefrologia 2014;34(4):439-50 Isabelle Runkle et al. Treatment of SIADH Table 1. Definitions The Syndrome of Inappropriate Antidiuretic Hormone Secretion Euvolemic Hyponatremia : - Rule out a low effective circulating volume (normal OP, normal CVP, absence of orthostatic hypotension, ascites, and edema) - Rule out diuretic therapy - Rule out adrenal and renal failure, severe hypothyroidism - Rule out physiologic stimuli of ADH secretion (post-surgery, pain, etc.) and: -SNa < 135 mmol/L -Posm < 275 mOsm/Kg -Uosm > 100 mOsm/Kg -UNa > 40 mmol/L when sodium intake is adequate OP: ocular pressure; CVP: central venous pressure; SNa: serum sodium concentration; Posm: plasma osmolality; Uosm: urine osmolality; UNa: urine sodium concentration. ultrasound must be considered. If ordered, these diagnostic tests should follow initial emergency correction of SNa and improvement of patient’s symptoms if hyponatremia is severe. Application of Algorithm 1 In the setting of acute and/or severe hyponatremia with symptoms indicative of profound cerebral edema, the initial aim of this algorithm is reduction of said edema, while avoiding overcorrection of serum sodium. It is applicable to severe euvolemic or hypovolemic hyponatremia per se, regardless of the cause, and thus prior to diagnosis of its origin. The algorithm specifies initial treatment of cerebral edema with 3% hypertonic saline iv, monitoring of the subsequent rise in serum sodium concentration (S Na), and avoidance or treatment of overcorrection of hyponatremia. Hypertonic saline solution 1. 3% Hypertonic saline is the mainstay of treatment. The mainstay of therapy is the use of 3% hypertonic saline solution (HSS) administered iv 29 , to assure the movement of water from the intracellular to the intravascular compartment following an osmotic gradient, thereby reducing neuronal edema. A central Nefrologia 2014;34(4):439-50 special articles venous line is unnecessary and can only delay treatment. 3% saline, if unavailable, can be prepared by adding 60 ml of 20% saline to 500 ml of 0.9% isotonic saline. The resulting solution must be shaken before administration. Immediately prior to initiating treatment, blood must be drawn for determination of SNa, serum potassium (SK), urea, creatinine and plasma osmolality (P osm ). Urine for the determination of Na (U Na), K (U K) and U osm must be obtained as soon as possible, without delaying initiation of hypertonic saline administration. Hypoxemia must be ruled out and corrected if detected, since it worsens prognosis 23-28. Infusion rate. We propose an initial iv infusion rate of 3% HSS at 0.5 ml/Kg/hour or 1-2 ml/Kg/hour depending on the severity of the neurologic symptoms 30,31. Patients in coma, or presenting with seizures, stupor or respiratory distress, should be started on an initial infusion rate of 2 ml/Kg/hour In these patients, an alternative can be the administration of an iv bolus of 100 ml of 3% HSS, that can be readministered up to 2 more times at 10-minute intervals, and stopped once the acute symptoms have subsided 22,32. We do not advise the use of formulas to estimate the quantity and rate of infusion, since these calculations often lead to overcorrection 32-34 and can needlessly complicate therapy. As previously mentioned, treatment must be particularly aggressive in children and in women of child-bearing age 27 , given that their risk of severe hyponatremic encephalopathy is higher, potentially leading to subsequent brain herniation and death, or permanent neurologic sequelae. This is also the case for patients with acute hyponatremia. Patients who have recently ingested large quantities of liquid (acute water intoxication) are at special risk, since their neurologic symptoms and serum sodium will often worsen as they continue absorbing water from the gastrointestinal tract 35. We note that in these patients, sodium levels in arterial blood are often several mmol/L lower than in peripheral venous blood, and thus the latter can underestimate the true degree of hyponatremia36. HSS can induce substantial water diuresis, favoring overcorrection. Thus diuresis must be closely monitored to detect frank polyuria (urine output of approximately 2 ml/Kg/hour) and the need to initiate corrective measures directed towards relowering of SNa. These patients are also candidates to receive 1 mcg of sc or iv desmopressin directly upon detection of polyuria, thus preventing an excessive rise in serum sodium32,37. Specific treatment goals of hypertonic saline infusion. In the treatment of patients with chronic hyponatremia (of a duration of 48 or more hours), the maximum recommended rise in SNa is currently 10 mmol/L in 24 441 Isabelle Runkle et al. Treatment of SIADH special articles Table 2. Classification of hyponatremia according to severity of clinical symptoms Severe Symptoms Outlinea - - - - Moderate Stupor Coma Convulsions Respiratory Distress - - - - - Mild Nausea Vomiting Disorientation Somnolence Confusion - - - - - Headache Attention deficit Memory impairment Gait impairment Cognitive impairment Moderate/severe symptoms, usually: [SNa] < 120 mmol/L Mild/moderate symptoms, usually : [SNa] > 120 mmol/L See Algorithm 1: Acute therapy (medical emergency) See Algorithm 2: Non-acute therapy Therapeutic objective: Eunatremia (SNa > 135 mmol/L) - Factors that favor the use of Algorithm 1: Women of child-bearing age Children Brain tumors/hemorrhage Hypoxemia (pO2a < 70mmHg) SNa < 120 mmol/L Usually < 48 hours duration - Factors that favor the use of Algorithm 2: Malnutrition Hypokalemia Frail elderly SNa > 120 mmol/L Usually > 48 hours duration Laboratory evaluation: plasma and urine electrolytes and osmolality General therapy. Correct hypoxemia Consider the magnitude and speed of the reduction of SNa SNa; serum sodium concentration; pO2a; partial pressure of oxygen in arterial blood. a hours, and 18 mmol/L in 48 hours, to avoid the appearance of osmotic demyelination syndrome 22. Furthermore, a 4-6 mmol elevation in sodium levels is accompanied by a reduction in cerebral edema of the order of 50%38. A recent study found that patients presenting an initial SNa below 120 mmol/L had a higher mortality rate if their S Na rose less than 6 mmol/L over the first 24 hours of treatment 39 . Thus, our aim should be to achieve an increase in serum sodium of the order of 6 to 8 mmol over a 24-hour period. Avoiding overcorrection is particularly important in patients at a high risk of developing the osmotic demyelination syndrome such as alcoholics, patients who are malnourished, and those presenting hypokalemia 40-42. In these patients maximum correction rates should therefore be from 6 to 8 mmol/L and from 14 to16 mmol/L over 24 and 48 hours respectively. However, in patients with acute hyponatremia S Na can rise more quickly, without negative consequences. Monitoring and discontinuing hypertonic saline infusion. SNa should be repeated 2 hours after initiating HSS infusion. If sodium levels have risen more than 6 mmol/L, saline infusion must be stopped, since S Na can still rise after the infusion has been discontinued. If serum sodium has increased 1 to 6 mmol/L, infusion can be maintained at the same rate. If there is no increment in SNa , the infusion rate should be increased by 50-100%, taking into account the clinical status of the patient. If bolus therapy has been used, sodium levels should be monitored 30 minutes after the last bolus. No other treatments that raise serum sodium levels should be given concomitantly with hypertonic saline, with the SNa should once more be monitored 2 hours later (4 hours after initiation of saline infusion). If a patient has yet to 442 exception of iv furosemide in patients with a history of heart failure. Since the combination of hypertonic saline and a loop diuretic will increase sodium levels more than the use of hypertonic saline alone, the initial objective in these patients should be a rise in SNa of approximately 4-5 mmol/L with hypertonic saline infusion. Nefrologia 2014;34(4):439-50 Isabelle Runkle et al. Treatment of SIADH special articles Hyponatremia with moderate/severe symptoms and/or a duration ≤ 48 hours (SNa < 120 mmol/L) Hypertonic saline solution a,b,c Nacl 3% (513 Mmol/L) Severe symptoms 1-2 mL/kg/h or iv bolus 100 ml Moderate symptoms 0,5 mL/kg/h Evaluate 2 hours later SNa Increase < 1 mmol/L SNa Increase = 1-6 mmol/L Maintain infusion rate Increase infusion rate 50%-100% SNa Increase >6 mmol/L Stop hypertonic saline infusion Evaluate 2 hours later SNa < 120 mmol/L and/or SNa increase <2 mmol/L from start Severe symptoms SNa = 120-130 mmol/L and/or SNa increase >6 mmol/L from start Moderate symptoms Consider mantaining infusion rate and reevaluating 4-6 hours later Stop hypertonic saline infusion Reevaluate patient: - Clinical picture - Diagnostic studies - Complete lab work, imaging, etc. - Treat underlying disease SNa > 130 mmol/L and/or SNa increase >8 mmol/L from start Consider relowering SNa to avoid ODS: - Oral fluids - 5% dextrose solution (6 mL/kg/h during 2 hours) followed by measurement of Nap - Desmopressin 1-2 μg sc or iv q 6-8 hours Consider transition to Algorithm 2 Consider oral treatment Algorithm 1. Acute therapy. a,b Prepatation of 3% hypertonic saline solution: Add 60 ml of 20% NaCl saline solution to a 500 mL 0.9 % isotonic saline NaCl al 0,9%, and shake well. Administer vía peripheral vein; c Consider furosemida 20 mg iv (history of heart failure) Valorar transición SNa: serum sodium concentration; ODS: osmotic demyelination syndrome; SC: subcutaneous; IV: Intravenous a Algoritmo 2 present an increase of 2 mmol/L, and shows insufficient clinical improvement, the rate of saline infusion should again be increased, with SNa determined once more after two hours. If the patient presents only moderate or mild symptoms, the infusion rate can be maintained and SNa repeated 4-6 hours later. In patients whose SNa has risen over 6 mmol/L , saline infusion should be discontinued. If SNa has risen over 8 mmol/L, corrective measures should be initiated (see below). If the rise in SNa is between 2 Nefrologia 2014;34(4):439-50 and 6 mmol/L, infusion should be maintained, and S Na monitored every 2 hours until it has risen by 6 mmol/L. One of the most important recommendations we can make in the use of hypertonic saline is that the prescribing physician personally supervise cessation of the iv infusion. Once hypertonic saline infusion has been discontinued, and until 24 hours have passed since the start of treatment, 443 special articles oral salt can be administered and fluid restriction initiated in patients with SIADH. Other measures that can potentially raise SNa should be avoided, to decrease the risk of overcorrection. We include potassium chloride (KCl) in this category: mild hypokalemia should not be corrected until the following day, since KCl administration will increase serum sodium levels. Corrective Measures to Relower Serum Sodium Relowering of serum sodium, following an excessive rise, prevents ODS. The development of ODS has been associated with an excessive rise in serum sodium over a 24 or 48 hour period. ODS can induce death or leave permanent neurologic sequelae. It is for this very reason that the 2007 guidelines22 recommend a maximum serum sodium increment of 10 mmol/L and 18 mmol/L in 24 and 48 hours respectively. However, a rapid reinduction of hyponatremia has been shown to prevent ODS symptoms 37,43,44 and has been successfully used to treat patients that have developed ODS45-49. Specific Measures If S Na is overcorrected (S Na rise greater than 8 mmol/L following discontinuation of HSS or SNa rise greater than 10 mmol/L 24 hours after initiation of therapy), measures should be taken immediately to once again lower the SNa level. These include oral liquids, 5% iv dextrose solution (4-6 ml/Kg/hour for 2 hours with subsequent reevaluation of S Na) and 1-2 mcg iv or sc desmopressin every 6 hours if and as needed 37. When using desmopressin, we recommend a lower initial rate of dextrose infusion: 1.5 to 2 ml/Kg/hour, repeating SNa 2 hours later, and increasing the dextrose infusion rate as necessary. A lowering rate of 1 mmol/L/hour has been recommended50. The association of desmopressin to iv dextrose is particularly important in patients who will not otherwise reabsorb large quantities of water in the collecting duct, as is the case of patients with primary polydypsia, and other patients with low U osm. With low AVP levels, these patients will have few patent aquaporin-2 channels, (reflected by a low U osm) and desmopressin should be administered for dextrose infusion to be useful. Iv furosemide can be administered once the desired serum sodium level has been reached, to put a halt to a further reduction in SNa. Patients at high risk for overcorrection. Certain groups of patients present a higher risk of overcorrection of serum sodium than others, and must be more closely monitored. These include patients in which the cause of hyponatremia is transitory, e.g. hyponatremia-inducing medication which has just been discontinued, or physiologic stimuli of AVP secretion once the stimulus has passed32. Patients with an extremely low salt intake prior to admission also fall into this category. 444 Isabelle Runkle et al. Treatment of SIADH Patients with adrenal failure, either primary or secondary, are a separate case. They should receive high enough hydrocortisone doses to cover their glucocorticoid and mineralocorticoid needs. S Na can rise very quickly after initiation of steroid therapy, particularly if high doses of hydrocortisone are given, and especially if administered by iv bolus, as when treating an adrenal crisis. In these patients, if SNa rises by 8 mmol/L before 24 hours have elapsed since the start of treatment, 1-2 mcg of iv or sc desmopressin can be administered every 6-8 hours to prevent a further increment in S Na levels. In many patients, however, the infusion of lower doses of hydrocortisone will be sufficient (between 60-150 mg daily 51, with or without an intial bolus of 50 mg iv) and will induce a slower rate of correction of SNa levels. In even milder cases, oral hydrocortisone can be given at a dose of 20 mg tid. Application of Algorithm 2 The aim of algorithm 2 is to achieve eunatremia in patients with SIADH-induced mild or moderate hyponatremia not posing as a medical emergency. Correction of hypokalemia If hypokalemia is present, Potassium Chloride supplements should be given, taking care NOT to administer potassium bicarbonate, or potassium supplements that result in the generation of bicarbonate, since the latter will increase renal sodium excretion, and can induce metabolic alkalosis52. Solute Administration Patients with SIADH should have an adequate oral salt intake. A hospital diet frequently provides less than 4 grams of sodium chloride a day. Furthermore, many patients eat considerably less than what is provided, and will have an even lower sodium intake. We recommend the association of NaCl supplements, for a minimum consumption of 5 to 8 grams of salt daily. The administration of large amounts of solute can be used for the treatment of SIADH – induced hyponatremia, acting through the induction of increased renal obligatory water clearance. In this case, oral salt supplementation can range from 3 to 4 grams every 8 hours, and must be even higher in exceptional cases. Close monitoring of blood pressure is essential. Another solute that has been given for the treatment of SIADH hyponatremia is oral urea, at doses of 30 g a day, usually given in two 15 g doses 53. Urea could be the therapy of choice in children Nefrologia 2014;34(4):439-50 Isabelle Runkle et al. Treatment of SIADH with SIADH 54. However, its low palatability has limited its use. Fluid Restriction Currently, fluid restriction is the cornerstone of treatment of SIADH-induced hyponatremia not requiring urgent intervention. By fluid restriction we mean the reduction of all liquids administered to the patient, be it with iv medication, oral liquids, or the intrinsic water content of foods. To adequately initiate fluid restriction, iv medication must be concentrated whenever feasible, and non-essential oral and iv medication discontinued. Oral liquid intake must be limited and foods with a high water content eliminated from the diet (soups, mashed foods, coffee, tea, gelatins, semi-liquid desserts, melons, citric fruits, etc. ). In our experience, the Furst formula 55 is useful in predicting which patients will respond adequately, and is calculated by dividing the sum of U Na and U K (mmol/L) by SNa. Patients with a result less than 0,5 can be limited to 1000 ml of total liquid intake, whereas those between 0,5 and 1 need to be limited to 500 ml of liquid a day. Patients with a result of 1 or more will not respond to fluid restriction, since their nephrons are not capable of eliminating electrolyte-free water. In this case fluid restriction to 500 ml daily is used to prevent worsening of hyponatremia, not to correct it. The response of a specific patient to fluid restriction is not constant, and can vary from one day to another. Therefore, for a correct use of the Furst formula, electrolytes must be measured in serum and urine frequently. We consider a positive response to be an average 2 mmol/L rise in S Na per day over a 2-day period. Fluid restriction is not practical in all patients, and is simply incompatible with necessary medication or artificial nutrition in others. Another group does not tolerate or does not respond to the required fluid restriction. Furthermore, fluid restriction to 500 ml makes meals less palatable, and can worsen the nutritional status of the patient if used for more than a few days. In these cases, together with those presenting a Furst formula result of 1 or more, alternative therapies must be initiated. Furosemide Therapy Furosemide can be useful as a short-term treatment for SIADH hyponatremia when the UOsm is sufficiently high, as it induces an increase in renal free water clearance. For this loop diuretic to be effective, UOsm must be over 350 mOsm/Kg, and preferably over 400 mOsm/Kg. Sodium losses must be compensated by sufficient oral salt intake. Nefrologia 2014;34(4):439-50 special articles Furosemide can be administered iv or orally, in doses ranging from 20 mg iv every 8 to 24 hours, or 40 mg every 8 to 24 hours p.o., although higher doses have been successfully given56,57. The use of this loop diuretic is particularly helpful in patients in whom SIADH will presumably be of limited duration (days), as is the case of patients with pneumonia or drug-induced SIADH when the medication can be discontinued (table 3). Furosemide can also be useful in patients with serum sodium levels below 120 mmol/L presenting with moderate or mild symptoms, sodium levels higher that 115 mmol/L, and a low risk for herniation (ie the elderly). In this case serum sodium should be repeated 3 to 6 hours after an iv dose. Tolvaptan Therapy We recommend the use of tolvaptan, the selective V2 receptor inhibitor58, in patients with SIADH who are not candidates for fluid restriction or furosemide. The drug is particularly useful in patients that will need treatment of their hypotonic hyponatremia for several days, or longer, as occurs in patients with chronic SIADH. Initiation and monitoring of tolvaptan therapy. We prefer to start tolvaptan in patients in whose Nap has already risen above 119 mmol/L, since patients with lower serum sodium levels seem to be at a higher risk for overcorrection, in our experience as well as in that of others (Dr. Volker Burst, University of Cologne, personal communication). Tolvaptan therapy must always be initiated while the patient is hospitalized. Care should be taken to assure that during the first day of tolvaptan administration patients not only have free access to liquids, but also are actively encouraged to drink ad libitum, since maximum aquaresis is observed precisely on day 1, when excess circulating water is greatest. Patients who have previously been on fluid restriction are prone to not drinking as much as they desire and must be closely monitored. If a patient has a limited capacity to drink (ie oral or gastrointestinal disease) 5% dextrose solution should be associated from the start. Patients with a nasogastric tube will also need increased liquids. In these cases, diuresis is helpful in estimating increased fluid needs. The initial recommended dose is of 15 mg p.o., although several groups prefer to start treatment with 7.5 mg 59,60, (Dr. Volker Burst, personal communication). It is preferable to administer tolvaptan early in the morning (7 to 9 AM), to facilitate monitoring of the patient’s response, and to assure adequate nocturnal rest. We recommend measuring serum sodium, potassium and POsm as well as 445 Isabelle Runkle et al. Treatment of SIADH special articles Moderate/mild symptoms and/or hyponatremia > 48 hours Ensure minimum NaCl intake of 5 g p.o./day (SNa ≥ 120 mmol/L) (UNa+UK)/SNa <0.51 a (UNa+UK)/SNa > 1a (UNa+UK)/SNa = 0.51-1ª Fluid Restric. < 1000 ml/dayc Fluid Restric. Not Feasible b Fluid restric. < 500 ml/dayc Negative Response if SNa increases < 2 mmol/L in 24 hours 2 consecutive days. h f TOLVAPTAN 15 mg/day Discontinue fluid restrictiond,e Reevaluate 6 hours laterg,h SNa Increase ≤ 5 mmol/L from start SNa Increase >5 mmol/L Reevaluate 24 hours laterg,h Consider discontinuing treatment and taking corrective measures to avoid development of ODS - Oral fluids - 5% Dextrose solution iv (6 ml/kg/h during 2 hours) followed by measurement of SNa - Desmopressine 2 mcg SC o IV q.6.h. - Skip the next dose of tolvaptan Evaluate SNa increase and clincal status: SNa increase ≤ 0,4 mmol/L/h and SNa < 128 mmol/L or SNa increase ≤ 8 mmol/L from start Adapt TOLVAPTAN dose to responseg (if SNa < 135 mmol/L) TOLVAPTANhf 30 mg/day Reevaluate in 24 hours SNa Increase ≤ 5 mmol/L TOLVAPTAN 60 mg/day SNa Increase > 5 mmol/L Maintain TOLVAPTAN 30 mg/day Reevaluate in 24 hours Duration of treatment of SIADH based on etiology (table 3) Hospital discharge Follow-up 1 week later Follow-up 2-4 weeks later (consider etiology) and 1 week after discontinuation Algorithm 2. Non-acute treatment. a Furst H, et al. Am J Med Sci 2000;319(4):240-244; b Parenteral nutrition, or iv liquids that prevent fluid restricction, or patien intolerance; c Consider furosemide if Osmou >350 mOsm/Kg; d The patient must be able to drink ad libitum; e See warnings on text; f Tolvaptan summary of characteristics (Samsca®). Laboratorios Otsuka. g Measure electrolytes and Osmolality in plasma and urine; h Measure diuresis and liquid intake every 6 horas. If balance excessively negative: take corrective measures; especially important in patients with intial SNa< 125 mmol/L. Available at URL: http://www.ema.europa.eu. Access: November 2011. SNa: serum sodium concentration; UNa and UK =Urine concentrations of sodium and potassium mmol/L; Osmou: urine osmolality; ODS: osmotic demyelination syndrome; SC: subcutaneous; IV: intravenous; SIADH: syndrome of inappropriate antidiuretic hormone secretion. 446 Nefrologia 2014;34(4):439-50 Isabelle Runkle et al. Treatment of SIADH special articles sodium, potassium and osmolality in urine at baseline, and 6 hours after the initial dose, with monitoring of fluid intake and diuresis every 6 hours. Patients whose S Na has not increased by more than 5 mmol/L at 6-hours post-tolvaptan, and are drinking freely can be monitored by fluid intake/diuresis alone, with SNa repeated 24 hours after the initial dose. If at 6 hours from baseline, SNa has risen more than 5 mmol/L, we recommend initiating corrective measures in order to prevent an excessive rise in the 24-hour serum sodium levels, , given that in our experience on day one of tolvaptan therapy S Na will rise at nighttime, when the patient`s fluid intake is low. These measures include an increase in oral fluid intake, and 5% dextrose solution iv infusion, at a rate of 3-4 ml/Kg/hour for 2 hours, followed by a new determination of SNa. We have found the association of desmopressin (iv or sc) to be useful in avoiding overcorrection of S Na in spite of V2 blockade, at doses of 2-4 mcg every 6 hours as needed. When using desmopressin, we recommend starting with a lower rate of dextrose infusion: 2 3ml /Kg/hour for 2 hours, followed by measurement of S Na. The rate of infusion is then increased every 2 hours as necessary to relower sodium levels , with a goal of attaining a maximum increment of 4 mmol/L over baseline. Patients whose SNa has risen more than 5 mmol/L over the first 6 hours should have S Na measured once more 12 hours from baseline. Not all patients drink as needed and thus some present a excessively negative fluid balance. They will also require a new 12 h measurement of SNa. If 24 hours following the first dose serum sodium levels have increased more than 10 mmol/L, tolvaptan should not be readministered on that day, and corrective measures used as needed, although discontinuation of tolvaptan administration is usually sufficient to relower S Na to desired levels. The drug can be reintroduced on the following day. If SNa has increased by less than 10 mmol/L, a new dose of 15 mg should be administered, and S Na monitored on the following day. When the rise in serum sodium levels is insufficient, the daily dose of tolvaptan can be increased to 30 mg, with a maximum dose of 60 mg/day. Experience with tolvaptan in Europe is still somewhat limited, and its use will surely undergo modifications in the future, particularly regarding doses. Table 3. Probable duration of syndrome of inappropriate antidiuretic hormone secretion treatment as indicated by etiology Etiology Probable duration of SIADH ADH-secreting tumors (ectopic SIADH) (oat-cell, etc.) Function of the duration of the underlying disease Medication-induced, with continued use of the drug (carbamazepine, etc.) Duration of treatment Relative Risk of chronic SIADH 1.0 1.0 Cerebral tumors Function of the evolution of the underlying disease 0.8 Idiopathic SIADH of the elderly Indefinite 0.8 Subarachnoid Hemorrhage 1-4 weeks 0.6 Stroke 1-4 weeks 0.5 Inflammatory Cerebral Lesions Function of response to therapy 0.5 Respiratory Failure (COPD) Function of response to therapy 0.4 HIV Infection Function of response to therapy 0.2 Head Trauma From 2-7 days to indefinite 0.2 Drug-induced, when the medication is discontinued. (carbamazepine, etc.) Function of the duration of treatment 0.1 Pneumonia 2-5 days 0 Nausea, pain, prolonged exercise Variable, depends on the cause 0 Post-operative Hyponatremia 2-3 days 0 COPD: chronic obstructive lung disease; SIADH: Syndrome of onappropriate Antidiuretic Hormone Secretion; HIV: human immunodeficiency virus. Repoduced with author’s permission from Verbalis J. Managing patients with syndrome of inappropriate antidiuretic hormone secretion. Endocrinol Nutr 2010;57(supl.2):30-40. Nefrologia 2014;34(4):439-50 447 special articles Isabelle Runkle et al. Treatment of SIADH Tolvaptan: General Considerations. Tolvaptan has important drug interactions which must be taken into account before and during its use (Table 4). As a substrate for cytochrome P450 3A4, circulating levels of tolvaptan will increase when used with inhibitors, and will drop when associated with inducers. Tolvaptan at high doses (60 mgday) can increase serum digoxin concentrations. of more research directed towards gathering evidence that can optimize therapy. Tolvaptan should be used as monotherapy for SIADH, and never be administered jointly with hypertonic saline. On day 1 of use, it is preferable not to associate potassium supplements, nor furosemide. Tolvaptan should never be administered to a hypovolemic patient, underlying the importance of a correct diagnosis of SIADH. Tolvaptan is usually well tolerated, and in our experience is very effective for attaining strict eunatremia. However, intense thirst sometimes follows its administration. When accompanied by the ingestion of large quantities of liquid, thirst can lessen the effectiveness of the medication, as can chronic pain. Patients with SIADH type D (NSIAD due to an activating V2 receptor mutation) will probably not respond to tolvaptan treatment 61. Conflicts of interest Duration of Treatment. Out-patient follow-up. The duration of tolvaptan treatment is determined by the persistence of the underlying cause of the patient’s SIADH (Table 3). When discontinuing tolvaptan, a progressive reduction in dose is always preferable to abrupt withdrawal of the medication. In patients discharged on tolvaptan therapy, we recommend repeating SNa within a week, with new laboratory tests 2 to 4 weeks later, then monthly. In patients with chronic SIADH, in our experience, the tolvaptan dose can be progressively reduced once strict eunatremia is achieved. Patients with particularly low maintenance doses of tolvaptan may need higher doses once more in situations of increased liquid administration, and /or low salt intake, such as typically occurs with hospital readmission. CONCLUSIONS Hyponatremia is a very common disorder, yet it remains underdiagnosed, underappreciated, and often incorrectly managed. Concrete roadmaps for the treatment of hyponatremic patients are lacking. We have elaborated two complementary strategies to treat SIADH-induced hyponatremia in an attempt to increase awareness of its importance, simplify its therapy, and improve prognosis. In spite of the frequency and negative repercussions of hyponatremia, there is a paucity of evidence in the field of hyponatremia and its therapy. We are clearly in need 448 We hope that the application of this protocol will simplify and help bring consistency to the treatment of SIADH-induced hyponatremia, thus reducing morbidity, and facilitating the accumulation of evidence. Isabelle Runkle has worked as a consultant for Otsuka and has given sessions sponsored by Otsuka, Amgen and Novartis. Carles Villabona has worked as a consultant for Otsuka and has given sessions sponsored by Novartis, Ipsen and Otsuka. Andrés Navarro has worked as a consultant for Otsuka. Antonio Pose has worked as a consultant for Otsuka, Boehringer, MSD, Rovi and Almirall, and has given sessions sponsored by Otsuka, Almirall, Boehringer, Novartis, Astra, Bristol, Lilly, Bayer, Sanofi, Lacer and Novo. Francesc Formiga has worked as a consultant for Otsuka and has given sessions sponsored by Otsuka. Alberto Tejedor has worked as a Nephrology consultant for the Spanish Agency of Medicines and the European Medicines Agency. He has been a consultant for Otsuka and Astra Zeneca. Esteban Poch has worked as a consultant for Otsuka and has given sessions sponsored by Otsuka. Table 4. Tolvaptan drug interactions - Tolvaptan should be administerd with caution when used together with CYP3A4 inhibidores (such as ketoconazol, diltiazem, macrolides) since these drugs increase circulating levels of tolvaptan. - Tolvaptan action is reduced when co-administered with CYP3A4 inducers (such as rifampicine, barbiturates) as well as when co-administered with cylcosporine. - Grapefruit juice can increase the activity of tolvaptan, and should be avoided. - No interactions have been observed with CYP3A4 substrates (such as warfarin or amiodarone). - Circulating levels of lovastatin are increased. - Doses of 60 mg increase digoxin levels, requiring that the latter be measured. Nefrologia 2014;34(4):439-50 Isabelle Runkle et al. Treatment of SIADH special articles REFERENCES 1. Schwartz W, Bennett W, Curelop S, Bartter FC. A syndrome of renal sodium loss and hyponatremia probably resulting from inappropriate secretion of antidiuretic hormone. Am J Med 1957;23:529-42. 2. Bartter FC, Schwartz WB. The syndrome of inappropriate secretion of antidiuretic syndrome. Am J Med 1967;42:790-806. 3. Feldman BJ, Rosenthal SM, Vargas GA, Fenwick RG, Huang EA, Matsuda-Abedini M, et al. Nephrogenic syndrome of inappropriate antidiuresis. N Engl J Med 2005;352:1884-90. 4. Zerbe R, Stropes L, Robertson GL. Vasopressin function in the syndrome of inappropriate antidiuresis. Annu Rev Med 1980;31:315-27. 5. Robertson GL. Regulation of arginine vasopressin in the syndrome of inappropriate antidiuresis. Am J Med 2006;119:S36-S42. 6. Renneboog B, Musch W, Vandemergel X, Manto MU, Decaux G. Mild chronic hyponatremia is associated with falls, unsteadiness, and attention deficits. Am J Med 2006;119:71.e1-8. 7. Gankam Kengne F, Andres C, Sattar L, Melot C, Decaux G. Mild hyponatremia and risk of fracture in the ambulatory elderly. QJM 2008;101:583-8. 8. Sandhu HS, Gilles E, DeVita MV, Panagopoulos G, Michelis MF. Hyponatremia associated with large-bone fracture in elderly patients. Int Urol Nephrol 2009;41:733-7. 9. Hoorn EJ, Rivadeneira F, van Meurs JB, Ziere G, Stricker BH, Hofman A, et al. Mild hyponatremia as a risk factor for fractures: the Rotterdam Study. J Bone Miner Res 2011;26:1822-8. 10. Verbalis J, Barsony J, Sugimura Y, Tiang Y, Adams D, Carter E, et al. Hyponatremia-induced osteoporosis. J Bone Miner Res 2010;25:554-63. 11.Anderson RJ, Chung HM, Kluge R, Schrier RW. Hyponatremia: a prospective analysis of its epidemiology and the pathogenetic role of vasopressin. Ann Intern Med 1985;102:164-8. 12.Waikar SS, Mount DB, Curhan GC. Mortality after hospitalization with mild, moderate, and severe hyponatremia. Am J Med 2009;122:857-65. 13.Wald R, Jaber BL, Price LL, Upadhyay A, Madias NE. Impact of hospital-associated hyponatremia on selected outcomes. Arch Intern Med 2010;170:294-302. 14. Sajadieh A, Binici Z, Mouridsen MR, Nielsen OW, Hansen JF, Haugaard SB. Mild hyponatremia carries a poor prognosis in community subjects. Am J Med 2009;122:679-86. 15. A rieff A. Hyponatremia, convulsions, respiratory arrest, and permanent brain damage after elective surgery in healthy women. N Engl J Med 1986;314:1529-35. 16. Upadhyay A, Jaber B, Madias N. Incidence and prevalence of hyponatremia. Am J Med 2006;119:S30-S35. 17. Hawkins RC. Age and gender as risk factors for hyponatremia and hypernatremia. Clin Chim Acta 2003;337:169-72. 18.Whyte M, Down C, Miell J, Crook M. Lack of laboratory assessment of severe hyponatremia is associated with detrimental clinical outcomes in hospitalized patients. Int J Clin Pract 2009;63:1451-5. 19. Hoorn E, Lindemans J, Zeitse R. Development of severe hyponatremia in hospitalized patients: treatment-related risk factors and inadequate management. Nephrol Dial Transplant 2006;21:70-6. 20. Ellison D, Berl T. The syndrome of inappropriate antidiuresis. N Engl J Med 2007;356:2064-72. 21. Rozen-Zvi B, Yahav D, Gheorghiade M, Korzets A, Leibovici L, Gafter U. Vasopressin receptor antagonists for the treatment of Nefrologia 2014;34(4):439-50 hyponatremia: systematic review and meta-analysis. Am J Kidney Dis 2010;56:325-37. 22. Verbalis J, Goldsmith S, Greenberg A, Schrier R, Sterns R. Hyponatremia treatment guidelines 2007: Expert panel recommendations. Am J Med 2007;120:S1-S21. 23.Vexler ZS, Ayus JC, Roberts TP, Fraser CL, Kucharczyk J, Arieff AI. Ischemic and hypoxic hypoxia exacerbate brain injury associated with metabolic encephalopathy in laboratory animals. J Clin Invest 1994;93:256-64. 24.Ayus JC, Arieff AI. Pulmonary complications of hyponatremic encephalopathy: noncardiogenic pulmonary edema and hypercapnic respiratory failure. Chest 1995;107:517-21. 25.Ayus JC, Arieff AI. Chronic hyponatremic encephalopathy in postmenopausal women: association of therapies with morbidity and mortality. JAMA 1999;281:2299-304. 26. Ayus JC, Armstrong D, Arieff AI. Hyponatremia with hypoxia: Effects on brain adaptation, perfusion, and histology in rodents. Kidney Int 2006;69:1319-25. 27.Arieff A. Influence of hypoxia and sex on hyponatremic encephalopathy. Am J Med 2006;119:S59-S64. 28. Nzerue C, Baffoe-Bonnie H, You W, Falana B. Predictors of outcome in hospitalized patients with severe hyponatremia. J Natl Med Assoc 2003;95:335-43. 29.Ayus JC, Olivera J, Frommer J. Rapid correction of severe hyponatremia with intravenous hypertonic saline solution. Am J Med 1982;72:43-8. 30. Rose B. Treatment of hyponatremia. UpToDate 2000. Available at: http://cmbi.bjmu.edu.cn/uptodate/critical care/Fluid and electrolyte disorders/Treatment of hyponatremia- Sodium deficit and rate of correction.htm. 31. Rose B. Treatment of Hyponatremia. UpToDate edition 17, 2010. 32. Sterns R, Nigwekar SU, Hix JK. The treatment of hyponatremia. Sem Nephrol 2009;29:282-99. 33. M oritz M, Ayus JC. The pathophysiology and treatment of hyponatraemic encephalopathy: an update. Nephrol Dial Transplant 2003;18:2486-91. 34. Schrier RW, Bansal S. Diagnosis and management of hyponatremia in acute illness. Curr Opin Crit Care 2008;14:627-34. 35. Cherney DZ, Davids MR, Halperin ML. Acute hyponatraemia and ‘ecstasy’: insights from a quantitative and integrative analysis. QJM 2002;95:475-83. 36. Shafiee MA, Charest AF, Cheema-Dhadli S, Glick DN, Napolova O, Roozbeh J, et al. Defining conditions that lead to the retention of water: the importance of the arterial sodium concentration. Kidney Int 2005;67:613-21. 37. Perianayagam A, Sterns R, Silver S, Grieff M, Mayo R, Hix J, et al. DDAVP is effective in preventing and reversing inadvertent overcorrection of hyponatremia. Clin J Am Soc Nephrol 2008;3:331-6. 38. Koenig MA, Bryan M, Lewin JL, Mirski MA, Geocadin RG, Stevens RD. Reversal of transtentorial herniation with hypertonic saline. Neurology 2008;70:1023-9. 39. Kang SH, Kim HW, Lee SY, Sun IO, Hwang HS, Choi SR, et al. Is the sodium level per se related to mortality in hospitalized patients with severe hyponatremia? Clin Nephrol 2012;77:182-7. 449 special articles 40. K arp BI, Laureno R. Pontine and extrapontine myelinolysis: a neurologic disorder following rapid correction of hyponatremia. Medicine (Baltimore) 1993;72:359-73. 41. Ashrafian H, Davey P. A review of the causes of central pontine myelinolysis: Yet another apoptotic illness? Eur J Neurol 2001;8:103-9. 42. Kleinschmidt-Demasters BK, Rojiani AM, Filley CM. Central and extrapontine myelinolysis: then… and now. J Neuropathol Exp Neurol 2006;65:1-11. 43. Soupart A, Penninckx R, Crenier L, Stenuit A, Perier O, Decaux G. Prevention of brain demyelination in rats after excessive correction of chronic hyponatremia by serum sodium lowering. Kidney Int 1994;45:193-200. 44. Gankam Kengne F, Soupart A, Pochet R, Brion JP, Decaux G. Re-induction of hyponatremia after rapid overcorrection of hyponatremia reduces mortality in rats. Kidney Int 2009;76:61421. 45. Soupart A, Penninckx R, Stenuit A, Perier O, Decaux G. Reinduction of hyponatremia improves survival in rats with myelinolysis-related neurologic symptoms. J Neuropathol Exp Neurol 1996;55:594-601. 46. Soupart A, Ngassa M, Decaux G. Therapeutic relowering of the serum sodium in a patient after excessive correction of hyponatremia. Clin Nephrol 1999;51:383-6. 47. Oya S, Tsutsumi K, Ueki K, Kirino T. Reinduction of hyponatremia to treat central pontine myelinolysis. Neurology 2001;57:1931-2. 48.Croxson M, Lucas J, Bagg W. Diluting delirium. N Z Med J 2005;118:U1661. 49. Yamada H, Takano K, Ayuzawa N, Seki G, Fujita T. Relowering of serum Na for osmotic demyelinating syndrome. Case reports in neurological medicine 2012;2012:704639. 50. Sterns R, Emmett M, Forman J. Osmotic demyelination syndrome and overly rapid correction of hyponatremia. UpToDate 2012. 51. Nieman L, Lacroix A, Martin K. Treatment of adrenal insufficiency in adults. UpToDate 2012. Isabelle Runkle et al. Treatment of SIADH 52. Lindinger MI, Franklin TW, Lands LC, Pedersen PK, Welsh DG, Heigenhauser GJ. NaHCO(3) and KHCO(3) ingestion rapidly increases renal electrolyte excretion in humans. J Appl Physiol 2000;88:540-50. 53. Decaux G, Brimouille S, Genette F, Mockel J. Treatment of the syndrome of inappropriate secretion of antidiuretic hormone by urea. Am J Med 1980;69:99-106. 54. Huang EA, Feldman BJ, Schwartz ID, Geller DH, Rosenthal SM, Gitelman SE. Oral urea for the treatment of chronic syndrome of inappropriate antidiuresis in children. J Pediatr 2006;148:128-31. 55. Furst H, Hallows KR, Post J, Chen S, Kotzker W, Goldfarb S, et al. The urine/plasma electrolyte ratio: A predictive guide to water restriction. Am J Med Sci 2000;319:240-4. 56. D ecaux G, Waterlot Y, Genette F, Hallemans R, Demanet JC. Inappropriate secretion of antidiuretic hormone treated with furosemide. Br Med J (Clin Res Ed) 1982;10:89-90. 57.Decaux G. Treatment of the syndrome of inappropriate secretion of antidiuretic hormone by long loop diuretics. Nephron 1983;35:82-8. 58. Verbalis JG, Alder S, Schrier RW, Berl T, Zhao Q, Czerwiec FS; SALT Investigators. Efficacy and safety of oral tolvaptan therapy in patients with the syndrome of inappropriate antidiuretic hormone secretion. Eur J Endocrinol 2011;164:725-32. 59. Gross P, Wagner A, Decaux G. Vaptans are not the mainstay of treatment in hyponatremia: perhaps not yet. Kidney Int 2011;80:594600. 60. C uesta M, Gomez-Hoyos E, Montañez C, Martin P, Marcuello C, de Miguel P, et al. An initial dose of 7.5 mg Tolvaptan is safe and effective in the treatment of hyponatremia caused by SIADH. Presented at ECE/ICE. Florence, Italy. May 2012. 61. Decaux G, Vandergheynst F, Bouko Y, Parma J, Vassart G, Vilain C. Nephrogenic syndrome of inappropriate antidiuresis in adults: High phenotypic variability in men and women from a large pedigree. J Am Soc Nephrol 2007;18:606-12. Sent to review: 1 Sep. 2013 | Accepted: 14 Apr. 2014 450 Nefrologia 2014;34(4):439-50 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society originals Predictive factors for kidney damage in febrile urinary tract infection. Usefulness of procalcitonin Elena Lucas-Sáez1, Susana Ferrando-Monleón2, Juan Marín-Serra3, Ricardo Bou-Monterde4, Jaime Fons-Moreno5, Amelia Peris-Vidal6, Aurelio Hervás-Andrés7 1 Departamento de Pediatría. Hospital de Manises. Valencia (Spain); 2 Departamento de Pediatría. Hospital La Ribera. Alzira, Valencia (Spain); 3 Departamento de Pediatría. Hospital Clínico Universitario de Valencia (Spain); 4 Unidad de Epidemiología. Hospital La Ribera. Alzira, Valencia (Spain); 5 Departamento de Pediatría. Hospital Clínico Universitario de Valencia. Universidad de Valencia (Spain); 6 Servicio de Pediatría. Centro de Salud Serreria II. Valencia (Spain); 7 Departamento de Pediatría. Hospital Lluís Alcanyís. Xátiva, Valencia (Spain) Nefrologia 2014;34(4):451-7 doi:10.3265/Nefrologia.pre2014.Apr.12467 Objective: To establish the utility of procalcitonin (PCT) and other clinical and analytical parameters as markers of acute and permanent renal damage in children after a first febrile urinary tract infection (UTI). Methods: Retrospective multicentre study. Statistical study: descriptive, receiver operating characteristic (ROC) curves and multiple logistic regression. Results: 219 patients, aged between 1 week and 14 years (68% under 1 year). The mean PCT values were significantly higher in patients with acute pyelonephritis with respect to normal acute DMSA (4.8 vs 1.44; P=0.0001), without achieving that signification for late affected DMSA (6.5 vs 5.05; P=0.6). The area under the ROC curve for PCT was 0.64 (CI 95% 0.55-0.72) for acute renal damage, and 0.62 (CI 95% 0.44-0.80) for permanent damage, with optimum statistical cut-off values of 0.85 and 1.17ng/ml. Multivariate analysis for acute renal damage only found correlation with PCT (Odds Ratio [OR] 1.2 (CI 95% 1.06-1.4, P=0.005), and hours of fever (OR for less than 6 hours of fever 0.4 (CI 95% 0.2-1.02, P=0.05). In patients with renal scarring, PCT showed an OR 1.0 (CI 95% 0.9-1.1, P=0.6). Conclusions: PCT and the duration of fever were the only parameters statistically associated with early renal damage. PCT and renal scarring did not reach statistical significance. Factores predictivos de daño renal en la infección febril del tracto urinario. Utilidad de la procalcitonina RESUMEN Objetivo: Establecer la utilidad de la procalcitonina (PCT) y otros parámetros clínicos y analíticos como indicadores de daño renal agudo y permanente en niños tras una primera infección del tracto urinario (ITU) febril. Material y métodos: Estudio retrospectivo multicéntrico. Estudio estadístico: descriptivo, curvas ROC y regresión logística múltiple. Resultados: 219 pacientes, con edades entre 1 semana y 14 años (68 % menores de 1 año). Las medias de PCT fueron significativamente mayores en pacientes con pielonefritis aguda respecto a aquellos con DMSA agudo normal (4,8 frente a 1,44; p = 0,0001), sin alcanzar significación para DMSA tardío (6,5 frente a 5,05; p = 0,6). El área bajo la curva ROC de PCT fue 0,64 (IC 95 % 0,55-0,72) para daño renal agudo y 0,62 (IC 95 % 0,44-0,80) para permanente; con puntos de corte óptimos de 0,85 y 1,17 ng/ml. El análisis multivariante para daño renal agudo solo encontró correlación con PCT (odds ratio [OR] 1,2, IC 95 % 1,06-1,4; p = 0,005) y horas de fiebre (OR para < 6 h 0,4, IC 95 % 0,2-1,02; p = 0,05). En los pacientes con cicatriz, la OR para PCT fue 1,0 (IC 95 % 0,9-1,1; p = 0,6). Conclusiones: La PCT y la duración de la fiebre fueron los únicos parámetros que se asociaron de forma significativa a daño parenquimatoso agudo. No se observó relación estadísticamente significativa entre la PCT y la cicatriz renal. Keywords: Procalcitonin. Acute renal damage. Permanent renal damage. Febrile urinary tract infection. Palabras clave: Procalcitonina. Daño renal agudo. Daño renal permanente. Infección urinaria febril. ABSTRACT INTRODUCTION Urinary tract infection (UTI) is one of the most common bacterial infections in children, with an overall incidence of 3%-7%1-5. Correspondence: Elena Lucas Sáez Departamento de Pediatría. Hospital de Manises. Av. Generalitat Valenciana 50, 46940. Manises. Valencia. (Spain) [email protected] [email protected] Lack of symptom specificity in younger patients, frequent association with malformations of the urinary tract and the possibility of permanent renal damage require multiple complementary tests in daily practice. There is no consensus in clinical practice protocols and guidelines concerning the complementary examinations that should be carried out following a first episode of febrile UTI and which patients are at a greater risk of developing renal scarring4-8. 451 originals Currently, renal scintigraphy with Tc 99m dimercaptosuccinic acid (DMSA) is the gold standard for diagnosing acute and permanent kidney damage9,10. However, this test is expensive, is not available in all centres and requires the patient to undergo radiation. Consequently, there is an attempt to find an indicator that limits invasive tests to those patients at greater risk. Various molecules have been proposed as possible markers for renal damage. Several studies have shown their usefulness for interleukin (IL)-6, IL-8 and urine osmolality, a more discreet usefulness for α tumour necrosis factor, N-acetylglucosamine and IL-16, and low or no usefulness for other tubular proteins11-13. In recent years, the most studied marker was procalcitonin (PCT), due to its rapid and specific response to serious bacterial infections 14,15. It is a precursor of calcitonin without hormone activity, with practically undetectable values in physiological conditions and during viral infections, and which increases rapidly and proportionally in response to bacterial infection and its severity. The increase occurs 2 hours after the onset of the infection, reaches its maximum level at 12 hours and normalises in 2-3 days when the infection has subsided. There are diverse studies concerning the usefulness of PCT for diagnosing acute and chronic renal damage, whose results are contradictory 16-27. The objective of our study was to assess the usefulness of PCT and other analytical (leukocytes, C-reactive protein [CRP], etc.) and clinical (age, hours of fever, etc.) parameters as indicators of acute and permanent renal damage in children after their first episode of febrile UTI. MATERIAL AND METHOD It is a retrospective multicentre study carried out in four hospitals in Valencia (Spain), collecting data from paediatric patients admitted during their first episode of febrile UTI, from 2006-2010. Inclusion criteria were UTI diagnosis through positive urine culture with a significant number of colonies according to the collecting method, fever over 38ºC, leukocyte count above the upper value of the normal range according to age and/or CRP levels > 30 mg/l, with at least one PCT measurement and previous early or late DMSA. Those patients with known uropathy (including prenatal ectasia) and those with a previous febrile UTI episode were excluded. The study was approved by the Ethics Committees of the participating hospitals. 452 Elena Lucas-Sáez et al. Procalcitonin, predictor of kidney damage We recorded each patient’s clinical data (age, sex, fever duration until blood analysis, highest fever reached and related symptoms), the antibiotic treatment used and the hours it took the patient to become afebrile following the onset of that treatment. Analytical data included: leukocyte and neutrophil count, CRP and PCT values, urine collection method, bacterium identified in the urine culture, antibiotic sensitivity and the same bacterium’s presence or absence in the haemoculture. The method for measuring PCT during the first years of the study was semi-quantitative using the immunochromatographic BRAHMS test (36 patients), and later using the BRAHMS Kryptor compact electrochemiluminescence immunoassay method (183 patients). Only quantitative PCT values were used for the statistical analysis. Regarding the imaging tests, we collected results from the conventional ultrasound and acute and/or late phase DMSA. The scintigraphic study was performed 3 hours after injecting a weight-adjusted TC-DMSA dose, obtaining three planes. The presence of focal or diffuse areas of uptake defects, without evidence of cortical loss, was considered pathological. In those cases in which cystography was performed (either early pathological DMSA or dilation of the upper urinary tract detected in ultrasound during admission), we recorded the presence or absence of vesicoureteral reflux (VUR), the degree and the uni/bilaterality. Statistical analysis included the calculation of sensitivity (S), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and calculation of the area below the ROC curve. The χ2 test and the Student’s t-test were performed to compare the categoric and quantitative variables, respectively. Non-conditional logistic regression was used to estimate the association between the variables of interest. RESULTS A total of 219 patients (131 girls and 88 boys) were included in the study, aged between 1 week and 14 years, of which 149 (68%) were younger than 1 and 18 were younger than 28 days (8.2%). The median value of the fever’s development in hours when performing blood analysis was 24 [1-96] and the most common associated symptoms were gastrointestinal. As regards the analytical results, the leukocyte median was 18,000/mm3 (3,900-41,600), CRP median 74mg/l (4.469) and PCT median 1.16ng/ml (0.07-53.5) (Table 1). The tendency for PCT medians to increase in patients with normal and pathological DMSA, both in acute and late phase, is shown in Figure 1. Nefrologia 2014;34(4):451-7 Elena Lucas-Sáez et al. Procalcitonin, predictor of kidney damage The most common isolated bacterium was Escherichia coli in 92.7% of cases. Other bacteria were isolated in 16 patients (7.3%): 4 klebsiella (25%), 3 Proteus, 3 enterobacteriaceae, 2 enterococci and 2 Citrobacter and 2 others. 7.5 In those patients with early pathological DMSA, late DMSA was indicated a mininum of 9 months after performing the previous DMSA. The presence of renal scarring was interpreted in this context as secondary to acute damage, however these changes may not necessarily be due to the Table 1. Description of clinical and analytical data Age 7 days – 14 years Sex (M/F) 88/131 Fever duration (hours), median and range 24 (1-196) Related symptoms n (%) Fever 219 (100%) Vomiting or diarrhoea 88 (40%) Irritability 29 (13%) Urinary disorders 22 (10%) Lumbar pain 9 (4%) Analytical data (median and range) Leukocytes (/mm3) 18,000 (3,900-41,600) CRP (mg/l) 74 (4-469) PCT (ng/ml) 1.16 (0.07-53.5) CRP: C-reactive protein; PCT: procalcitonin. Nefrologia 2014;34(4):451-7 3.0 0.0 Normal Pathological Late DMSA 12.5 Procalcitonin Acute-phase DMSA was performed on all patients in the first 7 days after admission (late DMSA alone was performed on 2 patients); 142 patients presented alterations (64.8%). In the cases with infection by a bacterium other than E. coli, the percentage of scintigraphic acute-phase alterations was 53%. 4.5 1.5 The antibiotic guideline chosen in the majority of cases was intravenous gentamicin (65%), with a mean fever disappearance time of 32 hours after the onset of treatment. Conventional ultrasound was performed on all patients, with 60 (27%) presenting disorders. Doppler Sonography was carried out simultaneously in some centres (72 sonographs, 22 pathological alterations). Acute DMSA 6.0 Procalcitonin The urine collection method in continent patients was via midstream sampling. An adhesive bag was used on 60 incontinent patients (35%), always obtaining two samples, and a sterile technique was used on the remainder (urinary catheterisation or suprapubic aspiration). originals 10.0 7.5 5.0 2.5 0.0 Normal Pathological Figure 1. Procalcitonin values in patients with normal and pathological dimercaptosuccinic acid in acute phase (acute pyelonephritis) and late phase (scarring) DMSA: dimercaptosuccinic acid. The lower and upper limits of the box indicate the 25 and 75 percentiles. The line crossing the box is the median. cause-effect of early injury. This was carried out on 99 patients, with 22 resulting pathological (22.8%). Cystography was performed on 126 patients, of which 30 (23.8%) were diagnosed with VUR. The most significant clinical and analytical data in children with acute-phase pathological DMSA (acute pyelonephritis) and in those with normal DMSA are recorded in Table 2. PCT means were significantly higher in patients with acute-phase pathological DMSA in respect to those unaffected (4.8 vs 1.44; P=.0001); this significance was not achieved for late DMSA (6.5 vs 5.05; P=.6). Similarly, CRP averages behaved with respect to early DMSA (112.8 vs. 70.24; P=.01) and late DMSA (163.39 vs. 115; P=.06). 453 Elena Lucas-Sáez et al. Procalcitonin, predictor of kidney damage originals The area below the PCT ROC curve for acute renal damage was 0.64 (95% CI 0.55-0.72) and 0.62 for scarring (95% CI 0.44-0.80), establishing values of 0.85 and 1.17ng/ml as cutoff points (Figures 2 and 3). The values of S, Sp, PPV and NPV for acute and chronic renal damage are presented in tables 3 and 4, respectively. Although the characteristics of the newborn subgroup may differ to those of the rest of the study’s population, we decided to include this group to maintain the homogeneity of the participating centres and to guarantee, as far as possible, sufficient statistical power in order to establish statistically significant associations. The multivariate analysis with respect to acute renal damage only found association with PCT (Odds Ratio [OR] 1.2, 95% CI 1.06-1.4; P=.005) and fever duration (OR for <6h 0.4, 95% CI 0.2-1.02; P=.05). Patients younger than one year presented lower risk of scinitgraphic affectation, although statistic significance was not achieved (OR 0.52, 95% CI 0.2-1.1; P=.08). Despite the causal bacterium being E. coli in the majority of patients, other bacteria were discovered in 16 of the study population. It involves 8 males and 7 females, which constitute 7% of the sample’s total, of which 9 (56%) were younger than 1 year. Fever duration was <24 h (94%) in most of patients, and < 6 hours (37.5%) in 6 patients. Regarding the complementary tests, ultrasound was normal in 12 (75%) and PCT was negative in 10 of these patients (62%). No association with any of the studied factors was found in the assessment of permanent renal damage. Specifically, OR was 1.0 for PCT (95% CI 0.9-1.1, P=.6), and 0.4 in patients younger than one (95% CI 0.1-1.4; P=.1). DISCUSSION The aim of this study was to assess the usefulness of PCT and other analytical (leukocytes, CRP, etc.) and clinical (age, hours of fever, etc.) parameters as indicators of acute and permanent renal damage in children after their first episode of febrile UTI. Our study includes a considerably sized group with respect to those studies published to date of patients diagnosed with first episode of febrile UTI with high theoretical possibility of acute scinitgraphic affectation due to analytical alterations presented on admission (leukocyte count above the upper value of the normal range according to age and/or CRP levels >30mg/l). In addition, DMSA, the gold standard for renal damage diagnosis, both acute and permanent, according to general recommendations at the time of the test, was performed on all patients. The percentage of acute-phase pathological DMSA was 64.8% in our series, very similar to the rest of the published studies16,17,19,24,26,28. Contrary to what was expected 6, in the cases of infection by bacterium other than E. coli, the percentage of acute-phase pathological DMSA was lower (53%), with 3 developing scarring (19%). The clinical and analytical characteristics of this group of patients were analysed, without finding any risk or confusion factor justifying this result. PCT has demonstrated its validity in the early diagnosis of invasive bacterial infections, surpassing CRP14,15. As regards UTI, PCT was the most studied marker and currently offers the best results. Since Benador published his study in 1998, numerous studies have tried to find a cut-off point for PCT with could be related to both risk of acute parechymatous damage and permanent scarring16. The majority of publications, except for two, have shown the usefulness of PCT, although with very inconsistent S and Sp values 17,18,19-27. Although sample sizes are often small, we highlight Leroy’s 2013 meta-analysis which assesses 18 independent studies, thus obtaining a total of Table 2. Comparison between normal and pathological acute-phase dimercaptosuccinic acid Normal DMSA (n = 75)a Pathological DMSA (n = 142)a P Age 5 months [7 days – 8 years] 7 months [3 months – 14.9 years] 0.005 Sex 40 % male 40 % male 1 24.3 % 7.7 % 0.3 17,700 [8,100-41,600] 18,100 [3,900-35,400] 0.4 79.24 (59.24) 112.8 (87.12) 0.01 1.44 (1.85) 4.8 (8.62) 0.0001 < 6 hours of fever Mean leukocytes (/mm3) [range] Mean CRP (mg/l) (SD) Mean PCTb (ng/ml) (SD) SD: standard deviation; DMSA: dimercaptosuccinic acid; CRP: C-reactive protein; PCT: procalcitonin. a Late DMSA was only performed in 2 cases; b Only PCT values were considered quantitative. 454 Nefrologia 2014;34(4):451-7 originals 1.0 1.0 0.8 0.8 0.6 0.6 Sensitivity Sensitivity Elena Lucas-Sáez et al. Procalcitonin, predictor of kidney damage 0.4 0.4 0.2 0.2 0.0 0.00.20.40.6 0.81.0 0.0 0.00.20.40.60.81.0 1-Specificity 1-Specificity Figure 2. ROC curve for procalcitonin in acute kidney damage. Figure 3. ROC curve for procalcitonin in renal scarring. 1,011 patients26. In this instance, PCT shows good results for acute renal damage and low Sp for renal scarring. calculating the area below the curve, optimal PCT values of 0.85 and 1.17ng/ml were found as cut-off points, which are similar to those proposed in other studies (1ng/ml in the studies by Sheu and by Bressan, and 0.85ng/ml proposed by Kotoula)24,23. However, our S, Sp, PPV and NPV values are much lower than those discovered in these studies. Our study, as well as providing a considerably larger sample size than the majority of previous publications, includes a multivariate analysis to independently determine the association between the variables of interest and renal involvement. As regards acute renal damage, we found significantly higher PCT averages in patients with pathological DMSA. After With respect to renal scarring, the increase of PCT values did not achieve statistical significance. The area below the ROC curve was similar to that for acute damage, and for the same PCT values as cut-off points, we found acceptable values of Table 3. Diagnostic validity of procalcitonin with respect to Tc 99m dimercaptosuccinic acid in acute damage PCT S Sp PPV NPV >0.85 ng/ml 74 46 72 48 >1.17 ng/ml 67 61 77 49 Sp: specificity; PCT: procalcitonin; S: sensitivity; NPV: negative predictive value; PPV: positive predictive value. Table 4. Diagnostic validiy of procalcitonin with respect to Tc 99m dimercaptosuccinic acid in renal scarring PCT S Sp PPV NPV >0.85 ng/ml 80 30 28 81 >1.17 ng/ml 80 37 31 84 Sp: specificity; PCT: procalcitonin; S: sensitivity; NPV: negative predictive value; PPV: positive predictive value. Nefrologia 2014;34(4):451-7 455 originals Elena Lucas-Sáez et al. Procalcitonin, predictor of kidney damage S, but very low E and PPV values. Our data, with respect to the usefulness of PCT for diagnosing permanent renal damage, did not allow room for recommendations made by other authors16-27. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. In reference to the other markers studied, only CRP achieved certain usefulness in the diagnosis of acute damage, similar to the study by Kotoula23. REFERENCES The results of the multivariate analysis demonstrate that only two factors were relevant: PCT and <6 hours of fever. Each unit that increases PCT represents a 20% greater risk of acute parenchymatous damage. In contrast, <6 hour fever duration gave 60% protection. Contrary to that expected, an age of <1 proved to be a protecting factor for acute and chronic parenchymatous affectation; however, statistical significance was not achieved. The results of our study demonstrate certain usefulness of PCT for predicting acute renal damage in patients undergoing their first episode of febrile UTI. Although we cannot establish PCT cut-off values in those patients with low PCT levels, ultrasound normality and good initial evolution, the performance of acute-phase DMSA could be prevented. However, data obtained until now does not allow the use of PCT as a predictor of renal scarring in these patients. Our study has certain limitations. Firstly, it is a retrospective study. Second, the urine collection method in a significant percentage of cases was via perineal bag and not using a sterile technique, as recommended in the latest clinical practice guidelines. However, having two urine cultures, with growth of the same bacterium and in significant number, as well as urinalysis with inflammatory signs, minimises the possibility of false positives. Finally, of the 142 patients with acute-phase DMSA, only 99 late DMSA were performed during the study, since in some cases sufficient time had not elapsed for it to be carried out (5 patients) or the initial scintigraphic affectation was mild and clinical evolution satisfactory (16 patients). Some patients were also lost to follow-up (22 cases, 10% of the sample). Due to this small sample of patients with renal scarring, we are not able to obtain concluding statistical data. CONCLUSIONS PCT increase and <6 hour fever duration were the only parameters which were significantly associated with acute parenchymatous damage. No statistically significant association was observed between PCT and renal scarring. 456 1. Hoberman A, Chao HP, Keller DM, Hickey R, Davis HW, Ellis D. Prevalence of urinary tract infection in febrile infants. J Pediatr 1993;123(1):17-23. 2. Marild S, Jodal U. Incidence rate of first-time symptomatic urinary tract infection in children under 6 years of age. Acta Paediatr 1998;87(5):549-52. 3. Elder JS. Urinary tract infections. In: Kliegman RM, Stanton B, Geme JS, Schor N, Behrman RE. Nelson Textbook of Pediatrics. 19th Edition. Philadelphia: Saunders Eselvier; 2011. pp. 1900-5. 4. Subcommittee on Urinary Tract Infection, Steering Committee on Quality Improvement and Management, Roberts KB. Urinary tract infection: clinical practice guideline for the diagnosis and management of initial UTIs in febrile infants and children aged 2 to 24 months. Pediatrics 2011;128(3):595-610. 5. Practice parameter: the diagnosis, treatment, and evaluation of the initial urinary tract infection in febrile infants and young children. American Academy of Pediatrics. Committee on Quality Improvement. Subcommittee on Urinary Tract Infection. Pediatrics 1999;103:843-52. 6. Grupo de trabajo de la Guía de Práctica Clínica sobre Infección del Tracto Urinario en la Población Pediátrica. Guía de Práctica Clínica sobre Infección del tracto Urinario en la Población Pediátrica. Plan de Calidad para el Sistema Nacional de Salud del Ministerio de Sanidad, Política Social e Igualdad. Instituto Aragonés de Ciencias de la Salud; 2011. Guías de Práctica Clínica en el SNS: I CS Nº 2009/01. 7. National Collaborating Centre for Women´s and Children´s Health, Commissioned by the National Institute for Health and Clinical Excellence. Urinary tract infection in children: diagnosis, treatment and long-term management. London: RCOG Press; 2007. 8. Saadeh SA, Mattoo TK. Managing urinary tract infections. Pediatr Nephrol 2011;26(11):1967-76. 9. Rushton HG. The evaluation of acute pyelonephritis and renal sparring with technetium 99m-dimercaptsuccinic acid renal scintigraphy: evolving Concepts and future directions. Pediatr Nephrol 1997;11:108-20. 10. Biggi A, Dardanelli L, Pomero G, Cussino P, Noello C, Sernia O, et al. Acute renal cortical scintigraphy in children with a first urinary tract infection. Pediatr Nephrol 2011;16:733-8. 11. González Rodríguez JD, Canalejo D, Martin Govantes JJ, García de Guadiana L, Rex C, González Morales M, et al. Proteinuria in urinary infection and acute pyelonephritis in paediatric patients: can it replace scintigraphic studies in diagnostic localization? Nefrologia 2009;29(2):163-9. 12. Spasojevic-Dimitrijeva B, Zivkovic M, Stankovic’ A, Stojkovic’ L, Kostic’ M. The IL6-174 G/C polymorfism and renal scarring in children with first acute pyelonephritis. Pediatr Nephrol 2010;25(10):2099-106. 13. Rodríguez LM, Robles B, Marugán JM, Suárez A, Santos F. Urinary Nefrologia 2014;34(4):451-7 Elena Lucas-Sáez et al. Procalcitonin, predictor of kidney damage IL6 is useful in distinguishing between upper and low urinary tract infection. Pediatr Nephrol 2008;23(3):429-33. 14. Marin Reina P, Ruiz Alcántara I, Vidal Micó S, López-Prats Lucea JL, Modesto I Alapont V. Exactitud del test de PCT en el diagnóstico de bacteriemia oculta en pediatría. An Pediatr (Barc) 2010;72(6):40312. 15. Manzano S, Bailey Benoit, Gervaix A, Cousineau J, Delvin E, Girodias JB. Markers of bacterial infection in children with fever without source. Arch Dis Child 2011;96:440-6. 16. Benador N, Siegrist CN, Gendrel D, Greder C, Benador D, Assicot M, et al. Procalcitonin is a marker of severity of renal lesions in pyelonephritis. Pediatrics 1998;102:1422-5. 17. Güven AG, Hazdal HZ, Koyun M, Aydn F, Güngör F, Akman S, et al. Accurate diagnosis of acute pyelonephritis: how helpful is procalcitonin? Nucl Med Commun 2006;27:715-21. 18. Tuerlinckx D, Vander Borght T, Glupczynski Y, Galanti L, Roelants V, Krug B, et al. Is procalcitonin a good marker of renal lesion in febrile urinary tract infection? Eur J Pediatr 2005;164:651-2. 19 Sheu JN, Chang HM, Chen SM, Hung TW, Lue KH. The role of procalcitonin for acute pyelonephrytis and subsequent renal scarring in infants and young children. J Urol 2011;186:2002-8. 20. Prat C, Domínguez J, Rodrigo C, Giménez M, Azuara M, Jiménez O, et al. Elevated serum procalcitonin values correlate with renal sparring in children with urinary tract infection. Pediatr Infect Dis J 2003;22:438-42. originals 21. Pecile P, Miorin E, Romanello C, Falleti E, Valent F, Giacomuzzi F, et al. Procalcitonin: a marker of severity of acute pyelonephritis among children. Pediatrics 2004;114:e249-54. 22. Gürgoze MK, Akarku S, Yimaz E, Gödekmerdan A, Akça Z, Ciftçi I, et al. Proinflammatory cytokines and procalcitonin in chilren with acute pyelonephritis. Pediatr Nephrol 2005;20:1445-8. 23. Kotoula A, Gardiki S, Tsalkidis A, Mantadakis E, Zissimopoulos A, Kambouri K, et al. Procalcitonin for the early prediction of renal parenchymal involvement in children with UTI: preliminary results. Int Urol Nephrol 2009;41:393-9. 24. Bressan S, Andreola B, Zucchetta P, Montini G, Burei M, Perilongo G, et al. Procalcitonin as a predictor of renal scarring in infants and young children. Pediatr Nephrol 2009;24:1199-204. 25. Nikfarr R, Khotaee G, Ataee N, Shams S. Usefulness of procalcitonin rapid test for the diagnosis of acute pyelonephritis in children in the emergency department. Pediatr Int 2010;52:196-8. 26. Leroy A, Fernández-López A, Nikfar R, Romanello C, Bouissou F, Gervaix A, et al. Association of procalcitonin with pyelonephritis and renal scars in pediatric UTI. Pediatrics 2013;131:870-9. 27. Chen SM, Chang HM, Hung TW, Chao YH, Tsai JD, Lue KH, et al. Diagnostic performance of procalcitonin for hospitalised children with acute pyelonephritis presenting to the paediatric emergency department. Emerg Med J 2013;30:406-10. 28. Montini G, Tullus K, Hewitt I. Febrile urinary tract infections in children. N Engl J Med 2011;365:239-50. Sent to review : 30 Jan. 2014 | Accepted: 7 Apr. 2014 Nefrologia 2014;34(4):451-7 457 originals http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society Cost analysis and sociocultural profile of kidney patients. Impact of the treatment method Víctor Lorenzo-Sellares1, M. Inmaculada Pedrosa1, Balbina Santana-Expósito2, Zoraida García-González3, Mónica Barroso-Montesinos4 1 Servicio de Nefrología. Hospital Universitario de Canarias. La Laguna, Santa Cruz de Tenerife (Spain); 2 Servicio de Evaluación de la Calidad. Servicio Canario de Salud. Santa Cruz de Tenerife (Spain); 3 Servicio de Nefrología. Hospital Tamaragua. Puerto de la Cruz, Santa Cruz de Tenerife (Spain); 4 Unidad de Apoyo a la Investigación. Hospital Universitario de Canarias. La Laguna, Santa Cruz de Tenerife (Spain) Nefrologia 2014;34(4):458-68 doi:10.3265/Nefrologia.pre2014.Apr.12501 ABSTRACT Background: The cost analysis of chronic kidney disease based on individual data for treatment methods and components has not been published in Spain. Objectives: a) To study the health costs of a year of treatment with haemodialysis (HD), deceased donor renal transplantation (RTx), renal-pancreas transplantation (RPTx), and S4 and S5 advanced chronic kidney disease (ACKD) b) Assess the potential relationship between sociocultural diversity, costs and treatment method. Methods: Observational study of: 1) 81 patients with ACKD (53 S4 and 28 S5) 2) 162 with more than 3 months on HD and 3) 173 with a Tx for more than 6 months (140 RTx and 33 RPTx). The costs were assessed in five categories: 1) HD sessions, 2) drug intake, 3) hospitalisation, 4) outpatient care and 5) transportation. We carried out a survey with sociodemographic parameters. Results: The financial impact of HD was €47,714±18,360 (mean±SD), that of Tx €13,988±9970, and that of ACKD €9654±9412. The cost of HD was the highest in all financial items. The costs were similar between RTx and RPTx. In ACKD, the greater the renal deterioration, the greater the cost is (S4 €7846±8901 versus S5 € 13,300±9820, P<.01). Tx patients had the best sociocultural status, while HD patients had the worst profile. We did not find differences in costs between the three sociocultural groups. Conclusions: HD has the greatest financial impact in all items, five times higher than the ACKD patient cost and three times than the Tx patient cost. Optimising early prevention and Tx, if appropriate, must be priority strategies. This analysis invites us to think about whether sociocultural status can have an influence on opportunities for Tx. Keywords: Costs-of-illness. Economic evaluation. Advanced chronic kidney disease. Hemodialysis. Kidney transplant. Diagnosis-related groups. Sociocultural level. Análisis de costes y perfil sociocultural del enfermo renal. Impacto de la modalidad de tratamiento RESUMEN Antecedentes: El análisis del coste de la enfermedad renal crónica basado en datos individuales, por componentes y modalidades terapéuticas no ha sido publicado en España. Objetivos: a) Estudiar los costes sanitarios de un año de tratamiento con hemodiálisis (HD), trasplante renal (TxR) de cadáver y reno-páncreas (TxRP), y de la enfermedad renal crónica avanzada (ERCA) E4 y E5. b) Evaluar la eventual relación entre disparidad sociocultural, costes y modalidad de tratamiento. Métodos: Estudio observacional de: 1) 81 pacientes con ERCA (53 E4 y 28 E5); 2) 162 con más de 3 meses en HD y 3) 173 con más de 6 meses Tx (140 TxR y 33 TxRP). Los costes se evaluaron en cinco categorías: 1) sesiones de HD, 2) consumo farmacéutico, 3) hospitalizaciones, 4) atención ambulatoria y 5) transporte. Se realizó una encuesta de parámetros sociodemográficos. Resultados: El impacto económico de la HD fue de 47 714 ± 18 360 € (media ± DS), el del Tx de 13 988 ± 9970 €, y el de la ERCA 9654 ± 9412 €. El coste de la HD fue el más elevado en todas las partidas económicas. Los costes fueron similares entre TxR y TxRP. En ERCA, a mayor deterioro renal, mayor coste (E4 7846 ± 8901 frente a E5 13.300 ± 9.820, p < 0,01). Los pacientes Tx tenían mejor estatus sociocultural, mientras que los de HD presentaban el peor perfil. No encontramos diferencias en los costes entre los tres grupos socioculturales. Conclusiones: La HD conlleva el mayor impacto económico en todas las partidas, incrementando cinco veces el coste del paciente ERCA y tres veces el del Tx. Optimizar la prevención precoz y el Tx, llegado el caso, deben ser estrategias prioritarias. Este análisis invita a reflexionar acerca de si el estatus sociocultural puede influir en ventajas de oportunidades para el Tx. Palabras clave: Coste de la enfermedad. Evaluación económica. Enfermedad renal crónica avanzada. Hemodiálisis. Trasplante renal. Grupos relacionados con el diagnóstico. Nivel sociocultural. Impact of the 5008 monitor software update on total Correspondence: Víctor Lorenzo Sellares Servicio de Nefrología. Hospital Universitario de Canarias. Llombet, 27. 38296 La Laguna. (Spain). Santa Cruz de Tenerife. [email protected] 458 INTRODUCTION The population with chronic kidney disease (CKD) who require renal replacement therapy (RRT) is constantly growing1,2. This is fundamentally due to an increase in the elderly and diabetic Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients population3. RRT is a major component of healthcare spending, given that, although the volume of patients is lower than 0.1% of the population, the healthcare budget is 2.5% for this population4. According to data of the EPIRCE (Chronic Renal Failure Epidemiology in Spain) study, the Spanish population that suffers advanced CKD (ACKD) stages (S) 4 and 5 is approximately 0.3% (around 130,000 individuals)2, to which we must add the 50,000 patients who are on RRT: 51% kidney transplant patients (RTx), 44% on haemodialysis and 5% on peritoneal dialysis (PD)5. In healthcare economics, cost plays an important role, especially in chronic diseases, such as CKD and diabetes, given the ageing population and the progressive number of exposed patients. Therefore, priority must be given to addressing the high social and financial costs of treatment 6 . However, the information available on a national level is poor and is fundamentally focussed on HD 7,8 . In any case, it is very difficult to compare studies, since the cost estimation varies depending on whether or not different direct and indirect components are included. Likewise, there is usually wide variability depending on the public or subsidised status of hospitals and the different use of resources. It is even more complicated to compare costs between countries with different healthcare models, both in terms of financing and in the provision of services 9-11. Despite thesse difficulties, knowledge and analysis of costs is both important and necessary6. With this information we can achieve an overview of the effect of illness on the use of resources. Furthermore, knowledge of the cost distribution between the different components would allow us to identify areas of inefficiency, in order to allocate resources better12. Many studies have shown that RTx and PD are considerably cost-effective when compared with HD13-16. In our setting, we have heterogeneous information about the cost of HD and PD; however, the cost of ACKD patient treatment has not been analysed in our country and we do not have detailed data on patients who have received transplants. originals with HD, RTx and RPTx. The study population comprised the Northern Health Area of the province of Santa Cruz de Tenerife, and the reference hospital was the Hospital Universitario de Canarias (HUC). This region has a population of approximately 400,000 inhabitants. Study subjects We evaluated three populations, who were initially surveyed between November 2009 and December 2009, and we finished collecting data in December 2011. Patients who completed at least six months of follow-up were included in the final analysis and the cost allocation was extrapolated to one year. Those who were not followed up for six months were excluded due to the study period being considered to be too short. Likewise, exclusion criteria included the following: 1) patients whose circumstances or illness may have interfered with the study (for example, drug users and individuals with cognitive deficiencies or disorders); 2) when informed consent could not be obtained or was not given; 3) a lack of adherence to medical recommendations or a lack of collaboration from the patient or their responsible family member. The final study included: 1. In the HUC’s ACKD clinic follow-up: 81 patients, 53 S4 and 28 S5. 2. HD patients who had spent at least three months on this form of RRT: 85 HUC patients and 77 patients from the Hospital Tamaragua. These are two subsidised hospitals with a dialysis cost established in an agreement. 3. Patients followed up in the HUC’s RTx clinic who had received their transplant at least six months before: 140 patients with RTx and 33 with RPTx. Our objective was to study the financial impact of treatment with HD, deceased donor RTx and renal-pancreas transplantation (RPTx), and the management of S4 and S5 ACKD (not yet on dialysis). A secondary objective was to investigate the demographic and sociocultural profile of this population and its possible association with cost and method of treatment. Healthcare costs We defined “cost” as the consumption of goods and services valued in monetary terms, to achieve a certain objective or obtain a certain product. In order to estimate the cost, we used the prevalence cost method, i.e., the direct healthcare costs attributable to the illness in the study year17. These were organised into five main categories: 1) HD sessions, 2) medication use, 3) hospitalisation, 4) outpatient care in clinics, emergency departments and complementary tests and examinations, and 5) transportation use. MATERIAL AND METHOD Design Observational study of direct healthcare costs during one year of treatment for patients affected by ACKD and on RRT Haemodialysis sessions For the specific cost of HD sessions, there are different models depending on the country. The model applied in our setting is the one most commonly used in Europe, i.e., a fixed amount per dialysis session, which is adjusted to a Nefrologia 2014;34(4):458-68 459 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients originals protocol of action. In the Official Canary Gazette18, for this method, there is just one activity that is charged: the HD session, with certain variability depending on the hospital and the services. The cost of HD in accordance with the agreement established included the cost of consumables, with a supplement for special membranes accepted for 10% of patients, repayment of non-disposable material, staff and medication administered during the HD session, with the exception of erythropoiesis-stimulating agents (ESA). As such, we applied €146 for the HUC outpatient unit and €158 for the Hospital Tamaragua. There was no difference in reimbursement depending on the number of hours per session or the method of treatment. Regular examinations that were carried out on these patients were included in the dialysis reimbursement, and as such, they were not included under a different heading. The normal HD regimen in all hospitals was four hours, three times a week. Medication expenses Information on the consumption of medications and diagnosis material for self-monitoring was taken from clinical databases and from surveys carried out on patients and/or their family members. The cost was obtained by calculating the price of each unit in euros and multiplying it by the dose. The costs were obtained from different sources, such as the Pharmaceutical College Medications Database. This expense was expressed in euros/patient/day or year, as appropriate, in the presentation of results. In this study, we did not consider the discounts offered by many pharmaceutical companies in a different format. Hospitalisation The volume of hospital admissions was obtained from the two hospitals where the patients were admitted. We recorded the total number of admissions over the study period and applied the attributable fractions of morbidity for each diagnosis code of the International Classification of Diseases (ICD-9-CM) and their subsequent processing by diagnosis-related group (DRG). DRG, as a patient risk-adjusted system, incorporate a cost estimator, which is a measure of the mean complexity of the patients, and the “relative weight”, or level of resource consumption attributable to each patient type or group19. The mean cost of each DRG was obtained from the Ministry of Health and Consumption’s Health Information System. Outpatient care Outpatient care includes hospital or primary care centre consultations, vascular access for HD carried out in an outpatient setting, and complementary and imaging studies. 460 Information on the use of these healthcare resources was obtained from three sources: a review of clinical records, a review of digital hospital records and a review of the survey carried out on patients and/or their family members. To allocate the cost of consultations and complementary studies, we used the HUC invoicing tables, the reimbursement tables established by the Canary Health System (SCS) and the allocations for procedures published in the Official Canary Gazette18. Transportation We must add the cost for use of transportation to hospitals to that of the HD sessions. This expense was obtained from the reimbursement tables established by the SCS for the use of private cars, taxis, health buses, non-emergency ambulances and emergency ambulances. We also recorded the possible use of transport for travel to clinics or for imaging tests. Sociodemographic variables We carried out a generic survey on patients and/or a relative, according to the individual circumstances. The following data were collected: age, sex, underlying disease, educational level, employment status and work activity, autonomy, family support, living environment (urban, rural). Subsequently and with the aim of simplifying the analysis, we summarised and grouped the scores in accordance with the level of studies and work activity. In this manner, patients were classified into three groups of sociocultural status: 2 points: lower, 3 points: lowermiddle, >3 points: middle-upper. Data analysis The results of this study are fundamentally descriptive, and as such, we have exclusively used basic statistics tests. Given that the cost values were extreme in some patients, there was an asymmetric distribution towards high values. This is highlighted because the mean was higher than the median, particularly for the expenses of hospitalisation and consultation, not used in many cases. For these types of data with many extreme values, the median must be considered to be a stronger comparison parameter; however, the arithmetic mean is considered to be more informative of the total cost for decision-making about health policies 20-24 . Finally, we presented the results in both formats, mean ± standard deviation (SD) and median (interquartile range [IR]). The statistical analyses were carried out with the SPSS 17.0 software for Windows (SPSS Inc, Chicago, ILL). Nefrologia 2014;34(4):458-68 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients originals by transplantation, while this financial item in ACKD is less than half the cost of that of the other methods (Table 1). RESULTS When we analysed the annual cost by treatment method, we found that the greatest financial impact was made by HD, which was more than three times the cost of treatment for transplant patients and almost five times that of ACKD patients. The explanation seems simple: the higher cost is represented by the HD technique, which is not used in transplant patients or ACKD patients. In any case, the cost in HD patients is higher in all financial items. Table 1 displays the mean (SD) and median (IR) of the detailed costs by financial item and treatment method. Hospitalisation costs The financial impact of hospitalisation is less that it may have seemed a priori. This is due to the considerable proportion of patients not being admitted, which thus reduces the mean cost. Again, the highest financial impact was caused by HD, which on average was double the cost of that of patients with ACKD or transplant patients (Table 1). The proportion of patients who were admitted at least once was also maintained according to methods: 68% of HD patients were admitted one or more times, while this was only true of 41% and 40% of patients with ACKD and transplant patients, respectively. If we only consider the costs of those who were hospitalised at least once, the financial impact per treatment method is considerably diminished: ACKD €13,339±€8,539, HD €17,655±€16,726 and transplantation €12,193±€10,604. Cost of haemodialysis sessions With the model adopted, the cost of HD sessions was practically identical for all patients according to the subsidised hospital, independently of comorbidity, sociocultural status or location of residence. Differences were only observed in the small proportion of patients who received more than three sessions per week. This cost, as we have mentioned before, is combined in a reimbursement stipulated by the SCS. The average patient/year cost was almost €25,000 (Table 1). Outpatient care Costs for outpatient care are not very high and not as disparate between methods, representing an average of €1,000-€1,800 per year per patient. Medication costs The medication costs by treatment method also showed the highest expense to be in HD, followed very closely Table 1. Detailed costs by financial item and treatment method HD sessions Medication Hospitalisation Transportation Outpatient Care Totals Totals ACKD HD Tx Mean (SD) 24,572 (3,426) 0 24,572 (3,426) 0 Median (IR) 24,726 (22,922-26,228) 0 24,726 (22,922-26,228) 0 Mean (SD) 5,269 (3,672) 2,502 (1,883) 6,231 (4,438) 5,580 (2,775) Median (IR) 4,616 (2,888-6,691) 2,073 (1,288-3,195) 5,600 (3,433-7,590) 4,925 (3,937-6,671) Mean (SD) 7,748 (12,602) 5,434 (8,524) 11,987 (16,055) 4 863 (8,961) Median (IR) 1,831 (0-10,428) 0 (0-8,379) 5,258 (0.000-15,833) 0 (0-5,575) Mean (SD) 1,311 (2,800) 91 (145) 3,076 (3,856) 228 (411) Median (IR) 80 (36-614) 46 (32-80) 646 (20-5197) 76 (51-173) Mean (SD) 1,554 (1,747) 1,030 (1,087) 1,809 (2,353) 1,562 (1,202) Median (IR) 1,003 (503-1,945) 654 (356-1237) 995 (396-2,116) 1,228 (723-2,013) Mean (SD) 26,278 (22,030) 9,654 (9,412) 47,714 (18,360) 13,988 (9,970) Median (IR) 19,026 (8,459-38,612) 5,623 (2,946-14,207) 41,120 (34,102-56,505) 10,516 (7,311-16,962) Values in euros, expressed as the mean and standard deviation, and the median and interquartile range. SD: standard deviation, ACKD: advanced chronic kidney disease, HD: haemodialysis, IR: interquartile range, Tx: renal transplantation. Nefrologia 2014;34(4):458-68 461 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients originals Transportation The financial impact of transportation is minimal in ACKD and transplant patients, while it is €3,000 in HD, since these patients need to travel three times a week. This amount represents 6% of the total cost of treatment and 12.5% of the cost of HD. Costs by renal transplantation method Table 2 shows that the overall and detailed costs of a year of treatment, from six months after transplantation onwards, were not significantly different between RTx and RPTx. Costs by advanced chronic kidney disease stage In this section, we observed major differences in terms of costs and the degree of renal damage (Table 3). Expenses for S5 patients were significantly higher than those for S4 patients, particularly in terms of medication and hospitalisation. That said, they continue to be around 30% lower than those observed in HD, and similar to those attributed to transplant patients. Table 2. Detailed costs by financial item and type of transplantation Expenses RTx RPTx Medication 5,495±2,882 5,940±2,269 Biochemical study 766±789 1,353±1,088 Outpatient Care 1,621±1,200 1,314±1,193 Hospitalisation 5,130±9,337 3,731±7,164 14,011±10,375 13,891±8,166 Totals RTx: renal transplantation, RPTx: renal-pancreas transplantation. Association between cost and sociocultural parameters Table 4 displays sociodemographic data by treatment method. It shows that the degree of sociocultural deprivation is considerable; this is defined as the group of circumstances that are an obstacle to normal access to healthcare for people who live in cultural and material poverty. As such, we observed that transplant patients had a better sociocultural position, while those on HD had a worse profile. Around 85% of HD patients had not graduated from school and had an unskilled job. Likewise, this analysis also showed that autonomy and family support are parallel to sociocultural level and, thus, they were higher in the transplant population. In any case, in the transplant population, 65% of patients had not graduated from school (Table 5). The ACKD population had an intermediate profile. Overall, the lower sociocultural profile, as can be imagined, was more apparent in rural areas or towns. When we analysed the detailed costs in the three sociocultural groups, no relevant differences were found, even when they were classified by treatment method. The transportation expense was lower in patients of a higher sociocultural level, which shows that they more frequently use their own means. DISCUSSION In this study, for the first time, we analysed the costs of treatment of patients with S4 and S5 ACKD and RTx and RPTx patients for a specific region, using individual data and not overall budgets. As authors, we are aware that the allocations to the different financial items are difficult to extrapolate given variations in cost in the different regions and the sudden budgetary changes that occur. However, the proportional analysis of each item and each treatment method may be useful. The greatest obstacle in carrying out the study was the impossibility of including PD, with the latter being a costeffective alternative for the sustainability of RRT21-23. At the Table 3. Detailed costs by financial item and advanced chronic kidney disease stage Expenses S4 S5 P Medication 2,090±1,285 3,264±2,530 <0.03 330±234 384±343 Outpatient Care Biochemical study 1,091±1,202 928±871 Hospitalisation 4,004±7,702 8,348±9,649 <0.03 Totals 7,846±8,901 13,300±9,820 <0.01 S4: stage 4, S5: stage 5, 462 Nefrologia 2014;34(4):458-68 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients originals Table 4. Sociodemographic data by treatment method ERCA HD Tx P Number of patients 81 162 173 Age (years) 69 ± 13 68 ± 12 51 ± 13 Sex (M, %) 70 61 69 Diabetes (%) 43 46 23 79.0 84.6 64.7 0.001 2. Bachiller elemental 6.2 9.3 6.4 3. > Bachiller superior 14.8 6.2 28.9 Retired due to age 55.2 56.3 12.5 0.001 Retired due to illness 25.4 41.5 53.3 Active 19.4 2.2 34.2 1. Unskilled 62.5 85.0 44.8 0.001 2. Vocational professional 28.8 10.0 38.7 Level of studies Employment status Work Activity 1. < SchGr 3. Graduate 8.8 5.0 16.6 Self-sufficient 81.5 69.8 90.8 0.001 Partial assistance 16.0 19.1 8.7 Full assistance 2.5 11.1 0.6 Family support Low 16.0 30.2 4.6 0.001 Medium 40.7 47.5 17.3 High 43.2 22.2 78.8 Living environment Rural 13.6 13.0 2.9 0.001 Town 55.6 38.9 52.0 City 30.9 48.1 45.1 Autonomy ACKD: advanced chronic kidney disease, SchGr: school graduate, HD: haemodialysis, Tx: transplantation. start of the study, the number of patients in our hospital was low and although the incident rate grew, we quickly lost the technique due to transplantation or due to the temporary or definitive change to HD. Since we were not able to increase the number of patients followed-up in time, we ceased to analyse this treatment method. In general, the European series estimate that the cost of PD is between the wide range of 30%70% less than that of HD13,22,24, which means that it is close to RTx costs. However, a recent article by Lamas Barreiro25 questions the allocation of costs, reopening the debate on the financial advantages of PD. In fact, the incorporation of biocompatible supplements, polyglucose or automation raises its price even above that of HD4. Cost of renal replacement therapy by treatment methods Table 1 highlights that HD patients cost was almost five times greater than that of ACKD and more than three times greater than that of transplantation. A more detailed analysis by financial items showed us that HD is mainly more expensive due to the cost of HD sessions, but it is also more expensive Nefrologia 2014;34(4):458-68 in all financial items, particularly that of hospitalisation, in which it is double the costs of the other two methods. However, the hospitalisation cost of transplant patients is very similar to that of ACKD patients. Classically, RTx has been described as the most efficient treatment option with the lowest cost from the second year onwards. However, our data show that the financial advantages of transplantation are detected at least after six months. Haller et al.13 recently published a cost analysis in Austria that was similar to ours. Despite being countries with different structures and socioeconomic circumstances, the costs during the second year of treatment were slightly lower than in our study for HD (mean±SD: 40,000±10,900 vs. 47,700±18,400) and somewhat higher for RTx (17,200±13,000 vs. 14,000±10,000). In the transplantation section, the costs between the two methods (RTx and RPTx) were not majorly d i ff e r e n t , s u g g e s t i n g t h a t R P T x d o e s n o t e n t a i l a higher cost from the sixth month onwards. Unfortunately, there are no other studies that allow us to make comparisons. 463 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients originals Table 5. Renal replacement therapy method and sociocultural status ACKD HD Tx Lower n 47 124 67 % 58.0% 77.5% 41.1% n 18 21 34 % 22.2% 13.1% 20.9% n 16 15 62 % 19.8% 9.4% 38.0% Lower-Middle Middle-Upper Matrix table showing significant differences between methods and status (c2 p<.0001). ACKD: advanced chronic kidney disease, HD: haemodialysis, Tx: transplantation. With regard to ACKD patients in Spain, no data have been published, and as such, ours may be a new precedent for epidemiological estimation of this cost. According to the results of the Spanish EPIRCE study 2, S4 and S5 CKD prevalence is 0.27% (118,800 individuals) and 0.03% (13,200 individuals), respectively. Given these data and the annual cost taken from our study, we can infer that, in the event that all of these patients were detected and monitored in an ACKD clinic, the annual financial amount for managing this population in Spain would be no less than 1108 million euros. Recently in the United States, Honeycutt et al.26 carried out a macroepidemiological ACKD cost analysis. Annual costs were $1,700 for patients in S2, $3,500 for S3 patients and $12,700 (around €10,000) for S4 patients, which demonstrates the major increase in cost as the disease worsens. In our series we also confirmed that, the greater the renal damage, the greater the expense. The cost increased 59% between S4 and S5 (from €7,846 to €13,300), and the greatest increase was observed in medication and hospitalisation costs. It is notable that, in spite of the enormous disparity between health systems, the S4 cost in our series was only 20% higher than that published by Honeycutt et al.26. The costs of the lower financial impact sections (transportation and outpatient care) were also greater for HD patients. The only clear difference between transplant and ACKD patients was in the medication section, where the transplant patient costs were double the ACKD patient costs. Treatment with haemodialysis Allocating expenses attributable to HD is a complicated issue. Most countries with structured public health services pay HD costs, with a standard price per session being assigned and minimum quality criteria being imposed. In general, Spanish health services have adopted this model, including the SCS. However, even within this model there is variability in the options, depending on the hospital and the type of subsidising4. 464 Some Spanish studies have gone further in addressing the cost of HD, demonstrating that, although they were carried out more than a decade ago, the costs did not differ significantly from current costs27,28. In 2008, Parra Moncasi et al.8 carried out a detailed study on the cost of HD in public and subsidised hospitals. The subsidised hospital cost was €32,872-€35,294, and it was 23% higher in public centres. These costs are approximately 33% higher than those reimbursed by the SCS, but they include expenses that we allocate to other areas (dialysis and outpatient medication, imaging diagnostics and transportation), which represent 40% of the cost in the study by Parra Moncasi8. Therefore, we must assume that the reimbursement by the SCS for HD is quite close to the real costs obtained by these authors8. Outside our country, a Canadian study10 published in 2002 reported an overall annual HD cost in hospitals of €43,528 (95% confidence interval [CI] €40,528-€46,600) (dollar-euro conversion: €0.85 = 1 American dollar). The cost analysis was carried out with categories that were similar to our own, although the price of the doctor was included under a different heading. Specifically, the cost of HD was €22,688. In spite of the innumerable differences between healthcare models and structures, the specific cost of HD and its proportion of the overall cost of treatment were similar to our study. Moreover, other European studies, methodologically different, reported an HD treatment cost that covered a wide range between €20,000-€80,000/patient/year29,30. Our costs are somewhere near the middle of this range, but unfortunately a more in-depth comparison is impossible with the information available to us. More recently, Icks et al.31 published a study on the overall cost of HD in 2006 in a region of Germany, analysing similar cost components to ours. The overall mean cost was €54,777/patient/year, that is, 15% higher than in our study, fundamentally due to the HD procedure (€30,029/ patient/year). Hospital HD may considerably increase the cost, with around €200 being allocated per session32, which results in an even greater increase in the HD patient cost. Nefrologia 2014;34(4):458-68 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients Medication expenses The medication expenses item was the third largest by percentage, representing 13% of the total. We must highlight that the medication expense has fallen significantly in the last few years, because of cuts generated by the financial crisis in Spain. In our previous study7 the mean HD cost was €12,000 and in the current study, it is €6,000, i.e., half that of the previous study. ESA account for 35% the medication expense in HD. In the previous study, we allocated a cost of around €11 for every 1,000 units of erythropoietin, whereas in the current study, it was €2.4, and it has subsequently continued to decrease. Given that their use is almost universal and the doses are within a narrow range for most patients, the medication expense is quite homogenous in the HD population. The medication expense in ACKD was less than half that in HD or transplantation. In 2002, Pons et al.30 published a study of the medication costs in HD patients. The expense per patient/year was €3,084 for S4 patients and up to €4,224 for S5 patients, with ESA being responsible for 46.5% of these costs. These values are clearly higher than those recorded in the study that we carried out seven years later: €2,090 and €3,264, respectively, which illustrates the downward adjustment of the prices in recent years. The decrease in the cost of ESA is also explained mainly by the decreased medication cost in this population. In contrast to the decreased medication cost, particularly due to the lowering of ESA prices, medication expense has probably been the item with the greatest annual increase on previous years, due to the incorporation into the market of more expensive drugs, all related to mineral metabolism: new phosphate binders, vitamin D receptor activators, calcimimetics, etc. A patient who received three of these products with a mean dose may account for an expense of €25-30/day, i.e., an approximate increase of 70%-80% on the overall daily medication cost. Unfortunately, these financial approximations do not help us much in carrying out future estimations for medication. The imminent arrival of generic drugs to manage mineral metabolism, the continuous downward re-negotiation of prices and reductions or extensive regional competition result in a margin of uncertainty that is impossible to predict. Hospitalisation expenses As with our previous publication 7, we used the concept of DRG to report hospitalisation costs. This tool should be used as a reference and comparison framework in evaluating the quality of healthcare and the use of services Nefrologia 2014;34(4):458-68 originals provided by the hospitals. This system was developed by the government in order to establish a payment system for hospitals in the United States. It is based on a fixed quantity according to the specific DRG for each patient treated. The classification was carried out using international classification of disease codes (ICD-10) 19. The aim of this classification was to group diseases in order to assign a monetary value to each one, with the objective of improving hospital expense management. Although this method provides interesting information, unfortunately we do not have comparative data in the national setting for any RRT method, and we cannot guarantee that the coding of data taken from medical records is accurate to the real situation. We are only capable of carrying out comparisons in terms of hospitalisation rates and HD. The study published by Ploth et al.11 shows hospitalisation rates that are almost equivalent to ours: 32% of patients did not require hospitalisation during the study year. However, hospitalisation days vary a lot between different series: the shortest average was reported by Ploth et al.11: 5.7 days; in the series by Sehgal et al. 33, it increases to two weeks per patient per year; while in our study it was 18.7 days. However, there is nothing to indicate that these may be reference parameters, given the variability in circumstances that influence healthcare in each region or hospital. In fact, we did not observe a relationship between expenses, time and days hospitalised and initial patient comorbidity and this was probably due to socio-family circumstances or those related to different kinds of health deficiencies that lead to admissions or extended hospitalisation not explained strictly by medical reasons. Outpatient care The poor representation of outpatient costs reflects the lead role that nephrologists play in overall patient care, basically becoming the patients’ GPs. Furthermore, analysis of this aspect (consultations, complementary tests) shows enormous variability, given the social and health insecurity of patients in our setting, along with the alarming delays in appointments for studies and consultations, added to the difficulty of travel and family support, etc. The relationship between the cost of treatment, sociocultural factors and equal opportunities The association between sociocultural factors and cost is very difficult to establish, particularly in a chronic disease population that is elderly and has major comorbidities. In previous studies7,35, the cost of treatment was not clearly associated with comorbidity ranges or with the group of variables associated with sociocultural deprivation. This 465 originals is not surprising given that elderly patients, almost all of whom retired early, not having attended school and having worked in unskilled jobs had the most precarious health. But we must insist that, contrarily to what was expected (at least by the authors), none of these factors were associated with the cost of treatment. However, this statement warrants a response: the study population was very homogeneous in terms of sociocultural parameters, including comorbidity. Table 4 eloquently illustrates that more than two thirds of patients did not complete school and their work activity was unskilled. This may explain the lack of association between these parameters and cost. Very extensive series may be required, which include a more diverse population, in order to observe the effect of sociocultural deprivation on costs; although in studies carried out in the United States, we observed that the association between sociocultural factors and costs was weak in dialysis patients36. With regard to sociocultural status and access to transplantation, two extensive North American studies 37,38 reported that the most disadvantaged minorities had fewer opportunities to receive a transplant, with a certain inequality being observed in access to these programmes. In our case, we also observed that patients who received a transplant had the best sociocultural profile and that those who were on HD had the worst profile, with the profile being intermediate in ACKD patients. A priori, we must explain that patients on the transplant waiting list were younger and had better economic and cultural opportunities. With the aim of explaining this aspect, we carried out a logistic regression using sociocultural status as a dependent variable in a dichotomous format (sociocultural level: lower and middle-upper) and adjusting for age. It is interesting that the relative risk of the HD group was (odds ratio [95% CI]) 3.4 (2.0-6.1), P=.002 times greater than in the transplant group. When we created a matrix table that only included patients younger than 65 years of age (to homogenise the age of the groups), we also observed that transplant patients had a better sociocultural environment than HD patients of a similar age segment (X=19.2, P<.001). Study limitations Our study has limitations that we cannot avoid. Firstly, the data obtained from interviews are not strictly accurate or verifiable. Assuming this limitation, the surveys employed were validated and used previously 35,39, although with slight modifications in order to adapt them to the situation of HD patients. The study population was not necessarily representative of the national mean; although in age and distribution by sex it was similar, the proportion of diabetic patients was significantly higher and the sociocultural 466 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients environment probably has considerable interregional differences. The information obtained about the cost of treatment will be difficult to extrapolate to other regions and populations in absolute terms. The costs assigned to the different expense sections undoubtedly vary between health services and there is enormous variability in the allocation of expenses in different hospitals. Furthermore, we should bear in mind the cost reduction that there has been in some budgetary items, particularly in medication. But it continues to be very useful to have information about the costs between treatment methods or between different budget allocation items. In fact, we consider that the detailed information by cost component may be used as a reference for future studies or to carry out epidemiological estimations. PD, despite its limitations, has demonstrated cost-effective advantages compared to HD 21,23. Unfortunately, in our study, we did not manage to recruit a minimum number of patients to include this group. CONCLUSIONS We proved that the HD method is the most expensive procedure in all financial items, whereas the cost of ACKD patients and transplant patients is substantially lower. The similar cost between RTx and RPTx is notable. Unfortunately, the increase in age of the population that develops end-stage renal disease is a definitive limitation for access to transplantation. With these premises in mind, action at an earlier age is vital for preventing prolonged exposure to the adverse effects of chronic diseases, particularly diabetes 40,41. In this regard, we should aim to save financially by preventing kidney disease, both in primary care and in specific ACKD clinics. When patients reach advanced stages of the disease, early transplantation, giving full prominence to the living donor programme, must be an initiative that we must drive forward. Lastly, in spite of the health system in Spain being universal and supposedly egalitarian, this analysis invites us to think about whether a lower sociocultural status may undermine opportunities for access to renal transplantation. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. REFERENCES 1. U.S. Renal Data System. USRDS 2004 Annual Data Report: Atlas of End-Stage Renal Disease in the United States, National Institutes Nefrologia 2014;34(4):458-68 Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients of Health, National Institute of Diabetes and Digestive and Kidney Diseases. Bethesda, MD; 2004. Available at: http://www.usrds.org. Accessed at December 8th, 2006. 2007. 2. Otero A, de Francisco A, Gayoso P, Garcia F. Prevalence of chronic renal disease in Spain: results of the EPIRCE study. Nefrologia 2010;30:78-86. 3. Ritz E, Rychlik I, Locatelli F, Halimi S. End-stage renal failure in type 2 diabetes: A medical catastrophe of worldwide dimensions. Am J Kidney Dis 1999;34:795-808. 4. de Francisco AL. Sustainability and equity of renal replacement therapy in Spain. Nefrologia 2011;31:241-6. 5. S.E.N. Informe de Diálisis y Trasplante 2012. Accessed at: 24/12/2013. 6. Martin HR. Establishing and controlling chronic renal failure treatment costs. A pressing need. Nefrologia 2011;31:256-9. 7. Lorenzo V, Perestelo L, Barroso M, Torres A, Nazco J. [Economic evaluation of haemodialysis. Analysis of cost components based on patient-specific data]. Nefrologia 2010;30:403-12. 8. Parra Moncasi E, Arenas Jiménez MD, Alonso M, Martínez MF, Gámen Pardo A, Rebollo P, et al. Multicentre study of haemodialysis costs. Nefrologia 2011;31:299-307. 9. De Vecchi AF, Dratwa M, Wiedemann ME. Healthcare systems and end-stage renal disease (ESRD) therapies--an international review: costs and reimbursement/funding of ESRD therapies. Nephrol Dial Transplant 1999;14 Suppl 6:31-41. 10. Lee H, Manns B, Taub K, Ghali WA, Dean S, Johnson D, et al. Cost analysis of ongoing care of patients with end-stage renal disease: the impact of dialysis modality and dialysis access. Am J Kidney Dis 2002;40:611-22. 11. Ploth DW, Shepp PH, Counts C, Hutchison F. Prospective analysis of global costs for maintenance of patients with ESRD. Am J Kidney Dis 2003;42:12-21. 12. Klarenbach SW. Economic evaluation in renal disease. J Nephrol 2007;20:251-9. 13. Haller M, Gutjahr G, Kramar R, Harnoncourt F, Oberbauer R. Costeffectiveness analysis of renal replacement therapy in Austria. Nephrol Dial Transplant 2011;26:2988-95. 14. Klarenbach S, Manns B. Economic evaluation of dialysis therapies. Semin Nephrol 2009;29:524-32. 15. Howard K, Salkeld G, White S, McDonald S, Chadban S, Craig JC, et al. The cost-effectiveness of increasing kidney transplantation and home-based dialysis. Nephrology (Carlton) 2009;14:123-32. 16. Wong G, Howard K, Chapman JR, Chadban S, Cross N, Tong A, et al. Comparative survival and economic benefits of deceased donor kidney transplantation and dialysis in people with varying ages and co-morbidities. PLoS One 2012;7:e29591. 17. Hodgson TA, Meiners MR. Cost-of-illness methodology: a guide to current practices and procedures. Milbank Mem Fund Q Health Soc 1982;60:429-62. 18. Boletín Oficial de Canarias Num 50. Available at: https://sede.gobcan.es/cpji/boc. Accessed at: 13/03/2013. 2013. 20-7-2013. 19. Registro de Altas de los Hospitales Generales del Sistema Nacional de Salud. Ministerio de Sanidad y Política Social. 2013. Available at: http://www.msssi.gob.es/. 20.Thompson SG, Barber JA. How should cost data in pragmatic randomised trials be analysed? BMJ 2000;320:1197-200. 21. Arrieta J, Rodríguez-Carmona A, Remón C, Pérez-Fontán M, OrNefrologia 2014;34(4):458-68 originals tega F, Sánchez Tomero JA, et al. Peritoneal dialysis is the best cost-effective alternative for maintaining dialysis treatment. Nefrologia 2011;31:505-13. 22. De Vecchi AF, Dratwa M, Wiedemann ME. Healthcare systems and end-stage renal disease (ESRD) therapies--an international review: costs and reimbursement/funding of ESRD therapies. Nephrol Dial Transplant 1999;14 Suppl 6:31-41. 23. Arrieta J, Rodríguez-Carmona A, Remón C, Pérez-Fontán M, Ortega F, Sánchez-Tomero JA, et al. Cost comparison between haemodialysis and peritoneal dialysis outsourcing agreements. Nefrologia 2012;32:247-8. 24. Villa G, Rodríguez-Carmona A, Fernandez-Ortiz L, Cuervo J, Rebollo P, Otero A, et al. Cost analysis of the Spanish renal replacement therapy programme. Nephrol Dial Transplant 2011;26:3709-14. 25.Lamas Barreiro JM, Alonso SM, Saavedra Alonso JA, Gandara MA. Costs and added value of haemodialysis and peritoneal dialysis outsourcing agreements. Nefrologia 2011;31:656-63. 26.Honeycutt AA, Segel JE, Zhuo X, Hoerger TJ, Imai K, Williams D. Medical costs of CKD in the Medicare population. J Am Soc Nephrol 2013;24:1478-83. 27. Hernández-Jaras J, García H, Bernat A, Cerrillo V. [Approximation to cost analysis of various types of hemodialysis using relative value units]. Nefrologia 2000;20:284-90. 28. Lamas J, Alonso M, Saavedra J, García-Trío G, Rionda M, Ameijeiras M. [Costs of chronic dialysis in a public hospital: myths and realities]. Nefrologia 2001;21:283-94. 29. Palmer AJ, Annemans L, Roze S, Lamotte M, Rodby RA, Cordonnier DJ. An economic evaluation of irbesartan in the treatment of patients with type 2 diabetes, hypertension and nephropathy: cost-effectiveness of Irbesartan in Diabetic Nephropathy Trial (IDNT) in the Belgian and French settings. Nephrol Dial Transplant 2003;18:2059-66. 30. Lamping DL, Constantinovici N, Roderick P, Normand C, Henderson L, Harris S, et al. Clinical outcomes, quality of life, and costs in the North Thames Dialysis Study of elderly people on dialysis: a prospective cohort study. Lancet 2000;356:1543-50. 31. Icks A, Haastert B, Gandjour A, Chernyak N, Rathmann W, Giani G, et al. Costs of dialysis--a regional population-based analysis. Nephrol Dial Transplant 2010;25:1647-52. 32. Arrieta J. Evaluación económica del tratamiento sustitutivo renal (hemodiálisis, diálisis peritoneal y trasplante) en España. Nefrologia 2010;1(Suppl 1):37-47. 33. Sehgal AR, Dor A, Tsai AC. Morbidity and cost implications of inadequate hemodialysis. Am J Kidney Dis 2001;37:1223-31. 34. Jotkowitz AB, Rabinowitz G, Raskin SA, Weitzman R, Epstein L, Porath A. Do patients with diabetes and low socioeconomic status receive less care and have worse outcomes? A national study. Am J Med 2006;119:665-9. 35. Beddhu S, Bruns FJ, Saul M, Seddon P, Zeidel ML. A simple comorbidity scale predicts clinical outcomes and costs in dialysis patients. Am J Med 2000;108:609-13. 36. Hirth RA, Held PJ, Orzol SM, Dor A. Practice patterns, case mix, Medicare payment policy, and dialysis facility costs. Health Serv Res 1999;33:1567-92. 37. Kasiske BL, London W, Ellison MD. Race and socioeconomic factors influencing early placement on the kidney transplant waiting list. J Am Soc Nephrol 1998;9:2142-7. 467 originals 38.Sandhu GS, Khattak M, Pavlakis M, Woodward R, Hanto DW, Wasilewski MA, et al. Recipient’s unemployment restricts access to renal transplantation. Clin Transplant 2013;27:598-606. 39. Lopez-Bastida J, Oliva-Moreno J, Perestelo-Perez L, Serrano-Aguilar P. The economic costs and health-related quality of life of people with HIV/AIDS in the Canary Islands, Spain. BMC Health Serv Res 2009;9:55. Víctor Lorenzo-Sellares et al. Cost analysis in kidney patients 40. Lorenzo V, Boronat M, Saavedra P, Rufino M, Maceira B, Novoa FJ, et al. Disproportionately high incidence of diabetes-related end-stage renal disease in the Canary Islands. An analysis based on estimated population at risk. Nephrol Dial Transplant 2010;25:2283-8. 41.Lorenzo V, Boronat M. [Terminal kidney disease associated with diabetes in the Canary Islands: a public health problem with high economic cost and human suffering]. Nefrologia 2010;30:381-4. Sent to review: 21 Feb. 2014 | Accepted: 19 Apr. 2014 468 Nefrologia 2014;34(4):458-68 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society originals During the pre-dialysis stage of chronic kidney disease, which treatment is associated with better survival in dialysis? Francisco Caravaca, Raúl Alvarado, Guadalupe García-Pino, Rocío Martínez-Gallardo, Enrique Luna Servicio de Nefrología. Hospital Infanta Cristina. Badajoz (Spain) Nefrologia 2014;34(4):469-76 doi:10.3265/Nefrologia.pre2014.Apr.12277 ABSTRACT Introduction: Specialised care of patients in advanced stages of chronic kidney disease (CKD) is associated with better survival in dialysis, but it is not known which treatments specifically favour this outcome. Objectives: To analyse normal treatment in advanced stages of CKD and establish which treatments are associated with better survival in dialysis as well as their relationship with causes of death. Material and method: Cohort, prospective observational study of 591 patients who started dialysis (491 haemodialysis and 100 peritoneal dialysis), who had previously been controlled in the CKD clinic. The treatments analysed were: antihypertensive treatments, statins, platelet antiaggregants, xanthine oxidase inhibitors, correction of metabolic acidosis, treatment with (calcium or noncalcium) phosphate binders, vitamin D (calcitriol or paricalcitol), erythropoietin and the availability of an internal arteriovenous fistula (IAVF). The independent association of each of these treatments with mortality in dialysis was analysed using Cox regression models adjusted for age, sex, pre-dialysis monitoring time, renal function at the start of dialysis, comorbidity, serum albumin and C-reactive protein, and with stratification of the type of dialysis. Results: With a median follow-up period of 28 months, the total number of patients who died was 191 (32%). In the multivariate models, we observed that, in addition to age, the comorbidity index, serum albumin, predialysis treatment with angiotensin-converting-enzyme inhibitors and/or angiotensin II receptor antagonists, correction of acidosis with sodium bicarbonate and IAVF at the start of haemodialysis were significantly associated with better survival in dialysis. We did not observe differences in causes of death among the different treatments analysed. Conclusion: These results suggest a potential delayed benefit of some treatments in pre-dialysis stages on the outcome of dialysis. Furthermore, beginning dialysis without an IAVF, and therefore the need for intravenous catheters, worsens prognosis in these patients. ¿Qué intervenciones terapéuticas durante el estadio prediálisis de la enfermedad renal crónica se asocian a una mejor supervivencia en diálisis? RESUMEN Introducción: El cuidado especializado de los pacientes en estadios avanzados de la enfermedad renal crónica (ERC) se asocia a una mejor supervivencia en diálisis, pero se desconoce qué tratamientos favorecen específicamente esta evolución. Objetivos: Analizar las intervenciones terapéuticas habituales en el estadio de ERC avanzada y establecer cuáles de ellas se asocian a una mejor supervivencia en diálisis y su relación con las causas de muerte. Material y métodos: Estudio de cohortes, prospectivo y de observación, que incluyó a 591 pacientes que iniciaron diálisis (491 hemodiálisis y 100 diálisis peritoneal), que habían sido controlados previamente en la consulta de ERC. Las intervenciones terapéuticas analizadas fueron: tratamientos antihipertensivos, estatinas, antiagregantes plaquetarios, inhibidores de la xantina-oxidasa, corrección de la acidosis metabólica, tratamiento con captores de fósforo (cálcicos o no), vitamina D (calcitriol o paricalcitol), eritropoyetina y disponibilidad de fístula arterio-venosa interna (FAVI). La asociación independiente de cada uno de estos tratamiento con la mortalidad en diálisis fue analizada mediante modelos de regresión de Cox con ajuste a edad, sexo, tiempo de seguimiento prediálisis, función renal al inicio de diálisis, comorbilidad, albumina sérica y proteína C reactiva, y con estratificación al tipo de diálisis. Resultados: Con una mediana de seguimiento de 28 meses, la cifra total de fallecidos fue de 191 (32 %). En los modelos multivariantes se observó que, además de la edad, el índice de comorbilidad y la albúmina sérica, el tratamiento prediálisis con inhibidores de la enzima de conversión y/o antagonistas de los receptores de la angiotensina, la corrección de la acidosis con bicarbonato sódico y la FAVI al inicio de la hemodiálisis se asociaron de forma significativa con una mejor supervivencia en diálisis. No se observaron diferencias en las causas de muerte entre los diferentes tratamientos analizados. Conclusión: Estos resultados sugieren un posible beneficio diferido de algunos tratamientos en estadios prediálisis sobre la evolución en diálisis. Además, el inicio de hemodiálisis sin una FAVI, y por tanto la necesidad de utilización de catéteres endovenosos, empeora el pronóstico de estos pacientes. Keywords: Mortality. Dialysis. Angiotensin-converting enzyme inhibitors. Pre-dialysis. Palabras clave: Mortalidad. Diálisis. Inhibidores de la enzima de conversión de la angiotensina. Prediálisis. Correspondence: Francisco Caravaca Servicio de Nefrología. Hospital Infanta Cristina. Avda. Elvás, S/N. 06080, Badajoz. (Spain). [email protected] INTRODUCTION Mortality remains very high in dialysis patients. Age and comorbidity are the main determining factors of mortality in 469 originals this population, but these factors can obviously not or hardly be changed. Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis Table 1. Clinical characteristics and treatments received by patients included in the study An epidemiological feature of dialysis patients is the lack of association between classic cardiovascular risk factors and mortality1. Moreover, the few randomised studies carried out in this population have not demonstrated clear benefits on survival with the use of various drugs proven to be useful in the non-uraemic population or with other therapeutic measures based on sound pathophysiological principles2. Total no. of patients Moreover, some studies have warned us about the potential risk of drugs commonly used in chronic kidney disease (CKD), such as erythropoietin (EPO)3 or calcium salts4, which adds even more difficulty and confusion to the management of these patients. Davies comorbidity index, absent/low to medium/high The specialised care of pre-dialysis patients in advanced stages of CKD is unanimously considered to be a factor that benefits survival in dialysis5,6. In these advanced chronic kidney disease (ACKD) clinics, many treatments are usually carried out, such as controlling blood pressure, correcting over-hydration, metabolic acidosis, mineral and bone disorders and anaemia, creating vascular access and choosing when to start dialysis, etc., but the importance of each of these treatments and the benefits they can bring in terms of dialysis patient survival is unknown. Serum albumin, g/dl We carried out this prospective study with the objective of analysing the normal treatments for ACKD and establishing which of them are associated with greater survival in dialysis, as well as their relationship with causes of death. MATERIAL AND METHOD We included 591 patients with the demographic and clinical characteristics that are displayed in Table 1. Inclusion criteria were as follows: having begun dialysis treatment at the Hospital Infanta Cristina de Badajoz during the period between October 1999 and January 2012, and having previously been monitored in the ACKD clinic of the same hospital. We did not exclude any patients. We started haemodialysis (HD) in 491 patients and peritoneal dialysis (PD) in 100. There were no pre-dialysis kidney transplantations. The information on the treatment that the patients were receiving was obtained by anamnesis and a review of medical records. The treatments used during the pre-dialysis stage that were analysed in this study were: treatment with angiotensinconverting enzyme inhibitors (ACEI) and/or angiotensin receptor blockers (ARBs), diuretics, calcium channel 470 591 Age, years 61±15 Sex, male/female 329/262 Diabetes, % 32% ACKD follow-up time, median days 318 (125-657)a Patients with ACKD follow-up >90 days, % 83 255/274/62 HD/PD, no. patients 491/100 Glomerular filtration rate at the start of dialysis, ml/min/1.73m2 7.8±1.8 C-reactive protein, mg/l 3.85±0.51 3.79 (1.35-9.03)a ACEI/ARBs, % 73 Calcium channel blockers, % 50 Diuretics, % 60 Beta-blockers, % 23 Statins, % 53 Antiplatelet drugs, % 28 Xanthine oxidase inhibitors, % 23 Sodium bicarbonate treatment, % 46 Phosphate binder, % 91 Phosphate binder with calcium, % 71 Treatment with vitamin D, % 13 Treatment with EPO, % 71 AVF, % HD patients 51 ARBs: angiotensin receptor blockers, PD: peritoneal dialysis, EPO: erythropoietin, ACKD: advanced chronic kidney disease, AVF: arteriovenous fistula, HD: haemodialysis, ACEI: angiotensin-converting enzyme inhibitors. a Median and interquartile range. blockers, beta-blockers, statins, antiplatelet drugs, xanthine oxidase inhibitors, correction of metabolic acidosis with sodium bicarbonate, treatment with (calcium or noncalcium) phosphate binders, calcium salts, active vitamin D (calcitriol or paricalcitol) and anaemia correction by EPO. Furthermore, we included an internal arteriovenous fistula (IAVF) in our treatment, and this was usable at the time dialysis began. The covariates included to adjust survival models were: age, sex, Davies comorbidity index (three subgroups: no Nefrologia 2014;34(4):469-76 Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis comorbidity, mild to moderate, and severe comorbidity) , diagnosis of diabetes mellitus, serum albumin concentrations (bromocresol green, Advia Chemistry, Siemens Healthcare Diagnostics) and C-reactive protein (high sensitivity by chemiluminescence immunoassay in the solid phase, Immulite, Siemens). As potential confounding variables, we also included the glomerular filtration rate (MDRD-4) at the start of dialysis and the follow-up time in the ACKD clinic (greater or less than 90 days). The lack of a functioning IAVF in patients included in this study who started HD may have been due to one of the following reasons: failure (thrombosis), its rejection by the patient or insufficient pre-dialysis follow-up time. Patients were followed-up with regard to their outcomes in dialysis, with death due to all causes being the only study event. The follow-up period began with the first dialysis session and patients were censored (non-informative censoring) for the end of data collection (September 2012), loss to follow-up and renal transplantation. We also recorded the cause of death, establishing five etiological groups: sudden death, death from cardiovascular, infectious, tumour and other causes. To analyse whether there was an association between the different pre-dialysis treatments and survival in dialysis, we used Kaplan-Meier curves (univariate study) and Cox multivariate proportional hazards models, with the calculation of the instantaneous hazard rates (hazard ratio) and their 95% confidence intervals. Covariates in multivariate models were selected automatically, using the backwards progressive conditional elimination process. Due to the potential confounding by indication in the inclusion of PD and HD patients, who not only had age and comorbidity differences, but also had differences in other characteristics that were not recorded as variables but nonetheless had a potential influence on survival, such as socio-economic and cultural level or the degree of dependency, the analyses were stratified according to the initial form of treatment (HD or PD). The analysis of survival and stratification between PD and HD was in any case considered by intention-to-treat, independently of the time that the patient would have remained on one or another dialysis technique. For comparison of continuous variables between patients who survived or died, we used Student’s t-test or the Mann-Whitney test, depending on the characteristics of the variable distribution. The χ2 test was used to compare categorical variables between subgroups. Nefrologia 2014;34(4):469-76 originals The data were presented as a mean ± standard deviation or the median and interquartile ranges. A P value less than .05 was considered to be statistically significant. For statistical analyses and creating graphs, we used the SPSS version 15.0 software (SPSS, Chicago, USA) and STATA version 11.1 (Stata Corporation, Texas, USA). RESULTS Mortality in dialysis With a median follow-up of 28 months (interquartile ranges: 13-50 months), the total number of deaths was 191 (32%) and estimated median survival was 82 months (95% confidence interval: 56-108 months). The demographic, clinical and biochemical characteristics of the patients who survived and died are displayed in Table 2. As well as the factors that were very much expected to be associated with mortality such as age, comorbidity and serum albumin and C-reactive protein concentrations, we note the low mean follow-up time in the ACKD clinics of the patients who died (Table 2). We also observed significant differences in pre-dialysis treatments between those who survived and those who died, which highlights the positive association between survival and ACEI/ARBs, beta-blockers, statins, sodium bicarbonate and phosphate binders, and even calcium salts. By contrast, the association was negative for survival with diuretics and at the limit of significance with antiplatelet drugs. We did not observe differences in the percentage of EPO, vitamin D or xanthine oxidase inhibitor prescription between those who survived and those who did not. The glomerular filtration rate at which dialysis began was significantly higher in patients who died and the percentage of patients with an IAVF was significantly lower in this same subgroup (Table 2). Patients whose initial treatment was with PD had better survival than those treated with HD (Figure 1), although it is important to highlight again that there were major differences between both subgroups with regard to age, comorbidity and other factors that potentially influenced survival that were not recorded in this study, such as socio-economic, cultural and dependency levels. Causes of death according to pre-dialysis treatments Figure 2 displays the causes of death grouped into five aetiological sections (sudden death, cardiovascular, infection, tumour and other causes), according to the type of initial dialysis and some treatments carried out in the pre-dialysis 471 Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis originals Table 2. Clinical characteristics and treatments received by patients who survived or died during the study period Survivors 400 57±16 57 Deaths 191 70±10 54 <0.0001 ns 344 (133-704)a 257 (99-561)a 0.02 26 43 <0.0001 53/40/7 22/59/19 <0.0001 No. patients Age Sex, % males Pre-dialysis follow-up time, days Diabetes, % Comorbidity index, % group absent/low to medium/high comorbidity Serum albumin, g/dl C-reactive protein, mg/l 3.93±0.48 P 3.68±0.52 <0.0001 2.97 (1.03-7.37) 4.69 (2.30-15.11) <0.0001 ACEI/ARBs, % 79 61 <0.0001 Diuretics, % 56 70 0.001 Calcium channel blockers, % 48 55 0.113 Beta-blockers, % 26 19 0.032 Statins, % 56 46 0.020 Treatment with EPO, % 71 71 ns Treatment with vitamin D, % 14 13 ns Antiplatelet drugs, % 26 33 0.06 Xanthine oxidase inhibitors, % 24 20 ns Treatment with sodium bicarbonate, % 51 35 < 0.0001 Phosphate binders,% 93 86 0.008 Calcium binders, % 75 63 0.003 7.61±1.67 8.22±1.93 <0.0001 59 % 36 % <0.0001 Glomerular filtration rate at the start of dialysis, ml/min/1.73m2 Functioning AVF, % patients who started HD a a ARBs: angiotensin receptor blockers, EPO: erythropoietin, AVF: arteriovenous fistula, HD: haemodialysis, ACEI: angiotensin-converting enzyme inhibitors, ns: not significant. a Median and interquartile range. stage. Those of cardiovascular and infectious origin were the most common causes of mortality. The only significant difference observed was between PD and HD (P=.02), with there being an absence of sudden death in PD patients and on the other hand, a greater proportion of death from tumours, due to a lack of oncological control of myeloma and leukaemia that were already related to the origin of renal failure. We did not observe significant differences in the cause of death between those treated and those not treated with EPO, vitamin D or calcium salts. The differences in the cause of death between patients who began HD with or without an IAVF were not significant either, although there was a higher rate of death from infectious aetiologies in those who did not possess an IAVF. 472 Analysis of survival and its association with the study variables In the Cox stratified regression analysis according to the initial type of dialysis (Table 3) we observed that, as well as age, the comorbidity index and serum albumin, pre-dialysis treatment with ACEI/ARBs and the correction of acidosis with sodium bicarbonate were positively associated with survival in dialysis. We also note the positive and significant association between the availability of an IAVF at the start of HD and survival. By contrast, higher renal function at the start of dialysis was associated with worse survival. Figures 3 and 4 display the dialysis survival curves of the patients who had been treated and those who had not been treated with ACEI/ARBs during the pre-dialysis period. Figure 5 displays the survival curves of patients who started HD with or without an IAVF. Nefrologia 2014;34(4):469-76 Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis 1.0 Due to strong confounding by indication in this study, we cannot claim that there is causality between the direct therapeutic effects of these drugs and improved survival in dialysis patients, even after adjustment with the confounding variables, but we believe that the data provide information that could prove useful in the prediction of outcomes in dialysis patients. PD Survival 0.8 0.6 HD The effect of treatment with ACEI or ARBs on ACKD or dialysis patient survival is controversial. These drugs may have positive effects on residual renal function, vascular access and the uraemic myocardium7, which in turn may be reflected in better survival8, although other studies have not been able to demonstrate this benefit9. 0.4 0.2 0 Log-rank = 25.15 P<0.0001 0 50 100 150 200 Time on dialysis, months HD n =491 270 123 56 PD n =100 57 22 11 18 6 5 Figure 1. Kaplan-Meier survival curves in patients who started haemodialysis or peritoneal dialysis. The number of patients in each group at the start of each 25-month period is also displayed. PD: peritoneal dialysis, HD: haemodialysis, Log-rank: log rank estimated by the Mantel-Haensel test. DISCUSSION Mortality in dialysis patients continues to be very high. Some characteristics of CKD such as the growing severity of its complications as renal failure progresses, as well as accumulative adverse effects, some of them irreversible, could help us to understand this disconcerting fact. As such, the monitoring and treatment of the disease in less advanced stages may have a major influence on the survival of patients who reach more advanced stages. This is a hypothesis that would explain better survival in dialysis of patients who were monitored and treated in ACKD clinics. The results of this study show that there are various predialysis treatments that are significantly associated with a better outcome in dialysis patients, but the only ones to remain in the models adjusted for age, sex, comorbidity, dialysis type and other prognosis markers were treatment with ACEI/ARBs, metabolic acidosis correction with sodium bicarbonate and the introduction of an IAVF in those who began HD. By contrast, we did not observe that any of the treatments analysed in adjusted models were associated with a worse outcome or any specific cause of death. Nefrologia 2014;34(4):469-76 originals The association between ACEI/ARBs use in pre-dialysis and survival in PD and HD patients is an original result of this study. A hypothesis to explain these findings may be based on a potential survival bias, that is, patients who required, tolerated and survived treatment with ACEI/ARBSs in the pre-dialysis period form a select group with a greater probability of survival in dialysis. However, this hypothesis seems unlikely, since we also observed better pre-dialysis survival in those treated with ACEI/ARBs (observations not published). Another hypothesis to explain this delayed association may be related to a “legacy effect”. This term was originally coined to PD HD ACEI/ARBs + ACEI/ARBs EPO + EPO Calcium + Calcium Vitamin D + Vitamin D AVF + AVF 0 25 50 75 100 % died n Sudden n CV n Infection n Tumour n Other Figure 2. Causes of death according to the dialysis type, or some pre-dialysis treatments, or the availability of an arteriovenous fistula in those who started haemodialysis. ARBs: angiotensin receptor blockers, CV: cardiovascular, PD: peritoneal dialysis, EPO: erythropoietin, AVF: arteriovenous fistula, HD: haemodialysis, ACEI: angiotensin-converting enzyme inhibitors. 473 originals Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis Table 3. Cox multivariate regression models on mortality in dialysis Variable Hazard ratio IC 95 % hazard ratio P Age, years 1.036 1.022-1.051 <0.0001 Comorbidity index (0,1,2) 1.432 1.121-1.829 0.004 Serum albumin, g/dl 0.706 0.530-0.941 0.018 ACEI/ABRs (0.1) 0.660 0.487-0.895 0.007 Treatment with sodium bicarbonate (0.1) 0.723 0.530-0.985 0.040 IAVF (0.1) 0.678 0.494-0.931 0.016 Glomerular filtration rate at the start of dialysis, ml/min 1.100 1.021-1.185 0.013 ARBs: angiotensin receptor blockers, CI: confidence interval, IAVF: internal arteriovenous fistula, ACEI: angiotensin-converting enzyme inhibitors. Outside the model: sex, diabetes, C-reactive protein, calcium channel blockers, erythropoietin, vitamin D, antiplatelet drugs, xanthine oxidase inhibitors, diuretics, beta-blockers, phosphate binders, calcium salts, time in advanced chronic kidney disease clinic and statins (the latter was on the limit of significance, hazard ratio =0.748, P=.058). describe the positive effect of good metabolic control during the initial stages of diabetes on the subsequent outcome and its complications. There has also been speculation about the possibility that this same legacy effect could be achieved with the control of high blood pressure or with the use of ACEI/ARBs11, which is a benefit of survival that could be maintained beyond drug interruption, and it is therefore more difficult to appreciate it clinically. Metabolic acidosis in CKD has negative effects on the state of nutrition, mineral and bone disease and inflammation, and is associated with worse survival12. The correction of acidosis with sodium bicarbonate has demonstrated not only that it improves the state of nutrition, but that it also has very positive effects on maintaining renal function. In this study, the correction of acidosis with sodium bicarbonate was independently associated with better survival in dialysis. However, the potential confounding by indication also prevented the causality of this association from being confirmed. Some confounding factors that may influence this association are the decreased tendency for acidosis of diabetic patients with CKD13, or the association between acidosis and treatment with ACEI/ARBs due to type IV renal tubular acidosis or the impossibility of prescribing antacids in those who were treated for a brief period of time in the ACKD clinic. All of these confounding variables were taken into account in the multivariate regression analyses (diagnosis of diabetes, ACEI/ARB treatment and pre-dialysis follow-up time), and treatment with bicarbonate maintained statistical significance. Starting HD with an IAVF improved vital prognosis 14. According to these studies, we also observed better survival 474 in patients with a functioning IAVF at the start of HD, and this association was independent of other confounding factors (age, sex, comorbidity, drugs, etc.) Although the causes of death in those who initiated HD with or without IAVF were not significantly different, a greater percentage of deaths due to infection was observed, perhaps in relation to the more frequent use of endovascular catheters. The renal function with which these patients started dialysis was another determining factor of survival, but to the contrary of what was expected, the association was negative. In accordance with observations of other authors 15, it is likely that a higher glomerular filtration rate at the start of dialysis reflects a poor general patient condition, higher intolerance to uraemia, especially that related to states of over-hydration and the development of heart failure. It is also important to point out that when a patient from our study required the (urgent) non-scheduled initiation of dialysis due to any of these complications, the renal function figure that was taken was that of the last scheduled test, and therefore, this higher glomerular filtration rate would not reflect real renal function at the time of the first dialysis session. This study has limitations mainly derived from the aforementioned confounding biases (indication and survival). Although the effect of these biases aims to correct itself by stratification and adjustment of the models with the main confounding variables, we cannot rule out the possibility of other variables that we have not considered having a significant influence on the end results. Nefrologia 2014;34(4):469-76 Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis originals 1.0 1.0 With ACEI/ARBs 0.8 0.6 Without ACEI/ARBs 0.4 0.2 0 0.6 Survival Survival 0.8 0.2 Log-rank = 10.16 P=0.001 0 With ACEI/ARBs 0.4 0 Log-rank = 10.46 P=0.001 0 20 40 60 80 100 120 Time on dialysis, months n= 358 Without ACEI/ ARBs 50 100 150 Time on dialysis, months 200 198 91 38 11 4 72 32 18 7 1 With ACEI/ARBs n =74 49 1711631 Without ACEI/ARBs n =26 20 126 431 With ACEI/ARBs Figure 3. Kaplan-Meier survival curves in patients who started peritoneal dialysis and were treated or not with angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers. The number of patients in each group at the start of each 20-month period is also displayed. ARBs: angiotensin receptor blockers, ACEI: angiotensinconverting enzyme inhibitors, Log-rank: log rank estimated by the Mantel-Haensel test. Figure 4. Kaplan-Meier survival curves in patients who started haemodialysis and were treated or not with angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers. The number of patients in each group at the start of each 25-month period is also displayed. ARBs: angiotensin receptor blockers, ACEI: angiotensinconverting enzyme inhibitors, Log-rank: log rank estimated by the Mantel-Haensel test. Without ACEI/ARBs n =132 1.0 Another limitation is that all patients studied were from the same hospital, with certain treatment criteria, which prevents us from guaranteeing the reproduction of the results with different treatment criteria. These results suggest a potential delayed benefit (legacy effect) of some treatment in pre-dialysis stages on the subsequent evolution of dialysis patients. In addition, starting HD without an IAVF, with the resulting need for intravenous catheters, could be related to worse prognosis. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. Nefrologia 2014;34(4):469-76 Started HD with AVF Survival In conclusion, there are differences in pre-dialysis treatments of patients who survive or die on dialysis. The most significant differences in models that are stratified to the type of dialysis and to the main confounding factors are: treatment with ACEI/ARBs, treatment with sodium bicarbonate and having a usable IAVF at the time of the first HD session. 0.8 0.6 0.4 0.2 0 Started HD without AVF Log-rank = 22.44 P<0.0001 0 50 100150200 Time on dialysis, months With FAV n = 248148 74 33 8 2 10 3 Whithout FAV n = 243122 49 23 Figure 5. Kaplan-Meier survival curves in patients who started haemodialysis and had or did not have a functioning arteriovenous fistula. The number of patients in each group at the start of each 25-month period is also displayed. AVF: arteriovenous fistula, HD: haemodialysis, Log-rank: log rank estimated by the Mantel-Haensel test. 475 originals Francisco Caravaca et al. Pre-dialysis treatment and survival in dialysis REFERENCES 1. Kopple JD. The phenomenon of altered risk factor patterns or reverse epidemiology in persons with advanced chronic kidney failure. Am J Clin Nutr 2005;81:1257-66. 2. Kramann R, Floege J, Ketteler M, Marx N, Brandenburg VM. Medical options to fight mortality in end-stage renal disease: a review of the literature. Nephrol Dial Transplant 2012;27:4298-307. 3. Fishbane S, Besarab A. Mechanism of increased mortality risk with erythropoietin treatment to higher hemoglobin targets. Clin J Am Soc Nephrol 2007;2:1274-82. 4. Block GA, Spiegel DM, Ehrlich J, Mehta R, Lindbergh J, Dreisbach A, et al. Effects of sevelamer and calcium on coronary artery calcification in patients new to hemodialysis. Kidney Int 2005;68:1815-24. 5. Ifudu O, Dawood M, Homel P, Friedman EA. Excess morbidity in patients starting uremia therapy without prior care by a nephrologist. Am J Kidney Dis 1996;28:841-5. 6. Bradbury BD, Fissell RB, Albert JM, Anthony MS, Critchlow CW, Pisoni RL, et al. Predictors of early mortality among incident US hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Clin J Am Soc Nephrol 2007;2:89-99. 7. Cravedi P, Remuzzi G, Ruggenenti P. Targeting the renin angiotensin system in dialysis patients. Semin Dial 2011;24:290-7. 8. Chan KE, Ikizler TA, Gamboa JL, Yu C, Hakim RM, Brown NJ. Combined angiotensin-converting enzyme inhibition and re- ceptor blockade associate with increased risk of cardiovascular death in hemodialysis patients. Kidney Int 2011;80:978-85. 9. Ahmed A, Fonarow GC, Zhang Y, Sanders PW, Allman RM, Arnett DK, et al. Renin-angiotensin inhibition in systolic heart failure and chronic kidney disease. Am J Med 2012;125:399-410. 10. Holman RR, Paul SK, Bethel MA, Matthews DR, Neil HA. 10year follow-up of intensive glucose control in type 2 diabetes. N Engl J Med 2008;359:1577-89. 11. Volpe M, Cosentino F, Tocci G, Palano F, Paneni F. Antihypertensive therapy in diabetes: the legacy effect and RAAS blockade. Curr Hypertens Rep 2011;13:318-24. 12. Kovesdy CP, Anderson JE, Kalantar-Zadeh K. Association of serum bicarbonate levels with mortality in patients with non-dialysis-dependent CKD. Nephrol Dial Transplant 2009;24:1232-7. 13. Caravaca F, Arrobas M, Pizarro JL, Espárrago JF. Metabolic acidosis in advanced renal failure: differences between diabetic and nondiabetic patients. Am J Kidney Dis 1999;33:892-8. 14. Pisoni RL, Arrington CJ, Albert JM, Ethier J, Kimata N, Krishnan M, et al. Facility hemodialysis vascular access use and mortality in countries participating in DOPPS: an instrumental variable analysis. Am J Kidney Dis 2009;53:475-91. 15. Susantitaphong P, Altamimi S, Ashkar M, Balk EM, Stel VS, Wright S, et al. GFR at initiation of dialysis and mortality in CKD: a meta-analysis. Am J Kidney Dis 2012;59:829-40. Sent to review: 15 Sep. 2013 | Accepted: 24 Apr. 2014 476 Nefrologia 2014;34(4):469-76 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society originals Fluid therapy and iatrogenic hyponatraemia risk in children hospitalised with acute gastroenteritis: prospective study Marciano Sánchez-Bayle1, Raquel Martín-Martín2, Julia Cano-Fernández1, Enrique Villalobos-Pinto1 1 Sección de Pediatría. Hospital Niño Jesús. Madrid (Spain); 2 Servicio de Pediatría. CS Reina Victoria. Madrid (Spain) Nefrologia 2014;34(4):477-82 doi:10.3265/Nefrologia.pre2014.May.12257 ABSTRACT Objective: The purpose of this study is to analyse whether the use of hypotonic fluids increases the risk of iatrogenic hyponatraemia in children hospitalised with acute gastroenteritis (AGE). Patients and methods: Prospective study carried out on 205 patients with ages ranging from 1 to 28 months and admitted with a diagnosis of mild or moderate dehydration due to AGE and treated with intravenous hypotonic fluids in a paediatric department in Madrid (Spain). The degree of dehydration at presentation was estimated using standard clinical measures. 198 children received 0.3 % glucosaline solution and in 7 patients, with baseline hypernatraemia, 0.2 % gluco-hyposaline solution was administered. We analysed the results according to whether children were hyponatraemic, normonatraemic or hypernatraemic at presentation. The blood and urine samples were analysed and the concentration of sodium and fractional sodium excretion (EFNa) before and after intervention were considered as outcome measures. Results: The 205 patients included in the study were distributed in 3 groups according to the baseline natraemia results. In 37 cases we detected hyponatraemia (18.04%), in 133 cases isonatraemia (64.87%) and in 35 children hypernatraemia (17.07%). After administering hypotonic fluids we detected a significant difference between initial and final natraemia in all groups; in the group with hyponatraemia, sodium increased and in the groups with iso and hypernatraemia, sodium slightly decreased. A significant correlation between the EFNa and the evolution of natraemia was found. No cases of hyponatraemia post-infusion were seen and there was no correlation between free water administered and natraemia evolution. Conclusions: Results show that the use of hypotonic fluids does not increase the risk of hospital acquired hyponatraemia in hospitalised children with normal renal function. Our children with gastroenteritis did not develop hyponatraemia even though they were all treated with hypotonic intravenous solutions. Intravenous rehydration and acquired hyponatraemia in hospitalized children with gastroenteritis: prospective study RESUMEN Objetivo: Determinar si la utilización de sueros hipotónicos supone un riesgo en la aparición de hiponatremia iatrogénica en los niños hospitalizados por gastroenteritis aguda (GEA). Pacientes y método: Estudio prospectivo realizado con 205 pacientes de edades comprendidas entre 1 y 28 meses e ingresados con diagnóstico de deshidratación leve o moderada por GEA para recibir sueroterapia en la sección de lactantes de un hospital pediátrico de Madrid (España). El grado de deshidratación inicial se estimó con mediciones clínicas estándar. El suero administrado fue glucosalino 0,3 % en 198 casos y en los 7 casos restantes, todos con hipernatremia inicial, se administró suero glucohiposalino 0,2 %. Se analizó la respuesta a los líquidos intravenosos según si el niño se hallaba normo, hipo o hipernatrémico antes de iniciar el tratamiento. Las cifras de sodio en sangre y la excreción fraccional de sodio (EFNa) se consideraron como medidas de resultado. Resultados: Los 205 pacientes incluidos en el estudio se distribuyeron en tres grupos según el resultado inicial de la natremia. En 37 casos se detectó hiponatremia (18,04 %), en 133 niños isonatremia (64,87 %) y en 35 niños hipernatremia (17,07 %). Después de administrar soluciones hipotónicas encontramos en todos los grupos diferencia significativa entre el sodio sérico inicial y el final; en el grupo con hiponatremia el sodio subió y en los grupos con iso e hipernatremia el sodio descendió ligeramente. Se evidenció correlación significativa entre la EFNa y la evolución de la natremia (Na sérico inicial – Na sérico final). No se detectó ningún caso de hiponatremia posinfusión y tampoco se encontró correlación entre el agua libre administrada y la evolución de la natremia. Conclusiones: En lactantes con funcionamiento renal normal no se ha encontrado hiponatremia como resultado de la administración de sueros hiposalinos intravenosos, hallándose diferencias significativas en la EFNa que indican el ajuste renal de la natremia. Keywords: Gastroenteritis. Hyponatraemia. Hypotonic fluids. Palabras clave: Gastroenteritis. Hiponatremia. Sueros hipotónicos. Correspondence: Marciano Sánchez Bayle Sección de Pediatría. Hospital Niño Jesús. Menéndez Pelayo, 65. 28009 Madrid. (Spain). [email protected] [email protected] INTRODUCTION Acute gastroenteritis (AGE) is one of the most frequent medical pathologies in the first years of life and it can lead 477 originals to dehydration that requires the child’s hospitalisation and the subsequent use of parenteral rehydration solutions. An imbalance between the intake and loss of free water or serum sodium can occur in AGE which can cause hyponatraemia, in other words, a serum sodium level <135 mEq/l1. Ever since Holliday and Segar initiated a parenteral rehydration standard in 1957 that continues today, it is frequent to use hypotonic fluid in the intravenous correction of water deficit in children with AGE 2. Furthermore, in 1957, Schwartz published the first case of a metabolic disorder in which the anti-diuretic hormone (ADH) was released by non-physiological stimuli, which would cause the retention of electrolyte-free water followed by a high sodium concentration in the urine with resulting hyponatraemia3. When a loss of intravascular fluid occurs due to dehydration, ADH is released, which forces the kidneys to retain water even if suffering from hyponatraemia, since the signalling for volaemic compensation takes priority over the natraemia control mechanisms. Nausea, vomiting and dehydration make up the non-osmotic stimuli for ADH secretion and are present in AGE 4. Serious secondary effects from the use of hypotonic fluids or from perfusion rhythm were documented, since they can cause dilution hyponatraemia with the risk of neurological repercussions of variable severity5. At present, higher levels of NaCl in hydration solutions are recommended to prevent hyponatraemia, but there is the possibility that these recommendations are not appropriate in infants6. Most electrolyte imbalances occur in the hospital and among them, hyponatraemia is the most frequent. Children have a particularly high risk of secondary hyponatraemia and prognosis is worse than in later life. This study aims to determine whether the use of hypotonic fluids involves a risk for iatrogenic hyponatraemic in children hospitalised due to AGE and to analyse whether initial natraemia can predict the risk of developing iatrogenic hyponatraemia in our series. PATIENTS AND METHOD This is a prospective study involving 205 patients aged between 1 and 28 months, of which 23 were younger than 6 months. Patients were admitted with dehydration due to AGE and/or intractable vomiting in order to receive fluid therapy in the infant department of the Niño Jesus Children’s Hospital, Madrid, from January to December 2010. The reasons recorded for admittance and subsequent parenteral rehydration were the combination of mild or moderate dehydration and/or continuous vomiting, 478 Marciano Sánchez-Bayle et al. Fluid therapy and hyponatraemia as well as insufficient intake of oral liquid during stay in the emergency department. The initial degree of initial dehydration was estimated using standard clinical measurements, according to the Gorelick score7. 55 patients presented mild dehydration, and the remaining 155 patients were moderately dehydrated. 19 children were excluded from the study, the exclusion criteria being: nephropathy, heart disease, chronic diseases, hypothalamus-hypophysis pathology and also admittance to the intensive care unit due to the seriousness of the process. Informed consent was obtained and the hospital’s ethical committee approved the study. In order to determine whether baseline plasma sodium was a subsequent risk indicator for dilution hyponatraemia, response to intravenous fluids was analysed based on three groups of baseline natraemia: normonatraemia, hyponatraemia and hypernatraemia. Hyponatraemia was defined as a sodium serum level <135mmol/l; normonatraemia as 135-145mmol/l; and hypernatraemia >145mmol/l. A separate analysis of the results was carried out in accordance with the classification of hyponatraemia, isonatraemia or initial hypernatraemia. Urine and blood samples were taken to determine sodium levels and osmolality before starting fluid therapy and before beginning oral feeding and/or administering any oral liquid. The urine sample was taken as close to the blood sample as possible. Fractional sodium excretion represents the percentage of sodium filtered that is finally excreted and is calculated in all patients using the formula: sodium in urine x creatinine in blood x 100/sodium in blood x creatinine in urine8. Free water administered in ml / kg of weight and ml/hour was also analysed. The difference between the volume of fluid infused with saline solution and the volume of fluid infused with isotonic saline solution was calculated in order to administer the same amount of sodium chloride; all calculated in ml/hour divided by the child’s weight (kg)9. The solutions administered were 0.3 % glucosaline (0.3 % saline solution with 5 % glucose) in 198 cases and 0.2 % gluco-hyposaline (0.2 % saline solution with 5 % glucose) in the 7 remaining cases, all with initial hypernatraemia. Fifteen patients previously needed expansion with saline solution. Fluid infusion included baseline requirements in addition to estimated deficit. Administration of fluids and/or oral solids restarted when vomiting eased. Nefrologia 2014;34(4):477-82 Marciano Sánchez-Bayle et al. Fluid therapy and hyponatraemia The statistical analysis was carried out using SPSS 15.0 commercial software. Basic data was expressed in means and standard deviations for quantitative variables, and in numbers and percentage for qualitative variables. 95 % confidence intervals (95 % CI) were calculated. Comparisons between quantitative variables were made using the Mann-Whitney test after verifying that they were not adjusted to a normal distribution (KolmogorovSmirnov test). If distribution was normal, the Student’s t-test was applied. The Pearson correlation coefficients were calculated. Values of P<.05 were considered to be statistically significant. RESULTS 205 was the total number of patients admitted with a diagnosis of mild/moderate dehydration caused by AGE in 2010 and who were included in the study; 117 patients were boys (57.03 %) and the remainder, girls. The degree of dehydration was mild in 55 cases (26.82 %) and moderate in 150 (73.17 %). 198 patients received 0.3 % saline solution (0.3 % saline with 5 % glucose) and 7 patients, whose analysis showed baseline hypernatraemia, received 0.2 % gluco-hyposaline solution (0.2 % saline with 5 % glucose). Expansion with saline solution was previously required in 15 patients. The age range of the children was 1 to 28 months; average age was 11.52 months and standard deviation (SD) 5.77. Twenty-three patients (11.21 %) were younger than 6 months. Mean weight of the patients was 8.44kg, 1.85SD. Mean infused volume/kg/hour was 5.51, 1.3SD. The incidence of baseline hyponatraemia in these patients was 18.04 %. In the initial analysis, we separated the patients into three groups according to baseline natraemia: 37 hyponatraemic patients (18.04 %), 133 normonatraemic patients (64.87 %) and 35 hypernatraemic cases (17.07 %). Mean baseline glycaemia was 99.42mg/dl (18.61SD), with range 40-166mg/dl, and values <70mg/dl were found in 45 children (21.95 %). In the first group, after administering 0.3 % saline solution, serum sodium increased from 131.9mEq/l (2.07SD) to 135.6mEq/l (2.54SD). Serum sodium slowly reduced in the second group, without resulting in hyponatraemia, from 139.18 (2.9SD) to 137.92 (2.5SD); and likewise reduced in the third group from 150.17 (4.2SD) to 142.02mEq/l (4.3SD). There were no cases of hyponatraemia postinfusion. Blood and urine tests were performed after an average time of 12.34 hours (95 % CI 11.94-12.56) from the onset of fluid therapy. Nefrologia 2014;34(4):477-82 originals Table 1 shows the results of the biochemical measurements in blood at the time of diagnosis and at the end of treatment, before beginning oral feeding. Table 2 shows the evolution of natraemia in all the study’s patients, depending on whether or not they had initial hyponatraemia. An increase of serum sodium was observed in those patients with initial hyponatraemia and these patients had significantly lower fractional sodium excretion compared to those without initial hyponatraemia. Shown in table 3 are the analytical results obtained in blood and urine after beginning fluid therapy with hypotonic solutions and in accordance with baseline natraemia: hyponatraemia, isonatraemia and hypernatraemia. We found significant difference between baseline and final serum sodium in all groups: sodium increased in the group with hyponatraemia, and slightly decreased in the groups with isonatraemia and hypernatraemia. Table 1. Initial and final analysis (before starting oral feeding) Baseline M (SD) Final M (SD) Na (mEq/l) 141.2 (5.8) 137.4 (4.1) K (mEq/l) 4.2 (0.53) 3.9 (0.55) Cl (mEq/l) 108.7 (8.5) 107.6 (5.8) Urea (mg/dl) 38.4 (16.7) 18.5 (12.5) Creatinine (mg/dl) 0.47 (0.13) 0.36 (0.08) SD: standard deviation; M: mean. Table 2. Comparison of initial and final sodium of each group Hyponatraemia M (SD) No hyponatraemia M (SD) Baseline Na(mEq/l) 131.9 (2.07) 141.8 (5.4) Final Na (mEq/l) 135.6 (2.54) 138.9 (3.9)a EFNa 0.15 (0.27) 0.59 (0.71)a Free water 11.82 (3.88) 12.79 (10.8) a SD: standard deviation; EFNa: fractional sodium excretion; M: mean. Comparison of baseline and final sodium and EFNa between the hyponatraemia group and the remainder. a P<.0001. 479 Marciano Sánchez-Bayle et al. Fluid therapy and hyponatraemia originals Table 3. Fluid therapy according to natraemia Na < 135 M (SD) Na 135-145 M (SD) Na > 145 M (SD) Baseline Na (mEq/l) 131.9 (2.07) 139.18 (2.9) 150.17 (4.2) Final Na (mEq/l) 135.6 (2.54) 137.92 (2.5) 142.02 (4.3)d EFNa 0.15 (0.27) 0.58 (0.61)b 0.77 (0.55)c Free water 11.82 (3.88) 12.69 (5.8) 13.3 (6.8) Na/Creatinine Urinary 0.77 (0.45) 2.35 (2.5) 2.1 (2.8) a b SD: standard deviation; EFNa: fractional sodium excretion; M: mean. P=.012; bP=.009; cP=.023; dP<.0001. a The Pearson correlation coefficients between fractional sodium excretion and the analysed variables were: 0.413 with baseline sodium (P=.01), 0.808 with sodium evolution (P=.003) and there was no significance with infused free water (r = 0.028). DISCUSSION This study evaluates parenteral treatment with hypotonic saline solutions in mild and moderate dehydration of paediatric patients hospitalised with AGE and the possible link with the iatrogenic development of hyponatraemia, which was not proved in our case. Despite the recommendation and acceptance of solutions taken orally to rehydrate children with mild or moderate dehydration caused by AGE, it was observed that intravenous fluids were frequently used in developed countries10,11. Suitable tonicity of the solutions is a subject of controversy, without which a consensus on the type of solution for the most convenient maintenance in hospitalised children would be reached. At the time of assessing and discussing the results of the consulted literature, the studied paediatric pathologies should have been considered 12, since the baseline hydrosaline situation of the case of a child with AGE differs to that of a critical patient or that of a child who undergoes surgery. Hydroelectrolytic management in the infant has to be performed cautiously due to the immaturity of the renal function. Newborns have a high percentage of total body water, with a higher percentage of extracellular water and lower intracellular water percentage than adults. This situation changes progressively with age and the percentages of total, intracellular and extracellular water normalise around 6-12 months of life13. The newborn presents glomerular-tubular imbalance and a limited capacity of concentration and dilution of urine. The excreted sodium fraction is inversely proportional to gestational age 480 in the newborn and there is no aldosterone suppression due to sodium load, which would explain the small adaptation of the youngest infants to sodium excess14,15. In 2007, the National Patient Safety Foundation16 in the United States recommended changing parenteral saline solutions from 0.18 % to 0.45 % to prevent hyponatraemia in infancy. However, Coulthard17 warns about the risk of developing hypernatraemia with the previous standard and considers hypotonic solutions as more physiological at the time of replacing the losses. Halberthal et al. recommend the use of hypotonic solutions in patients with serum sodium >140mmol/l 18. Curiously, the publications by Moritz18, which group various studies on the subject from 2004 to 2011, indicate that the administration of hypotonic fluids is dangerous and anti-physiological19,20. Our results coincide with those presented in 2006 by Sánchez Bayle at al. 21 The incidence of hyponatraemia at the time of diagnosis was 18.04 % in our study and there were no cases of iatrogenic hyponatraemia. The high incidence of baseline hypoglycaemia in our patients leads us to think that the use of a glucose-free solution would aggravate baseline hypoglycaemia, with consequential risks. As regards fractional sodium excretion, our results show that it is significantly lower in children with baseline hyponatraemia, which seems to demonstrate that renal management of sodium is the essential physiological mechanism for regulating and correcting natraemia. Neville et al. 22,23 report an baseline hyponatraemia incidence of 36 %, they recommend the use of 0.9 % saline solution in the case of AGE and refer to the nonosmotic stimuli present in patients with AGE which could be involved in iatrogenic hyponatraemia. Holliday and Segar 24 did not consider that hospitalised patients were submitted to numerous non-osmotic stimuli for ADH secretion and considered that secondary hyponatraemia at the rehydration standard proposed by them in 1957 would Nefrologia 2014;34(4):477-82 Marciano Sánchez-Bayle et al. Fluid therapy and hyponatraemia be due to excessive administration of fluids. The results obtained by Hoor et al.9 in their study using a sample of 1586 children concluded that hyponatraemia was due to incorrect treatment in which more fluids were administered than necessary. It is important to remember that natraemia does not precisely reflect body sodium content and that rather than the reduction of serum sodium, it more precisely reflects the increase of total body water. True hyponatraemia is associated with serum hypo-osmolality; therefore it is necessary to understand plasma osmolality and also urine osmolality to determine whether there is deterioration in the capacity to excrete free water. However, Kannan et al.25 report 14.3 % iatrogenic hyponatraemia after administering 0.18 % saline solution, but patients with AGE were not included in their study. Armon et al.26 consider that using 0.9 % solutions would not be protective. Caramelo et al.27,28 do not find association between more hypotonic solutions and hyponatraemia in their study carried out on operated adult patients and they emphasise the importance of renal retention of water and the volume of fluid administered as a mechanism to consider in hyponatraemia. Other studies performed using critical patients or patients undergoing surgery have conflicting conclusions29-31. A limitation of our study is that it was undertaken in one centre and future studies on the subject should be recommended. As a conclusion and in light of the significant disparity in this field, we point out that it is not possible to accept the conclusion that hyponatraemia is generated with hyposaline maintenance solutions. Considering the high percentage of children with hypoglycaemia, the use of hypo-sodium solutions would protect against this hypoglycaemia, in addition to not inducing hyponatraemia in a healthy kidney. The monitoring of electrolytes before and during treatment is necessary. It is important to reconsider the frequent and in many cases, unnecessary use of parenteral pathway in dehydrated patients and those with acceptable oral tolerance and to remember that oral rehydration is key, since it is associated with less secondary effects and significantly reduces hospital stay. FUNDING The present study has not received any type of funding. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. Nefrologia 2014;34(4):477-82 originals REFERENCES 1. Chung CH, Zimmerman D. Hypernatremia and hyponatremia: current understanding and management. Clinical Pediatric Emergency Medicine 2009;10(4):272-8. 2. Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics 1957;19:823-32. 3. Schwartz WB, Bennet W, Curelop S, Bartter FC. A syndrome of renal sodium loss and hyponatremia probably resulting from inappropriate secrecion of antidiuretic hormone. Am J Med 1957;23:529-42. 4. Moritz ML, Ayus JC. Disorders of water metabolism in children: hyponatremia and hypernatremia. Pediatr Rev 2002;23(11):371-80. 5. Moritz ML. Hiponatremia de adquisición hospitalaria: ¿por qué siguen produciéndose muertes? Pediatrics (Ed Esp) 2004;57(5):256. 6. Bilkis M, Montero D, Vicente F, Cheistwer A. Hidratación endovenosa en la práctica clínica. Nuevos enfoques terapéuticos para la gastroenteritis aguda. Arch Argent Pediatr 2007;105(5):436-43. 7. Gorelick MH, Shaw KN, Murphy KO. Validity and reliability of clinical signs in the diagnosis of dehydration in children. Pediatrics 1997;99(5):E6. 8. Santos Rodríguez F, García Nieto V. Exploración basal de la función renal. En: García Nieto V, Santos Rodríguez F (eds.). Nefrología Pediátrica. Madrid: Aula Médica; 2000. pp. 3-14. 9. Hoorn EJ, Geary D, Robb M, Halperin ML, Bohn D. Hiponatremia aguda relacionada con la administración intravenosa de líquidos en niños hospitalizados: estudio de observación. Pediatrics (Ed Esp) 2004;57(5):267-73. 10.Gutiérrez Castrellón P, Polanco Allué I, Salazar Lindo E. Manejo de la gastroenteritis aguda en menores de 5 años: un enfoque basado en la evidencia. Guía de práctica clínica ibero-latinoamericana. An Pediatr (Barc) 2010;72(3):220.e1-220.e20. 11.Hartling L, Bellemare S, Wiebe N, Russell KF, Klassen TP, Craig W. Oral versus intravenous rehydration for treating dehydration due to gastroenteritis in children. Cochrane Database Syst Rev 2006;(3):CD004390. 12.Ruza Tarrío FJ. ¿Es el momento de cambiar el tipo de solución de mantenimiento intravenoso en los niños hospitalizados? Evid Pediatr 2007;3:1. 13. Haycock GB, Aperia A. Salt and the newborn kidney. Pediatr Nephrol 1991;5(1):65-70. 14. Colomba Norero V, Andrés Maturana P. Fisiología renal en el recién nacido. Rev Child Pediatr 1994;65(4):234-40. 15.Rodríguez-Soriano J. Maduración del riñón neonatal. Nefrología pediátrica. México: Mosby/Doyma; 1996. p. 348. 16.National Patient Safety Agency. Patient safety alert 22: reducing the risk of hyponatraemia when administering intravenous infusions to children. Available at: www.npsa.nhs.uk (accessed 21 Nov 2007). 17.Coulthard MG. Will changing maintenance intravenous fluid from 0,18% to 0,45% saline do more harm than good? Arch Dis Child 2008;93:335-40. 18.Halberthal M, Halperin ML, Bhon D. Acute hyponatraemia in children admitted to hospital: retrospective analysis of factors contributing to its development and resolution. BMJ 2001;322:780-2. 19.Moritz M, Ayus JC. Prevention of hospital-acquired hyponatremia: Do we have the answers? Pediatrics 2011;128(5):980-3. 20.Moritz M, Ayus JC. Hospital-acquired hyponatemia. Why are hy481 originals potonic parenteral fluids still being used? Nat Clin Pract Nephrol 2007;3(7):374-82. 21.Sánchez Bayle M, Alonso Ojembarrena A, Cano Fernández J. Intravenous rehydration of children with gastroenteritis: which solution is better? Arch Dis Child 2009;91(8):716. 22.Neville KA, Verge CF, O’Meara MW, Walter J. Valores elevados de hormona antidiurética e hiponatremia en niños con gastroenteritis. Pediatrics (Ed Esp) 2005;60(6):343-50. 23.Neville KA, Verge CF, Rosenberg AR, O’Meara MW, Walker JL. Isotonic is better than hypotonic saline for intravenous rehydration of children with gastroenteritis: a prospective randomised study. Arch Dis Child 2006;91:226-32. 24. Holliday MA, Segar WE, Friedman A. Reducing errors in fluid therapy. Pediatrics 2003;111(2):424-5. 25. Kannan L, Lodha R, Vivekanandhan S, Bagga A, Kabra SK, Kabra M. Intravenous fluid regimen and hyponatraemia among children: a randomized controlled trial. Pediatr Nephrol 2010;25(11):2303-9. 26. Armon K, Riordan A, Playfor S, Millman G, Khader A; Paediatric Marciano Sánchez-Bayle et al. Fluid therapy and hyponatraemia 27. 28. 29. 30. 31. Research Society. Hyponatraemia and hypokalaemia during intravenous fluid administration. Arch Dis Child 2008;93:285-7. Caramelo C, Tejedor A, Criado C, Alexandru S, Rivas S, Molina M, et al. Fluid therapy in surgical patients: composition and influences on the internal milieu. Nefrologia 2008;28(1):37-42. Alcázar Arroyo R. Post-surgery fluid therapy: the debate on tonicity is still open. Nefrologia 2008;28(1):25-7. Duke T, Molyneux M. Intravenous fluids for seriously ill children: time to reconsider. Lancet 2003;362:1320-3. Au AK, Ray PE, McBryde KD, Newman KD, Weinstein SL, Bell MJ. Incidence of postoperative hyponatremia and complications in critically-ill children treated with hypotonic and normotonic solutions. J Pediatr 2008;152(1):33-8. Álvarez Montañana P, Modesto i Alapont V, Pérez Ocón A, Ortega López P, López Prats JL, Toledo Parreño JD. The use of isotonic fluid as maintenance therapy prevents iatrogenic hyponatremia in pediatrics: a randomized, controlled open study. Pediatr Crit Care Med 2008;9(6):589-97. Sent to review: 29 Aug. 2013 | Accepted: 15 May. 2014 482 Nefrologia 2014;34(4):477-82 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society originals Soy protein and genistein improves renal antioxidant status in experimental nephrotic syndrome Mohammad H. Javanbakht1, Reza Sadria2, Mahmoud Djalali1, Hoda Derakhshanian1, Payam Hosseinzadeh1, Mahnaz Zarei1, Gholamreza Azizi3, Reza Sedaghat4, Abbas Mirshafiey2 1 Department of Cellular and Molecular Nutrition. School of Nutritional Sciences and Dietetics. Tehran University of Medical Sciences. Tehran (Iran); 2 Department of Pathobiology. School of Public Health. Tehran University of Medical Sciences. Tehran (Iran); 3 Alborz University of Medical Sciences. Imam Hassan Mojtaba Hospital. Karaj, Alborz (Iran);4 Department of Pathology. School of Medicine. Shahed University. Tehran (Iran) Nefrologia 2014;34(4):483-90 doi:10.3265/Nefrologia.pre2014.Jun.12051 ABSTRACT Background and objectives: Nephrotic syndrome is a chronic disease especially common in the childhood and adolescence. Reactive oxygen species (ROS) and free radicals have significant role in the pathogenesis of nephrotic syndrome. The aim of this study was to evaluate the effect of soy protein and genistein (main isoflavone of soybean) on renal antioxidant status of nephrotic rats. Methods: This study was done for 8 weeks on 40 adult male Sprague-Dawley rats divided into four groups of 10 rats each. Study groups included: 1-Control, 2-Nephrotic syndrome, 3-Nephrotic syndrome+soy protein diet and 4-Nephrotic syndrome+soy protein diet+genistein. Urine protein and urine creatinine were measured. After homogenization of kidney, total antioxidant capacities (TAC), activities of catalase enzyme, the concentration of malondialdehydes (MDA) and carbolynated proteins were determined spectrophotometrically. Pathological examination was done on kidneys with light microscope. Cell viability was evaluated with MTT assay on WEHI-164 fibro sarcoma cell line. The MMP2 enzyme activity was evaluated in different concentrations of genistein. Results: Total antioxidant capacity was significantly increased in soy genistein. Catalase activity was significantly increased in soy and soy genistein groups. Protein carbonyl and MDA were significantly lower in soy and soy genistein groups. The scores of pathological examination showed significant improvement in soy and soy genistein groups. Genistein decreased the proliferation of the WEHI-164 fibrosarcoma cell line. Conclusion: It seems that soy protein decreases kidney damages in nephrotic syndrome. Adding genistein to soy protein causes improvements in antioxidant status of kidney tissue. Genistein decreases proliferation of cell. La genisteína y la proteína de soja mejoran el estado antioxidante renal en el síndrome nefrótico experimental Keywords: Antioxidant. Genistein. Nephrotic Syndrome. Rat. Soy. Palabras clave: Antioxidante. Genisteína. Síndrome nefrótico. Rata. Soja. Correspondence: Abbas Mirshafiey Department of Pathobiology. School of Public Health. Tehran University of Medical Sciences. Poorsina Street. Enghelab Avenue. Tehran (Iran). [email protected] [email protected] RESUMEN Antecedentes y objetivos: El síndrome nefrótico es una enfermedad crónica especialmente común en la infancia y la adolescencia. Las especies reactivas del oxígeno (ERO) y los radicales libres desempeñan un papel importante en su patogénesis. El objetivo de este estudio es evaluar los efectos de la genisteína (principal isoflavona de la soja) y la proteína de soja en el estado antioxidante renal de ratas nefróticas. Métodos: Este estudio se llevó a cabo durante 8 semanas con 40 ratas Sprague-Dawley machos adultas, que fueron divididas en cuatro grupos de 10. Cada uno de los grupos de estudio incluía: 1 control, 2 con síndrome nefrótico, 3 con síndrome nefrótico más una dieta a base de proteína de soja y 4 con síndrome nefrótico más una dieta a base de proteína de soja más genisteína. Se midieron tanto los niveles de proteína como de creatinina en orina. Tras la homogenización del tejido renal, se calcularon mediante espectrofotometría la capacidad antioxidante total (CAT), la actividad de la enzima catalasa, la concentración de malondialdehídos (MDA) y las proteínas carboniladas. El examen patológico de los riñones se realizó con el microscopio óptico. Además, se evaluó la viabilidad celular con un ensayo de MTT de la línea celular de fibrosarcoma WEHI-164. También se evaluó la actividad de la enzima MMP2 con distintas concentraciones de genisteína. Resultados: La capacidad antioxidante total aumentó significativamente en las ratas que tenían una dieta de genisteína, al igual que la actividad de la catalasa en aquellas con una dieta de soja y genisteína. En cambio, los grupos carbonilo de las proteínas y los niveles de MDA fueron significativamente inferiores en los animales con una dieta de soja y de genisteína. El examen patológico reveló una mejora significativa en los grupos con dietas de soja y de genisteína. Asimismo, la genisteína disminuyó la proliferación de la línea celular de fibrosarcoma WEHI-164. Conclusión: Parece ser que la proteína de soja reduce los daños renales causados por el síndrome nefrótico. La adición de genisteína a la proteína de soja produce mejoras en el estado antioxidante del tejido renal. La genisteína disminuye la proliferación celular. INTRODUCTION Nephrotic syndrome is a chronic disease mostly in the childhood and adolescence.1 It is due to alterations in 483 originals Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant the penetrability of the glomerular barrier, resulting from the activities of proteases and a decline in the synthesis of the proteoglycans. 2 These malfunctions result in the emergence of a series of symptoms including severe proteinuria, hypoalbuminemia, hyperlipidemia and edema.3 Decreases of the glomerular blood flow and level of glomerular filtration rate (GFR) result from vasoconstrictor bioactive lipids (prostaglandin, thromboxane, plateletactivating factors (PAF)) and inhibition of nitric oxide activity.2,3 There are several evidences available concerning the roles of reactive oxygen species (ROS) and free radicals in the pathogenesis of nephrotic syndrome.3,4 The sources of ROS are the electron transport chain, oxidant enzymes, phagocytosis and auto-oxidation from epinephrine. 2,4 Free radicals have great contribution in the damages resulted in DNA, proteins, carbohydrates and lipids destruction.5 ROS results in lipid per-oxidation in the cellular and organelles membranes. It leads to loss of cell’s structure and capacity to transmit and produce energy, especially in the proximal tubules. Meanwhile, ROS are produced in nephritis by the immunity system, the infiltrated blood cells (polymorphonuclear, leukocytes, and monocytes), podocytes and mesangial matrix cells.2 There are various antioxidant defensive mechanisms for protecting the cells against the harmful effects of ROS and free radicals. Some of these defensive mechanisms are superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GR).6 In nephrotic syndrome, the balance between the oxidant and antioxidant is lost.3 Some studies showed the decreasing trend in the activities of the antioxidant enzymes and vitamins C, E, beta-carotene and total antioxidant capacity, while the MDA level increased.7 In order to generate the nephrotic syndrome experimental model in the rats, adriamycin and/or puromycin amino nucleoside may be used, while their metabolisms resulted cause formation of reactive oxygen species (ROS), followed by appearance of severe proteinuria and decreased kidney performance.8,9 The protective effects of some of compounds against the oxidative damages are associated to their capacity to increase the antioxidant enzymes expression. Lack of foodstuffs containing antioxidant or suppression of antioxidant enzymes worsens the kidney damages resulting from free radicals.10 Soybean with the same protein quality as animal proteins is considered the richest source of isoflavones. Its isoflavones are Genistein, Daidzein and Glystein. They have estrogenic effects, therefore they are called phytoestrogens. 11 It has been observed that foodstuffs containing soybean may have useful effects on the cardiovascular and renal diseases.12 Scientists believe that isoflavones, by their antioxidant nature, neutralize free radicals and decrease inflammatory reactions.13 There have been addressed several mechanisms concerning the effect of soybean on the renal diseases; however, they have attributed all the effect of soybean on kidney to its Genistein.10 In various studies, the roles of Genistein, as the major soybean isoflavone, have been studied in a variety of 484 cellular mechanisms, e.g. 1) Apoptosis induction; 2) Cellular differentiation; 3) Prevention of cellular reproduction; 4) Controlling cell cycle progression; 5) Antioxidant effect; 6) Repetitive effectiveness of the treatment-resistant anticancer drugs; 7) Angiogenesis controlling; 8) Inhibiting osteoclast; 9) Controlling cellular immunity activity and its extension; 10) Mast-cell sustainability and decreased inflammation.14 The purpose of this study is to examine the effects of Genistein as an isoflavone, together with the soybean protein, on the glomerulosclerosis induced by adriamycin, and also studying the potential cytotoxicity and preventive effects of Genistein on cellular proliferation and activity of matrix metalloproteinase (MMPs) on the WEHI-164 fibrosarcoma cell lines. MATERIALS AND METHODS This study was done on 40 adult male Sprague-Dawley rats. 12-15 weeks old rats weighing 300±50g were obtained from Iranian Pasteur Institute and housed under standard condition of the animal room (temperature 25±3 centigrade degrees, humidity 50%, 12-hour light and 12-hour darkness) with free access to food and water. Then, they were randomly divided into four groups, of 10 rats each. The study protocol was approved by ethic committee of Tehran University of Medical Sciences (TUMS) which conforms to the provisions of the Declaration of Helsinki. Study groups included 1. Control (C): no disease induction + chow diet. 2. Nephrotic Syndrome (NS): induction of disease + chow diet. 3. Nephrotic syndrome receiving soy diet (NS+S): induction of disease + soy protein diet + gavaged with carboxymethyle cellulose (CMC) as placebo. 4. Nephrotic syndrome receiving soy diet and genistein (NS+S+G): induction of disease + soy protein diet + gavaged with genistein diluted in CMC. Diets In order to provide soy protein diet, AIN-93M was followed and casein protein was replaced with the same amount of soy protein (soy protein as 14.1% of total energy). Due to the lack of sufficient amount of methionine, it was added to soy diet prohibiting methionine deficiency (Table 1)15. Disease induction and intervention protocol All animals obeyed their diet for 2 weeks (chow diet for control and NS groups and soy diet for soy and soy-genistein Nefrologia 2014;34(4):483-90 Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant Table 1. Ingredients of soy diet Ingredients (g/kg diet) Soy protein 140 Cornstarch 465 Sucrose 100 Cellulose 50 Soybean oil 40 Mineral mixture 35 Vitamin mixture 10 Dextrinized cornstarch 155 L-Cystine 1 Methionin 0.8 Choline bitartrate 2.5 Tert-Butylhydroquinone (mg) 8 groups). Then, the induction of nephrotic syndrome was done by the intravenous injection of single dose of 8mg/ kg Adriamycin (Adriablastina, Farmitalia, Milan, Italy) in all groups except control.8 The study continued for 6 other weeks with each group receiving its especial diet. NS+S+G group also gavaged with 40mg/kg/day genistein diluted in CMC, while NS+S rats received CMC alone. At the end, the kidneys were brought out, washed with PBS and the right one was transferred to formalin for pathology examination and the left to sterile test tubes. The left kidneys were kept in -80. Determination of the Kidney Performance Status Urine collections were done for each group. Urine protein was measured colorimetrically by Pyrogallol-red kit (cat no. 10-545 ZiestChem Diagnostics, Tehran Iran). Urine creatinine was measured based on the Jaffe method (Pars Azmoon Co. Tehran, Iran). originals The activities of catalase enzyme in supernatans were determined by the HegoAebi’s method.17 the concentration of malondialdehydes in supernatants were measured spectrophotometrically with the thiobarbituric acid.18 The carbolynated proteins in supernatants were determined spectrophotometrically based on the reaction of carbonyl group with 2,4 dinitrophenylhydrazine.19 Kidney histopathology The severity and extensiveness of the glomerular damages were assessed by pathological examination on tissue slices with optical microscope. The severity of glomerulosclerosis was evaluated by 8 parameters including hypercellularity, lobular pattern, polymorphonuclear (PMN) infiltration, atrophy of lumen, degenerative necrotic changes, hyaline cast in lumens, interstitial leukocyte infiltration and fibrosis. These parameters were categorized into scales ranging from 0 to 3 (0=negative, 1=mild, 2=average, 3=severe). Cytotoxicity Studies Cell Culture The WEHI-164 fibro sarcoma cell line obtained from Iran Pasteur Institute was cultured in the media containing L-Glutamine, 10% FBS, RPMI and 100Unit/mL Penicillin/ Streptomycin and incubated in 37ºC, saturated moisture and 5% CO2 pressure. Evaluation of the oxidative stress parameters Total antioxidant capacities (TAC) of the kidney tissues were measured in supernatants with 2-2- Azino- bis- (3Ethyl benzthiazoline-6-Sulfonic acid) (ABTS) method. 16 Proliferation assay Cell viability was evaluated with MTT assay. MTT colorimetric test is based on the activity of the mitochondria dehydrogenase enzyme of the living cells in reduction of the MTT salt to the formazan non-solvable crystals, which could not pass through the cells’ membrane. The concentration of formazan is proportional to the number of viable cells. 20 Some of the WEHI-164 fibro sarcoma cell line was cultured in 96-cell plates with 8x103 cells in a well (incubated for 4 hours under 37ºC). Genistein suspended in RPMI was added to each well in 0, 1, 5, 10, 20, 40 & 80μg/well, concentrations. The plate was then incubated for 48 hours in incubator (37ºC). The respective supernatant was extracted. Two hundreds microlitres of the MTT solution with 0.5mg/mL concentration in phenol red-free media was added to each well and incubated for another 2-4 hours. The supernatants were extracted and 200μL of DMSO was added to each plate as solvent of the formazan crystals (purple precipitation). The plate light absorption was read with 570nm wavelength and 630nm reference wavelength by ELISA reader machine. Nefrologia 2014;34(4):483-90 Kidney Tissue Homogenization The frozen left kidneys were homogenized in buffer (PH=7/4 0.05% NaN3, 25mM Tris-Hcl, 2mM PMSF, 2mM EDTA) by sonication. The sonication process was done in five minutes with six cycles. After being centrifuged, the supernatants were separated and transferred to -80˚C. 485 originals Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant Gelatinase Zymography The mentioned-above cell line was cultured in 24-cell plates with 4x10 4 cells in a well. They were incubated for 4 hours allowing the cells to adhere to the plate and reaching to proper density. Then various densities of Genistein (0-400μg/mL) was added to each well and incubated for 48 hours under 37ºC, saturated moisture and 5% Co2 pressure. Separating the supernatants, they were centrifuged to remove cellular debris and kept under -20ºC until performing Zymoanalysis. The MMP2 enzyme activity was evaluated based on the method described elsewhere.21 In brief, Genistein-containing supernatants were aliquoted and electrophorized with the SDS-PAGE gel containing 0.5mg/mL of A gelatin (Merk Germany) and the tris-borate as buffer for 3 hours (100V). Then, the gel was washed with X-100 triton two times to extract SDS and incubated for 24 hours in Tris-Hcl gelatinase activation buffer, PH=7.4 containing 10mM Cacl2. After that, the gel was immersed in Coomissie Brillient Blue-G-250 1% (1% in 25% methanol and 10% acetic acid solved in water) for two hours. MMP-2 activity resulted in gel proteolysis and generation of brilliant bands on the blue background. The activity of MMP-2 was measured by using the Alpha Ease FC densitometry (Alpha Innotech- Miami, USA) comparing width and density of the bands appeared on the gel. Statistical Analysis The data has been shown in Mean±SD. Statistical package for the social sciences (SPSS, version 20, Chicago, IL) was used for statistical analysis. Parametric data analysis was performed by analysis of variance (ANOVA) and Post hoc test by Tukey-HSD. While the non-parametric data were analyzed by Mannwhitney & Kruskalwallis Tests. The data was considered meaningful with P value less than 0.05. RESULTS The urine protein to creatinine ratio was not significantly different among four groups at the beginning of the study (P=0.16) (Table 2). At the end of the study, the urine protein to creatinine ratio showed statistically significant difference among four groups (P<0.001). The normal group had the urine protein to creatinine ratio significantly different from other three groups (P<0.001) (Tukey HSD test). Disease induced groups including patients, soy and soy genistein showed differences in the urine protein to creatinine ratio but it was not significant. The urine protein to creatinine ratio was obviously less than the patient group in soy and soy genistein groups. The urine protein to creatinine ratio in soy genistein group was even lesser than it in soy group. Figure 1 shows malondialdehyde, protein carbonyl, total antioxidant capacity (TAC) and catalase enzyme activity in the kidney tissue of animals. TAC was significantly different among four groups (P=0.008). In post hoc comparison, tukey HSD test showed significant difference between nephrotic rats vs. control (P=0.036) and soy genistein (P=0.011). The groups were significantly different in tissue catalase activity (P<0.001). In multiple comparisons, the NS group showed significant difference with control (P=0.045), soy (P=0.014), and soy genistein (P<0.001). The amount of protein carbonylated in kidney tissue was different between groups (P=0.001). The protein carbonylated in kidney tissue had significant difference between NS and control (P=0.01), NS and soy (P=0.003), NS and soy-genistein (P=0.001). Malondialdehyde in kidney tissue was significantly different among groups (P<0.001) (Figure 1). The amount of malondialdehyde in tissue was significantly different between NS and control (P<0.001), NS and soy (P=0.004), NS and soy-genistein (P=0.002). The effect of genistein on cellular proliferation As Figure 2 shows, the increase in the genistein concentration accompanies with decrease in proliferation of the WEHI-164 fibrosarcoma cell line, while the decreased growth has been quite obvious under 5-80μg/ well density. In addition, we observed obvious increase in MMP-2 activities at 10mg/mL concentration of genistein (Figures 3 and 4). This effect was not shown in higher concentrations. Table 2. Urine protein creatinine ratio in group at the beginning and the end of study Control NS NS+S NS+S+G P value Urine protein creatinine ratio (mg/mg) at the beginning 2.91±1.21 4±1.02 4.74 ± 2.32 3.51±2.27 0.16 Urine protein creatinine ratio (mg/mg) at the End 3.84±1.24 63.90±7.30 53.35 ± 14.62 51.28±16.67 <0.001 NS: Nephrotic syndrome; NS+S: Nephrotic syndrome with soy diet; NS+S+G: Nephrotic syndrome with soy diet and genistein. Data are expressed as mean±SD. Analysis of variance (ANOVA) and Post hoc test by Tukey-HSD were used to detect differences in between the groups. 486 Nefrologia 2014;34(4):483-90 Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant originals Malondialdehyde 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 70 60 50 40 30 20 10 0 nmol/mL g/dl Total antioxidant capacity Control NS+S NS+S+G NS Control NS+S NS+S+G Catalase Ku/mg pr nmol/mg Protein carbonyl 45 40 35 30 25 20 15 10 5 0 Control NS+S NS+S+G NS NS 9 8 7 6 5 4 3 2 1 0 Control NS+S NS+S+G NS Figure 1. Concentration of malodialdehyde and of protein carbonyl, total antioxidant capacity and catalase activity in kidney tissue of four groups. G: genistein; NS: nephrotic syndrome; S: soy. Nefrologia 2014;34(4):483-90 the score of degenerative-necrotic changes (P=0.022). The score for tubular atrophy was significantly different among three groups (P<0.001). Its score was significantly lower in soy-genistein group in comparison to NS group (P=0.001). The soy and NS groups were significantly different based Evaluation of cell proliferation % of number of cells Histopathological Findings Table 3 shows the histopathological findings in different parameters. We compared the parameters of only three groups (NS, NS+S and NS+S+G). Hypercellularity parameter was significantly different among three groups (P<0.001) (Figure 5). The score of hypercellularity in NS group was significantly higher than that of soy and soygenistein groups (P=0.022 and P=0.01, respectively). The score of hypercellularity was also significantly lower in soy soy-genistein group in comparison to soy group (P<0.001). The score of lobular pattern was significantly different among three groups (P<0.001). Scores were significantly lower in soy-genistein group in comparison to soy (P<0.001) and NS groups (P=0.001). The score of PMN infiltration was significantly different among groups (P<0.001). Score of PMN infiltration was significantly lower in soy-genistein group in comparison to soy (P<0.001) and NS groups (P=0.001). The score for degenerative-necrotic changes was significantly different among three groups (P=0.001). Its score was significantly lower in soy-genistein group in comparison to soy (P=0.012) and NS groups (P=0.001). The soy and NS groups were significantly different based on 120 100 80 60 40 20 0 0 12510 204080 Genistein concentration (mg/0,2mL [well]) Figure 2. WEHI-164 fibrosarcoma cell line proliferation in different concentrations of genistein. 487 Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant Relative expression of MMP-2 activity (%) originals 160 140 120 Figure 4. Bands MMP-2 of WEHI-164 fibrosarcoma cell line 100 in different concentrations of genistein. 80 The score for interstitial fibrosis was significantly different among three groups (P<0.001). Its score was significantly higher in NS group in comparison to soy (P<0.001) and soygenistein groups (P=0.001). 60 40 20 0 0 5 DISCUSSION This study showed adding genistein to soy protein can decrease histological deteriorations in nephrotic syndrome. Soy protein, with or without genistein, decreased tissue malondialdehyde in nephrotic rats. Soy protein increased catalase activity and diminished carbonylated protein of kidney tissue in nephrotic syndrome. These findings support the beneficial effects of soy protein in nephrotic status. The beneficial effects of soy could be associated to its copious isoflavone, genistein. Genistein makes improvements in nephrotic syndrome through its antioxidant effects. 10,11 Some findings support the pivotal role of oxidative stress in nephrotic syndrome. The imbalance between oxidant and antioxidant factors causes the glomerular damage in renal diseases. 3 The activities of antioxidant enzymes decrease in nephrotic syndrome. Hence, the peroxidation products increase in kidney diseases. Malodialdehyde and carbonylated proteins are produced through peroxidation processes. 10 25 50 100 200 400 Genistein concentration (mg/mL) Figure 3. MMP-2 activity of WEHI-164 fibrosarcoma cell line in different concentrations of genistein. on the score of tubular atrophy (P=0.002). The score for hyaline cast was significantly different among three groups (P<0.001). Its score was significantly lower in soy-genistein group in comparison to soy (P<0.001) and NS groups (P=0.001). The soy and NS groups were significantly different based on the score of hyaline cast (P=0.016). The score for leukocytes infiltration in interstitial was significantly different among three groups (P=0.001). Its score was significantly lower in soy-genistein group in comparison to soy (P=0.021) and NS groups (P=0.001). The soy and NS groups were significantly different based on the score of leukocytes infiltration in interstitial (P=0.007). Table 3. Score of microscopic findings of kidney histology in various groups Control NS NS+S NS+S+G P value Hypercellularity 0 1.41±0.13 0.97±0.02 0.31±0.10 < 0.001 Lobularity pattern 0 1±0 0.92±0.05 0.06±0.04 < 0.001 PMN infiltration 0 1±0 0.97±0.02 0.21±0.05 < 0.001 Degenerative-necrotic changes 0 2.08±0.36 1.62±0.14 0 0.001 Atrophy of tubules 0 1±0.12 0.1±0.10 0 < 0.001 Hyaline cast 0 2.20±0.25 0.62±0.16 0.28±0.11 < 0.001 Leukocytes infiltration 0 1.66±0.24 0.75±0.13 0.34±0.09 0.001 Interstitial tubules fibrosis 0 0.83±0.10 0 0.06±0.06 < 0.001 NS: Nephrotic syndrome; NS+S: Nephrotic syndrome with soy diet; NS+S+G: Nephrotic syndrome with soy diet and genistein; PMN: polymorphonuclear. Data are expressed as mean±SD. Mannwhitney & Kruskalwallis Tests were used to detect differences in between the groups. 488 Nefrologia 2014;34(4):483-90 Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant Figure 5. Representative light microscopic view of histopathological slides of kidney in different groups. C: control; G: genistein; NS: nephrotic syndrome; S: soy. Previous studies showed that diets containing soy could decrease proteinuria in comparison to casein protein diets.10,13 In the process of nephrotic syndrome, serum albumin is lost through kidneys. Serum albumin functions as a major antioxidant in serum, hence albumin loss causes oxidative damage. In the case of albumin loss, MDA as a product of oxidative damage increases.3 Isoflavones mainly genistein restrict inflammation with their antioxidative, anti inflammatory and anti necrotic characteristics.13 The anti inflammatory effect of genistein is through inhibition of cyclooxigenase expression and myeloperoxidase activity. 22 Genistein decreases lipid peroxidation and serum lipids.23 Oxidative stress induces NFkB and inflammatory cytokines expressions.24 Isoflavones reacts with free radicals and neutralizes their effects.13 It seems isoflavones decrease renal damage through reacting with hydrochloric acid and peroxynitrate.10 More studies are needed to analyze the angiotensin-II receptors expression, TGF-β, NF-κB and strogen receptor beta to elucidate the possible contribution of these mechanisms to the renoprotective effect of genistein. The lack of these data is one of our limitations in this study. In our study, urine protein creatinine ratio was slightly lower in soy-genistein group than soy group, but this difference was insignificant. It seems we would observe significant difference in case of prolongation of the study. This observation supports the notion that the effects of soy are mainly due to its isoflavone, genistein.10,13 This study showed that adding genistein to soy protein enhances antioxidative status of kidney tissue, albeit insignificant. Some studies on the histopathology of nephrotic syndrome showed that soy diet in comparison to casein diet causes improvement in sclerotic and fibrotic sequels.13 Another research showed mesangeal and segmental proliferation with matrix expansion, capillary blockade, fibrosis with adhesion between glomerular coils and Bowman’s capsule, also mononuclear cells infiltration Nefrologia 2014;34(4):483-90 originals in interstitial space in case of receiving casein diet. But glomerular damage and fibrosis were less in rats receiving soy protein.10 A research showed that soy replaced in animal protein improved glomerular filtration rate and glomerular hypertension. It also decreased the incidence of diabetic nephropathy.25 In the current study, adding genistein to soy protein caused profound improvement in histopathology of kidney. The improvement was so impressive that soygenistein group resembled to normal group. Researches on the role of genistein in proliferation of malignant cell line showed that genistein induces apoptosis and suppression of cell proliferation through P53 pathway.26 Some researches supported the role of genistein in cell cycle inhibition specially breast and prostate cancer cell lines which are in consistent to our results on fibrosarcoma cell line WEHI-164.27 Another study on prostate cancer cell line showed inhibitory role of genistein on the activity of MMP-2 enzyme.28 Matrix metalloproteinases are inactive.29 Some factors like cancer cell lines, cytokines and inflammatory factors disturb their activity and balance.30 It is concluded from the results of current study that soy protein diet causes impressive changes in oxidative status markers and histopathological aspects of nephrotic syndrome. This study showed that adding genistein as an isoflavone to soy protein caused a greater improvement in this disease. We can conclude that the effects of soybean on nephrotic syndrome would be attributed to its isoflavone genistein. Acknowledgments This study was supported by undersecretary of research in Tehran University of Medical Sciences (the grant number of 15438). We honestly appreciate Karen pharma & food supplement company (Tehran, Iran) for the donation of some food components. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. REFERENCES 1. Bagga A, Mantan M. Nephrotic syndrome in children. Indian J Med Res 2005;122:13-28. 2. Palmieri B, Sblendorio V. Oxidative stress detection: what for? Eur Rev Med Pharmacol Sci 2007;11:27-54. 3. Ghodake S, Suryakar A, Ankush R, Katkam R, Shaikh K, Katta A. Role of free radicals and antioxidant status in childhood nephrotic syndrome. Indian J Nephrol 2011;21:37-40. 4. Machlin LJ, Bendich A. Free radical tissue damage: protective role of antioxidant nutrients. FASEB J 1987;1:441-5. 489 originals Mohammad H. Javanbakht et al. Soy-genistein improves renal antioxidant 5. Ahmad SM. Oxidative stress and antioxidant defenses in biology. New York; London: Chapman & Hall; 1995. 6. Lieberman MA, Marks A, Peet A. Marks’ basic medical biochemistry. LWW; 2012. 7. Mathew JL, Kabi BC, Rath B. Anti-oxidant vitamins and steroid responsive nephrotic syndrome in Indian children. J Paediatr Child Health 2002;38:450-37. 8. Razavi A, Nouri HR, Mehrabian F, Mirshafiey A. Treatment of experimental nephrotic syndrome with artesunate. Int J Toxicol 2007;26:373-80. 9. Mirshafiey A, Rehm BHA, Sahmani AA, Naji A, Razavi A. M-2000, as a new anti-inflammatory molecule in treatment of experimental nephrosis. Immunopharmacol Immunotoxicol 2004;26:611-9. 10. Pedraza-Chaverri J, Barrera D, Hernandez-Pando R, Medina-Campos ON, Cruz C, Murguia F, et al. Soy protein diet ameliorates renal nitrotyrosine formation and chronic nephropathy induced by puromycin aminonucleoside. Life Sci 2004;74:987-99. 11. Yousef MI, Kamel KI, Esmail AM, Baghdadi HH. Antioxidant activities and lipid lowering effects of isoflavone in male rabbits. Food Chem Toxicol 2004;42:1497-503. 12. Martínez RM, Giménez I, Lou JM, Mayoral JA, Alda JO. Soy isoflavonoids exhibit in vitro biological activities of loop diuretics. Am J Clin Nutr 1998;68:1354S-1357S. 13. Tovar AR, Murguia F, Cruz C, Hernández-Pando R, Aguilar-Salinas CA, Pedraza-Chaverri J, et al. A soy protein diet alters hepatic lipid metabolism gene expression and reduces serum lipids and renal fibrogenic cytokines in rats with chronic nephrotic syndrome. J Nutr 2002;132:2562-9. 14. Polkowski K, Mazurek AP. Biological properties of genistein. A review of in vitro and in vivo data. Acta Pol Pharm 2000;57:135-55. 15. Reeves PG. Components of the AIN-93 diets as improvements in the AIN-76A diet. J Nutr 1997;127:838S-41S. 16. Erel O. A novel automated direct measurement method for total antioxidant capacity using a new generation, more stable ABTS radical cation. Clin Biochem 2004;37:277-85. 17. Aebi H. Catalase in vitro. Methods Enzymol 1984;105:121-6. 18. Richard M, Portal B, Meo J, Coudray C, Hadjian A, Favier A. Malondialdehyde kit evaluated for determining plasma and lipoprotein fractions that react with thiobarbituric acid. Clin Chem 1992;38:704-9. 19. Castegna A, Drake J, Pocernich C, Butterfield DA. Protein carbonyl levels-an assessment of protein oxidation. Methods in Biological Oxidative Stress 2003;3:161-8. 20. M osmann T. Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods 1983;65:55-63. 21. Khorramizadeh MR, Aalizadeh N, Pezeshki M, Ghahary A, Zeraati H, Berahmeh A, et al. Determination of gelatinase A using a modified indirect hemagglutination assay in human prostate cancer screening and assessment of its correlation with prostate-specific antigen parameters. Int J Urol 2005;12:637-43. 22. Seibel J, Molzberger AF, Hertrampf T, Laudenbach-Leschowski U, Diel P. Oral treatment with genistein reduces the expression of molecular and biochemical markers of inflammation in a rat model of chronic TNBS-induced colitis. Eur J Nutr 2009;48:21320. 23. Velasquez MT, Bhathena SJ. Dietary phytoestrogens: a possible role in renal disease protection. Am J Kidney Dis 2001;37:1056-68. 24. Dozor AJ. The role of oxidative stress in the pathogenesis and treatment of asthma. Ann N Y Acad Sci 2010;1203:133-7. 25.Anderson JW. Beneficial effects of soy protein consumption for renal function. Asia Pac J Clin Nutr 2008;17 Suppl 1:324-8. 26. Lian F, Li Y, Bhuiyan M, Sarkar FH. p53-independent apoptosis induced by genistein in lung cancer cells. Nutr Cancer 1999;33:125-31. 27. Banerjee S, Li Y, Wang Z, Sarkar FH. Multi-targeted therapy of cancer by genistein. Cancer Lett 2008;269:226-42. 28. Huang X, Chen S, Xu L, Liu Y, Deb DK, Platanias LC, et al. Genistein inhibits p38 map kinase activation, matrix metalloproteinase type 2, and cell invasion in human prostate epithelial cells. Cancer Res 2005;65:3470-8. 29. Nagase H, Woessner Jr JF. Matrix metalloproteinases. J Biol Chem 1999;274:21491-4. 30. Leppert D, Waubant E, Galardy R, Bunnett NW, Hauser SL. T cell gelatinases mediate basement membrane transmigration in vitro. J Immunol 1995;154:4379-89. Sent to review: 2 Apr. 2013 | Accepted: 3 Jun. 2014 490 Nefrologia 2014;34(4):483-90 short original http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society Hidden sources of phosphorus: presence of phosphorus-containing additives in processed foods Luis M. Lou-Arnal1, Laura Arnaudas-Casanova1, Alberto Caverni-Muñoz2, Antonio Vercet-Tormo3, Rocío Caramelo-Gutiérrez1, Paula Munguía-Navarro1, Belén Campos-Gutiérrez4, Mercedes García-Mena5, Belén Moragrera5, Rosario Moreno-López6, Sara Bielsa-Gracia7, Marta Cuberes-Izquierdo8, Grupo de Investigación ERC Aragón* *Instituto Aragonés de Ciencias de la Salud. Zaragoza (Spain); 1 Servicio de Nefrología. Hospital Universitario Miguel Servet. Zaragoza; 2 Servicio de Nutrición y Dietética. Alcer Ebro. Zaragoza (Spain); 3 Departamento de Tecnología de los Alimentos. Facultad de las Ciencias de la Salud y del Deporte. Zaragoza (Spain); 4 Servicio de Nefrología. Hospital de Alcañiz. Teruel (Spain); 5 Servicio de Nefrología. Hospital San Juan de Dios. Zaragoza (Spain); 6 Servicio de Nefrología. Hospital Militar de la Defensa. Zaragoza (Spain); 7 Servicio de Nefrología. Hospital Obispo Polanco. Teruel (Spain); 8 Servicio de Nefrología. Hospital de Tudela. Navarra (Spain) Nefrologia 2014;34(4):498-506 doi:10.3265/Nefrologia.pre2014.Apr.12406 ABSTRACT Introduction and objectives: An increased consumption of processed foods that include phosphorus-containing additives has led us to propose the following working hypothesis: using phosphate-rich additives that can be easily absorbed in processed foods involves a significant increase in phosphorus in the diet, which may be considered as hidden phosphorus since it is not registered in the food composition tables. Materials and method: The quantity of phosphorus contained in 118 processed products was determined by spectrophotometry and the results were contrasted with the food composition tables of the Higher Education Centre of Nutrition and Diet, those of Morandeira and those of the BEDCA (Spanish Food Composition Database) Network. Results: Food processing frequently involves the use of phosphoric additives. Correspondence: Luis M. Lou Arnal Servicio de Nefrología. Hospital Universitario Miguel Servet. Zaragoza. (Spain). [email protected] [email protected] The products whose label contains these additives have a higher phosphorus content and a higher phosphorus/protein ratio. We observed a discrepancy with the food composition tables in terms of the amount of phosphorus determined in a sizeable proportion of the products. The phosphorus content of prepared refrigerated foods hardly appears in the tables. Conclusions: Product labels provide little information on phosphorus content. We observed a discrepancy in phosphorus content in certain foods with respect to the food composition tables. We should educate our patients on reviewing the additives on the labels and on the limitation of processed foods. There must be health policy actions to deal with the problem: companies should analyse the phosphorus content of their products, display the correct information on their labels and incorporate it into the food composition tables. Incentives could be established to prepare food with a low phosphorus content and alternatives to phosphorus-containing additives. Keywords: Food additives. Phosphorus intake. Phosphorus-protein ratio. Hyperphosphatemia. Food analysis. Chronic kidney disease. Phosphorus absortion. Food labelling. Food composition. * Group members: Hospital Universitario Miguel Servet: Dr. Luis Miguel Lou Arnal, Dr. Álex Gutiérrez Dalmau, Dr. Jesús Pérez y Pérez, Dr. Alejandro Sanz París, Dr. Laura Arnaudas Casanova, Dr. Laura Sahdalá Santana, Dr. Beatriz Lardiés Sánchez, DUE Gloria Millán Asín, DUE Rosa Isabel Muñoz, DUE Gloria Pérez Sierra; Hospital Clínico Universitario Lozano Blesa: Dr. Rafael Álvarez Lipe, Dr. José Antonio Gimeno Orna, DUE Mercedes Marcén Letosa, DUE Blanca Aznar Arribas, DUE Inma Serrano; Hospital San Juan de Dios: Dr. Mercedes García Mena, Dr. Marta Luzón Alonso, Dr. Belén Moragrega, Dr. Elena Castillón, DUE María Duran Andía, DUE María Carmen Sancho Alcázar, DUE Cristina Callizo Pequerul; Hospital Militar de la Defensa: Dr. Rosario Moreno López, Dr. Raquel Abadía del Olmo; Hospital Comarcal de Alcañiz: Dr. Olga Gracia García, Dr. Belén Campos Gutiérrez, DUE Miriam Sorribas Marts; Hospital Obispo Polanco de Teruel: Dr. Sara Bielsa Gracia; Hospital de Calatayud Ernest Lluch: Dr. M.ª José Aladren Regidor; Hospital de Tudela: Dr. Marta Cuberes Izquierdo; Hospital San Jorge: Dr. Rafael Virto Ruiz, Dr. Carlos Bergua Amores; Alcer Ebro: Sr. Alberto Caverni Muñoz, Sra. Cristina Calles Merino, Sra. Carmen Jiménez Cortes, Dr. Hana Maher Berlín. 498 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD Fuentes ocultas de fósforo: presencia de aditivos con contenido en fósforo en los alimentos procesados RESUMEN Introducción y objetivos: El incremento del consumo de alimentos procesados que incluyen aditivos con fósforo nos lleva a plantearnos la siguiente hipótesis de trabajo: la utilización de aditivos ricos en fosfatos fácilmente absorbibles en los alimentos procesados supone un incremento significativo del fósforo contenido en la dieta, que puede considerarse como fósforo oculto al no quedar registrado en las tablas de composición de alimentos. Material y método: Se determina la cantidad de fósforo contenido en 118 productos procesados mediante espectrofotometría. Se contrastan los resultados con las tablas de composición de alimentos del Centro de Enseñanza Superior de Nutrición y Dietética, de Morandeira y de la Red BEDCA. Resultados: El procesamiento de los alimentos con frecuencia implica el uso de aditivos fosfóricos. Los productos en cuya etiqueta figuran estos aditivos presentan un mayor contenido en fósforo y una mayor ratio fósforo/proteínas. Apreciamos discordancia con las tablas de composición de alimentos en la cantidad de fósforo determinada en una parte importante de los productos. El contenido en fósforo de alimentos refrigeradoselaborados apenas figura en las tablas. Conclusiones: El etiquetado de los productos ofrece información escasa sobre el contenido en fósforo. Apreciamos disparidad de contenido de fósforo en determinados alimentos respecto a las tablas de composición de alimentos. Deberíamos formar a nuestros pacientes en la revisión de los aditivos en las etiquetas y en la limitación de los alimentos procesados. Una aproximación al problema debe incluir actuaciones de política sanitaria: las empresas deberían analizar el contenido en fósforo de sus productos, reflejar este dato en el etiquetado e incorporarlo en las tablas de composición de alimentos. Podrían establecerse incentivos para elaborar alimentos con contenido bajo en fósforo y alternativas a los aditivos que contienen fósforo. Palabras clave: Aditivos alimentarios. Ingesta de fósforo, Cociente fósforo/proteínas. Hiperfosforemia. Encuesta dietética. Enfermedad renal crónica. Absorción de fósforo. Etiquetado de los alimentos. Composición de los alimentos. INTRODUCTION High levels of phosphorus are related to the development of arteriosclerosis and bone disease in patients with chronic kidney disease (CKD)1. Phosphorus intake is also a public health problem given its impact on cardiovascular risk in the general population (“new cholesterol”)2-4. The wide and growing use of these additives5, in relatively high quantities6, without clear regulations in the labelling7,8 and usually without their inclusion in the food composition tables means that there is a high phosphorus contribution, which we can consider to be “hidden phosphorus”9. The dietary recommendations in CKD aim to obtain an adequate protein contribution with reduced phosphorus intake, which is a difficult balance to achieve. Additives provide phosphorus without protein, which is something we should consider in the dietary education of our patients. However, it is difficult to know the real phosphorus contribution in the Nefrologia 2014;34(4):498-506 short original diet, given the limited information on the product labels and the few and confusing data in the food composition tables10. The main objective of this study was to provide information about the real phosphorus content determined by spectrophotometry in an extensive group of 118 natural products and with different degrees of processing. As secondary objectives, we aimed to indicate the differences and contradictions with respect to the different food composition tables and make nephrologists, dieticians and nursing staff aware of this barrier in dietary education, in order to facilitate practical training for our patients. MATERIAL AND METHOD Study design: descriptive cross-sectional study with analysis of food product components. We received financing of the Aragón Health Sciences Institute over two years to determine phosphorus and protein in 118 fresh products with different degrees of processing. In the first 52 products we analysed three different batches. After verifying the reproducibility of the phosphorus measurements, we acquired two batches of the following 66 products analysed and carried out a third test when the values were conflicting (coefficient of variation [CV] [standard deviation (SD/average value] ≥10%). The detailed methodology of the study is displayed in a previous publication10. Total phosphorus was determined using molecular absorption spectrophotometry and total protein content was determined by the Kjeldahl method. These tests were carried out in the Aragón Food Technology and Research Centre. The averages of the tests were considered to be phosphorus measured. Protein content, which was more standardised, was only measured in the first batch of each product. Expression of results Phosphorus content was expressed in mg/100g of the product and the protein content was expressed in g/100g of the product. We added the calculation of the phosphorus [mg]protein [g] ratio due to its relevance in our patients11. The Kidney Disease Outcomes Quality Initiative guidelines recommend a dietary ratio of 10-12mg/g. We reviewed the information on phosphorus and protein content of the different food processed in the Moreiras food composition table12, that of the Nutrition and Diet Higher Education Centre13 and that of the BEDCA (Spanish Food Composition Database) of the Ministry of Science and Innovation, Spanish Food Safety and Nutrition Agency14. 499 short original Statistical analysis The description of quantitative variables was carried out with their mean ± SD and the qualitative variables with the distribution of frequencies. We carried out a phosphorus content repeatability study in various foods, with two or three repetitions for each sample. We calculated the mean, SD, and the CV (CV=SD/mean) expressed as a % and the repeatability interval (r=SDx2.8) for each set of repeated tests of the same sample. Subsequently, we calculated the means of all the previous tests in all the samples. We considered CV values between phosphorus tests in the same sample <10% to be acceptable. We considered P values <.05 to be statistically significant. We analysed the data with the SPSS version 15.0 software. RESULTS The results obtained in our tests are shown in Tables 1, 2 and 3. For a comparison, the data of the food composition tables are expressed in Table 4. Of the 118 products analysed, 50 (43.2%) contained phosphorus additives, according to the labels. The mean phosphorus value in the total samples was 162.1 (range 21.4-790.3) mg/100g, the mean SD was 9.93mg/100g, the mean CV was 6.7% and the mean repeatability interval (r) was 29.3mg/100g (this implies that 95% of the time, a new test, repeated again, did not differ by more than 29.3mg/dl from the mean of the previous tests). In values below the median, the mean of the phosphorus tests in the total sample was 120.3 (range 21.4-160.6) mg/100g, the mean of the SD was 8.7mg/100g, the mean of the CV was 7.9% and the mean repeatability interval (r) was 24.6mg/100g. In values above the median, the mean phosphorus test in the total sample was 205.3 (range 161.2-790.3) mg/100g, the mean SD was 10.3mg/100g, the CV mean was 5.4% and the mean repeatability interval (r) was 28.38mg/100g. The CV was significantly lower (5.3% vs. 7.9%; P=.016) in products with values above the median phosphorus content. There were no significant differences in the r value. In dairy products, the high phosphorus content is known, which increases in processed milk. Soy milk contributes half the phosphorus with a similar amount of proteins, and as such, it may be used in some patients, although we must bear in mind the problem of its palatability. Cheeses for melting and grating have phosphorus-containing additives in the form of melting salts. It must be noted that in fresh cheeses such as Burgos, the most tolerated in the dietary recommendations for our patients, we detected a high phosphorus-protein ratio in the six samples taken in two products (between 18.9 and 20.4mg/g), which is much higher than that displayed in two of the tables (13.7mg/g). Overall, the products without phosphorus additives have a phosphorus-protein ratio of 500 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD 10.2mg/g and those that contain these additives have a ratio of 15.3mg/g. Within cereals, simple products, such as Marie biscuits or white bread have a reasonable phosphorus-protein ratio of between 11.7 and 12.1mg/100g. Different brands of sliced bread may or may not include phosphorus additives, with a 23% increase in phosphorus content in those that contain them. “Spongy” products, such as cupcakes, or sobao cakes have a high phosphorus content, since their dough requires phosphoruscontaining additives, while products such as croissants reduce the phosphorus quantity since they do not include these additives. Products without phosphorus-containing additives have a phosphorus-protein ratio of 11.4mg/g and those that contain these additives have a ratio of 25.7mg/g. The tables display contradictory values for Marie biscuits, sobao cakes, croissants and chocolate cookies. The phosphorus-protein ratio in sausages decreases as the quality of the products increases, since they require fewer preservatives and flavouring. Specific products such as cooked ham, which do display the absence of phosphates on their labels effectively have a significant reduction in phosphorus content, of around 33%. Products that we may recommend to our patients, such as cold meats that are low in fat and salt, may have phosphorus-containing additives to give them texture and taste. Products without phosphorus-containing additives have a phosphorus-protein ratio of 10.2mg/g and those that contain these additives have a ratio of 15.5mg/g. The tables do not provide information about products without phosphates, and some low-phosphorus values in smoked and chopped bacon, chorizo and fuet salami are surprising, as well as contradictory data for chorizo, cooked ham and Bologna sausage. The results for meat products and fish were reported in a previous study10. In summary, we can say that the phosphorus-protein ratio is higher in processed meat products (15.83mg/g) than in breaded products (11.04mg/g) and frozen products (10.5mg/g), and is lower in fresh (8.41mg/g) and refrigerated meat products (8.78mg/g). Fresh white fish has a phosphorus-protein ratio of 8.58g/g while in frozen white fish, it increases by 22% (10.3mg/g) and in breaded white fish, by 46% (12.54mg/g). The information in the tables is poor and confusing, without reference to the brands analysed. We should highlight the reasonable phosphorus content in oily fish such as fresh salmon, frozen salmon and frozen swordfish (between 10.29 and 11.92mg/g), data that coincide with the table values for salmon (phosphorus-protein ratio between 12 and 12.9mg/g), although there are conflicting values for swordfish (phosphorus-protein ratio of 29.8mg/g in the Moreiras table). The wide diversity of refrigerated-prepared foods makes a systemic evaluation difficult. Their phosphorus content hardly appears in the tables, and the information is conflicting and Nefrologia 2014;34(4):498-506 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD short original Table 1. Results of the phosphorus and protein composition of foods and the phosphorus-protein ratio according to the tests by the Aragón Agri-Food Research Centre. Dairy products, cereals and cold meats Phosphorus mg/100 CITA Protein mg/100 CITA CITA phosphorusprotein ratio Phosphoruscontaining additive on the label Dairy products Hacendado whole milk Hacendado whole milk with calcium Yo soy milk Danone natural yogurt Actimel prebiotic yogurt Danet custard Burgos fresh cheese Hacendado own label fresh cheese Hochland cheese slices Entrepinares grating cheese 83.2±7 105±5 43.6±4 85.7±4 65.7±4 104.7±9 216.7±16 200.2±19 790.3±7 447.2±6 3.2 3.8 3.6 3.2 2.8 3.5 10.6 10.6 14 21 26 27.3 12.1 26.8 23.5 29.6 20.4 18.9 56.5 21.3 No E451 No No No E450 No No E452 E341 Cereals Hacendado Marie biscuits White bread Bimbo sliced white bread Hacendado sliced white bread Bella Easo non-iced fairy cakes Martínez Sobao cake Bella Easo croissants Doughnuts Bimbo “Tigretón” Swiss roll Mcennedy chocolate cookies 81.3±5 98.2±5 119.5±11 97.1±1 181.1±18 147±8 90.2±1 85.7±1 102.3±8 221.7±12 6.7 8.4 9.5 8.7 4.8 5.3 8.6 5.8 4 7.2 12.1 11.7 12.5 11.2 37.8 27.8 10.5 16.5 29.2 30.8 No No E341 No E450 E450 No E341 E450 E451 Cold meats Campofrío smoked bacon Eroski chopped pork Carrefour extra chorizo Valle Alagón extra Iberian chorizo Los Alcores extra fuet salami Campofrío cooked ham Casa Tarradellas extra cooked ham Bonatur Argal cooked ham without phosphates Carrefour cooked ham without phosphates Valle Alagón fattened Iberian ham loin Los Alcores cured Longaniza sausage Carrefour Bologna sausage Bonnatur Argal turkey breast El Pozo fat-free and salt-free turkey breast Juán Luna extra salchichón sausage Monter Hacendado extra salchichón sausage Iglesias Iberian salchichón sausage, Salamanca 250.1±2 216.3±18 228.2±12 245.4±19 320.8±26 258.1±14 270.8±1 187.4±14 172.4±7 268.1±23 275.9±21 172.3±37 231.2±19 263.4±9 228.5±63 273.4±38 225.9±18 13.1 9.85 21.3 26.2 28.1 19.2 19 20.1 19 30.6 30.1 14.4 16.6 14.6 16 21.4 26.3 19.1 22 10.7 9.4 11.4 13.4 14.2 9.3 9.1 7.33 9.2 11.9 13.9 18 14.3 12.8 8.6 E451 E451 E450 No No No No No No No No E451 E451 E451 E450-E451 E450-E451 No CITA (Agri-Food Technology and Research Centre): phosphorus values by spectophotometry and protein values by the Kjeldahl method tested in the Aragón Agri-Food Research Centre. Nefrologia 2014;34(4):498-506 501 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD short original Table 2. Results of the phosphorus and protein composition of foods and the phosphorus-protein ratio according to the tests by the Aragón Agri-Food Research Centre. Fresh, refrigerated, frozen, breaded and processed meats. Phosphorus mg/100 CITA Protein mg/100 CITA CITA phosphorusprotein ratio Phosphoruscontaining additive on the label 184±4 185.5±2 213±8 178.2±2 22.17 23.15 24.08 20.44 8.3 8.01 8.85 8.72 No No No No 181.12±29 171.9±8 217±23 241.2±24 204.67±7 185.25±3 153.37±28 136.83±9 155.5±9 223.03±5 144.7±5 22.2 21.6 24.65 28.4 23.57 21.8 17.38 14.69 19.54 23.32 15.27 8.15 8.2 8.82 8.49 8.68 8.49 8.82 9.31 7.96 9.56 9.48 No No No No No No No No No No No 170±37 175±8 14.09 18.59 12.07 9.41 No No Meat in breadcrumbs La Cocinera frozen chicken nuggets Frinka frozen chicken nuggets Burger King chicken fillet Hacendado frozen chicken nuggets Eroski frozen chicken nuggets 103.90±2 117±16 179.3±10 132.77±11 162.20±3 10.98 10.42 16.22 11.60 13.71 9.46 11.47 11.05 11.45 11.83 No E450-631 --E450 E450 Processed meats Mackein barbecue chicken wings Burger King fried chicken leg and wings Casa Matachín refrigerated chicken meatballs Eroski Basic frozen chicken croquettes Hacendado frozen chicken croquettes Martínez Loriente marinated turkey breasts Carrefour turkey and cheese Flamenquín croquettes Oscar Mayer turkey Frankfurter Carrefour refrigerated chicken roti Carrefour refrigerated chicken wrap Hacendado frozen meatballs Refrigerated breaded pork steak with cheese Oscar Mayer Classic Wiener Frankfurter Jumbo Cheese Oscar Mayer Frankfurter Carrefour French toast sandwiches 139.3±12 206.8±6 152.7±7 44.7±7 74.43±13 205±16 251.60±10 221.1±4 273.73±30 259.27±10 108.47±1 171.9±10 211.1±8 262.3±10 272.2±20 21.95 30.46 15.69 4.34 4.70 13.80 13.23 11.13 12.80 11.14 10.8 12.77 11.33 13.08 10.4 6.35 6.79 9.73 10.3 15.84 14.86 19.02 19.86 21.39 23.27 10.04 13.46 18.62 20.05 26.17 No --No No No E450-451 E450-451 E451 E451 E339 E450 E451-322 E451 E451-340 E450-451 Fresh meat Simply pork loin Simply beef Simply chicken breast Simply skinless chicken leg Refrigerated meat Simply pork loin Eroski pork loin Eroski Natur Selection pork loin Eroski Natur Selection sirloin Martínez Loriente loin fillet/scallops Simply beef Martínez Loriente beef/pork mince Martínez Loriente beef/pork burger Eroski skinless chicken leg Carrefour chicken breast Martínez Loriente chicken/turkey sausages Frozen meats Martínez Loriente frozen loin chop Carrefour skinless chicken drumsticks CITA: phosphorus values by spectophotometry and protein values by the Kjeldahl method tested in the Aragón Agri-Food Research Centre. 502 Nefrologia 2014;34(4):498-506 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD short original Table 3. Results of the phosphorus and protein composition of foods and the phosphorus-protein ratio according to the tests by the Aragón Agri-Food Research Centre. Fresh, frozen and breaded fish and surimi. PhosphorusCITA phosphoruscontaining protein ratio additive on the label Phosphorus mg/100 CITA Protein mg/100 CITA Fresh fish Simply hake Simply squid Simply salmon 154.32±8 78.23±9 176.23±7 18.36 9.26 17.14 8.41 8.42 10.28 No No No Frozen fish Findus skinless hake Mascatto hake fillets Eroski catfish fillet Pescanova salmon pieces Eroski salmon Carrefour frozen swordfish Simply Aligator squid rings Carrefour squid rings Eroski squid rings Simply Aligator cleaned squid 125.1±9 162.37±11 131.10±8 213.3±18 213.21±12 208.5±6 101.42±9 78.33±9 146.10±9 53.12±6 16.93 17.08 11.49 20.14 20.09 17.49 11.50 7.27 11.27 8.62 7.39 9.51 11.40 10.59 10.6 11.92 8.78 10.77 12.96 6.15 No No E451 No No No No E338 No No Breaded fish Pescanova fish burgers Pescanova breaded hake pieces Findus breaded hake fillets Carrefour hake nuggets Pescanova egg-battered hake fillets Pescanova hake surfers Pescanova stewed cod Hacendado squid rings Eroski fried squid rings Pescanova Caprichos fried squid rings Eroski breaded crab claw surimi Pescanova breaded crab claw surimi Frudesa surimi 68.3±11 145.4±8 118.8±4 103.67±8 157.6±18 162.3±6 137.3±3 78.3±3 114.6±9 122.5±12 42.60±3 58.00±5 28.30±1 9.30 9.72 12.15 9.87 12.03 11.24 12.60 7.25 7.28 6.49 5.84 5.76 5.39 7.31 14.96 9.51 10.50 13.10 14.44 10.90 10.8 15.65 18.98 7.29 10.07 5.25 E635 E451 No No No E450 E450 E339 E450 E450 E450 E450-E635 E450-E635 Refrigerated/prepared Carrefour cannelloni bolognese Eroski fresh refrigerated spaghetti carbonara Eroski noodles Eroski frozen vegetable lasagne Buittoni Piacere vegetable tortelloni Casa Tarradellas ham and cheese pizza Casa Tarradellas Neapolitan pizza Buitoni Prosciuto e Fromaggio frozen pizza Casa di Mama Prosciuto Funghi frozen pizza Hacendado ham and cheese pizza Hacendado refrigerated tuna pies Hacendado frozen patties La Cocinera frozen tuna patties Seleqtia lentils, duck and mushrooms Carrefour refrigerated Valencian-style paella Cheese panini 66.37±1 49.20±5 67.90±12 54.10±3 112.30±5 195.20±12 170.30±11 166.60±8 210.10±14 193.83±4 72.17±4 62.10±8 69.00±5 87.00±3 76.43±7 203.33±9 4.16 3.84 5.29 3.40 8.31 13.47 11.71 10.67 8.92 12.96 7.26 6.48 7.63 4.97 5.74 13.09 15.95 12.82 12.84 15.90 13.51 14.49 14.54 15.61 23.55 14.96 9.94 9.58 9.05 17.51 13.32 15.53 E452 No E452 E339-E631 No E451 E451 No E452 E451 E450 No No No No No 21.43±6 28.20±9 1.20 0.67 17.86 42.09 No No Sauces Hacendado tomato sauce Kraft mayonnaise CITA: phosphorus values by spectophotometry and protein values by the Kjeldahl method tested in the Aragón Agri-Food Research Centre. Nefrologia 2014;34(4):498-506 503 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD short original Table 4. Phosphorus-protein ratio according to the values of the food composition tables. Dairy products, cereals, cold meats, refrigerated-frozen products and fish. CESNID phosphorusprotein ratio Moreiras phosphorusprotein ratio BEDCA phosphorusprotein ratio Dairy products Whole milk Soy milk Natural yogurt Prebiotic yogurt Custard Burgos fresh cheese Cheese slices Grating cheese 27.7 --25.7 30 26.5 13.7 47.8 25.4 27.9 --45.9 --26.1 40 58.5 20.3 30.1 14.7 29.7 --29.7 13.7 56.5 21.6 Cereals Marie biscuits White bread Sliced bread Non-iced fairy cakes Sobao cakes Croissants Doughnuts Chocolate cookies 12.7 10.8 12.5 37.9 --16.5 15.6 13.2 27.1 13.7 9.8 22.1 10.3 15.7 13.3 27.1 12.7 10.8 12.5 37.9 --12.7 13.3 13.2 Cold meats Smoked bacon Chopped pork Chorizo Extra fuet Cooked ham Cooked ham without phosphates Pork loin Longaniza sausage Bologna sausage Cold turkey meat Salchichón sausage 8.1 --12 5.1 12.8 --6.4 --7.1 --11.5 11.1 11.4 7.3 5.1 5 --3.6 --11.4 9.2 10.1 8.3 11.4 10 7.8 11.4 --5.3 6.4 11.4 17.7 10.1 Refrigerated-frozen Frozen pizza Meat cannelloni with white sauce Lasagne with white sauce Spaghetti Pasta filled with meat Pasta filled with cheese Meat pie Tuna pasty Paella 21.8 7.5 14.7 15 14.9 9.1 3.1 ----- 18.3 17.6 14.8 15.8 14.9 9.1 ------- 21.8 7.5 14.7 15 14.9 --8.5 51.1 5.9 Fish Salmon Swordfish 16.8 20.1 12 14.5 13.6 29.8 BEDCA: Spanish Food Composition Database, CESNID: Nutrition and Diet Higher Education Centre food composition table, Moreiras: Moreira O food composition table. 504 Nefrologia 2014;34(4):498-506 Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD confusing. In general, they have additives and high amounts of phosphorus, although, in some cases the phosphorusprotein ratio would mean they could be included to a limited extent in our patients’ diets: meatballs and chicken croquettes, pies and tuna patties, fresh spaghetti and fideuà. We also found that some simple pizzas (romana, cooked ham and cheese pizza) do not contain excessively high quantities of phosphorus. Products without phosphorus additives have a phosphorus-protein ratio of 13.3mg/g and those that contain these additives have a ratio of 18.7mg/g. DISCUSSION The increased consumption of processed foods, with the extensive use of phosphorus additives, complicates dietary management of CKD patients. The diverse application of these additives (pH regulators, antioxidants, protein stabilisers, flavour enhancers, colour enhancers, melting salts in cheeses, dough enhancers and baking powder) means that they may contribute up to a third of dietary phosphorus15. Leon et al., in supermarkets in the US, detected that almost 50% of foods have phosphorus-containing additives, increasing the phosphorus quantity by 67mg/100g. The presence of additives is common in refrigerated-frozen and packaged products, cereals and yogurts, and in general, the products that contain them are cheaper16. Current regulations make phosphorus contribution estimations difficult: producers are not required to display their quantities on the labels, variable quantities are allowed, since they can set their limit according to maximum amounts and the contribution of these additives is not clearly defined in the food composition tables17. Therefore, we must interpret the phosphorus contribution calculation with caution by dietary survey18, and we recommend questionnaires that record the normal intake of different foods and their form of preparation19. In the dietary education of CKD patients, we must be aware of this extra contribution in the form of hidden phosphorus20. Some authors are optimistic and consider that by recognising the problem, we can provide better options21. However, poor knowledge of the phosphorus content of many products limits our actions, which do not usually go beyond recommending intake of non-processed foods. This option is increasingly complicated, since in modern society, processed foods surround our patients, making regular access to natural foods difficult. We must study more specific dietary interventions that include information about phosphorus-containing additives. Of the list of additives authorised, only a few are a source of phosphorus and they are displayed on labels with a letter and number format: phosphoric acid (E338), phosphates (E339, E340, E341, E343), diphosphates (E450), triphosphates (E451) and polyphosphates (E452). Sullivan et al. achieved a moderate but significant decrease in serum Nefrologia 2014;34(4):498-506 short original phosphorus levels of 0.6mg/dl, by adding data on phosphoruscontaining additives to patient dietary information22. Other factors complicate the limitation of phosphorus contributions. The quantities permitted are relatively high, since their limits are designed more to avoid fraud than being based on a dietary risk; in some products (refrigerated, frozen and packaged foods in supermarkets), the regulations allow phosphorus-containing additives without a specific indication thereof on the list of ingredients23 and in other processed products (pizza, tortellini, cheese paninis, etc.), it is surprising that there are no phosphorus-containing additives on the labels. This may be due to current legislation, which according to the “General regulations for labelling, presentation and advertising of foodstuffs”, it is not compulsory to declare in the list of ingredients additives from an ingredient if they do not have a technological function in the final product. This means that in prepared or pre-cooked products, there may be prepared dough with phosphorus-containing additives, melted cheese with phosphates, crab sticks with phosphates, etc. whose phosphorus content is not listed on the labels. In this study on 118 products, we aim to provide complete information about the phosphorus content of the processed products reviewed in previous studies10,24, displaying data on the normal foods in our setting, noting the differences with fresh food and the discrepancy with food composition tables. We consider it important to remark that nephrologists, nutritionists and nephrology nursing staff should be aware of these barriers in order to recognise a potential for the reduction of phosphorus, while maintaining protein intake. Intake of natural foods that are not pre-cooked and the phosphorus content of some soft drinks (particularly cola) are important aspects that we should consider25. The study limitations are those that are unavoidable in any approach to this problem. It was a cross-sectional study carried out in a specific geographic area, new products often appear and at any time there may be changes in the processing of the food, which may alter its phosphorus content (the quantities permitted according to current legislation are indicated with “up to xxx grams of P205 per kg or litre”, with a generally high level that may be variable). These limitations highlight the importance of the need for dietary advice clinics and prospective studies to assess whether we can adopt truly effective measures. We must be aware of the excessive phosphorus contribution of phosphorus additives without protein contribution. Patients must be provided with this information at dietary advice clinics, and must individually become accustomed to reviewing product labels; prospective studies are recommended to assess the effectiveness of the measures. It is obvious that this problem requires healthcare policy actions, such as changes to the labelling that make it compulsory to display the real phosphorus content of the product and encourage the 505 short original preparation of products with a low phosphorus content and alternatives to phosphorus additives. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. REFERENCES 1. Tentori F, Blayney M, Albert J, Gillespie B, Kerr P, Bommer J, et al. Mortality risk for dialysis patients with different levels of serum calcium, phosphorus, and PTH: the Dialysis Outcomes and Practice Patterns Study (DOPPS). Am J Kidney Dis 2008;52:519-30. 2. Dhingra R, Sullivan LM, Fox CS, Wang TJ, D´Agostino RB, Gaziano JM, et al. Relation of serum phosphorus and calcium levels to the incidence of cardiovascular disease in the community. Arch Intern Med 2007;167:879-85. 3. Sax L. The Institute of Medicine´s «Dietary Reference Intake» for Phosphorus: A critical perspective. J Am Coll Nutr 2001;20:271-8. 4. Calvo M, Uribarri J. Public health impact on dietary phosphorus excess on bone and cardiovascular health in the general population. Am J Clin Nutr 2013;98:6-15. 5. Arnaudas L, Caverni A, Vercet A, Bielsa S, Etaaboudi S, Lou LM, et al. Fuentes ocultas de fósforo: presencia de aditivos con contenido en fósforo en los alimentos procesados. Nefrologia 2011;31:44. 6. Uribarri J. Phosphorus aditives in food and their effect in dialysis patients. Clin J Am Soc Nephrol 2009;4:1290-2. 7. Reglamento (UE) Nº 1129/2011 del Parlamento Europeo y del Consejo de 11 de Noviembre de 2011 para establecer una lista de aditivos alimentarios de la Unión Europea. Diario Oficial de la Unión Europea. 12 Noviembre 2011, L 295/1-177. 8. Reglamento (UE) Nº 1169/2011 del Parlamento Europeo y del Consejo de 25 de Octubre de 2005 sobre la información facilitada al consumidor. Diario Oficial de la Unión Europea. 22 Noviembre 2011, L 304/18-83. 9. Sullivan CM, Leon JB, Sehgal AR. Phosphorus containing food additives and the accuracy of nutrient databases: implications for renal patients. J Ren Nutr 2007;17:350-4. 10. Lou LM, Caverní A, Arnaudas L, Vercet A, Gimeno JA, Sanz-París A, et al.; en representación del Grupo de Investigación ERC Aragón, IACS. Impacto del procesamiento de los productos cárnicos y pescados en la ingesta de fósforo en los pacientes con enfermedad renal crónica. Nefrologia 2013;33:797-807. 11. Barril-Cuadrado G, Puchulu MB, Sánchez Tomero JA. Tablas de ratio fósforo/proteína de alimentos para población española. Utilidad en la enfermedad renal crónica. Nefrologia 2013;33:362-71. Luis M. Lou-Arnal et al. Phosphorus-containing additives in CKD 12. Moreiras O, Carbajal A, Cabrera L, Cuadrado C. Tablas de composición de alimentos. Madrid: Ediciones Pirámide (Grupo Anaya SA); 2011. 13. Tablas de Composición de Alimentos del CESNID (Centro de Enseñanza Superior de Nutrición y Dietética). Madrid: McGraw Hill/Interamericana de España; 2004. 14. Bedca.net [Internet]. España: Red BEDCA Ministerio de Ciencia e Innovación, Agencia Española de Seguridad Alimentaria y Nutrición, Ministerio de Sanidad y Política Social [accessed August 26, 2010]. Available at: http://www.bedca.net 15. US Department of Agriculture, Agricultural Research Service. Nutrient Intakes from Food: Mean Amounts Consumed per Individual, by Race/ Ethnicity and Age. What We Eat in America; NHANES 2009-2010. Available at: www.ars.usda.gov/ba/bhnrc/fsrg. [accessed November 4, 2012]. 16. León J, Sullivan C, Sehgal A. The prevalence of phoshorus-containing food additives in top selling food in grocery stores. J Ren Nutr 2013;23:265-70. 17.Uribarri J. Phosphorus homeostasis in normal health and in chronic kidney disease patients with special emphasis on dietary phosphorus intake. Semin Dial 2007;20(4):295-301. 18. Murtaugh M, Filipowicz R, Baird B, Wei G, Greene T, Beddhu S. Dietary phosphorus intake and mortality in moderate chronic kidney disease: NHANES III. Nephrol Dial Transplant 2012;27:990-6. 19.Noori N, Kalantar-Zadeh K, Kovesdy C, Bross R, Benner D, Kopple J. Association of dietary phosphorus intake and phosphorus to protein ratio with mortality in hemodialysis patients. Clin J Am Soc Nephrol 2010;5:683-92. 20. Cupisti A, Ferretti V, D´Alesandro C, Petrone I, Di Giorgio A, Meola M, et al. Nutritional knowledge in hemodialysis patients and nurses: focus on phosphorus. J Ren Nutr 2012;22:541-6. 21. Gutiérrez O. Sodium and phosphorus based food additives: persistent but surmountable hurdles in the management of nutrition in chronic kidney disease. Adv Chronic Kidney Dis 2013;20:150-6. 22. Sullivan C, Sayre SS, Leon JB, Machekano R, Love TE, Porter D, et al. Effect of food additives on hyperphosphatemia among patients with end-stage renal disease. A randomized controlled trial. JAMA 2009;301:629-35. 23. Sherman RA, Mehta O. Phosphorus and potassium content of enhanced meat and poultry products: implications for patients who receive dialysis. Clin J Am Soc Nephrol 2009;4:1370-3. 24. Arnaudas L, Caverní A, Lou LM, Vercet A, Gimeno-Orna JA, Moreno R, et al. Fuentes ocultas de fósforo: presencia de aditivos con contenido en fósforo en los alimentos procesados. Diálisis y Trasplante 2013;34:1549. 25.Kalantar-Zadeh K, Gutekunst L, Mehrotra R, Kovesdy CP, Bross R, Shinaberger CS, et al. Understanding sources of dietary phosphorus in the treatment of patients with chronic kidney disease. Clin J Am Soc Nephrol 2010;5:519-30. Sent to review: 30 Dec. 2013 | Accepted: 7 Apr. 2014 506 Nefrologia 2014;34(4):498-506 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society originals Evolution of antibody titre against the M-type phospholipase A2 receptor and clinical response in idiopathic membranous nephropathy patients treated with tacrolimus Alfons Segarra-Medrano1, Elías Jatem-Escalante2, Clara Carnicer-Cáceres3, Irene Agraz-Pamplona1, M. Teresa Salcedo4, Naiara Valtierra1, Elena Ostos-Roldán1, Karla V. Arredondo1, Juliana Jaramillo1 1 Servicio de Nefrología. Hospital Universitari Vall d’Hebron. Barcelona (Spain); 2 Escuela de Doctorado. Universidad Autónoma de Barcelona (Spain); 3 Servicio de Bioquímica. Hospital Universitari Vall d’Hebron. Barcelona (Spain); 4 Servicio de Anatomía Patológica. Hospital Universitari Vall d’Hebron. Barcelona (Spain) Nefrologia 2014;34(4):491-7 doi:10.3265/Nefrologia.pre2014.Jun.12536 ABSTRACT Introduction and objectives: The level of circulating antibodies against M-type phospolipase A2 receptor has been reported as having a significant correlation with clinical activity in idiopathic membranous nephropathy. However, the usefulness of monitoring antibody titre as a predictor of clinical response following the onset of treatment has not been formally analysed. The predictive value of the evolution of anti-PLA2R antibody titre on the clinical response of idiopathic membranous nephropathy patients treated with tacrolimus is analysed in the following study. Patients and Method: 36 patients with nephrotic syndrome secondary to idiopathic membranous nephropathy with immunosuppressive treatment indication criteria were treated with tacrolimus in monotherapy. The level of anti-PLA2R antibodies was determined before treatment and at 3, 6, 9 and 12 months after the onset of treatment. The study analysed the predictive value of the reduction in antibody titre and the relative and absolute reduction in antibody titre at 3 and 6 months over the period until remission and on the probability of remission at 6, 9 and 12 months. Results: The relative reduction in the anti-PLA2R antibody titre was significantly greater in those patients with remission and it preceded the clinical response. No association was observed between the antibody titre prior to treatment and the mean response time or the response at 12 months. Reduction in antibody titre is significantly associated with the time until Correspondence: Elías Jatem Escalante Escuela de Doctorado. Universidad Autónoma de Barcelona. Idumea, 08035. (Spain). [email protected] [email protected] signs of remission. Relative reduction in anti-PLA2R antibody titre at 3 months had a high sensitivity and specificity to predict the response at 6 and 9 months, but not at 12 months; however the relative reduction in the antibody titre at 6 months had a high sensitivity and specificity for predicting the response at 12 months. Conclusion: In patients with IMN associated with antiPLA2R antibodies, the monitoring of antibody titre following the onset of treatment is useful for estimating the time period until remission and predicting the probability of remission at 12 months. Keywords: Anti PLRA2 antibodies. Idiopathic membranous nephropathy. Tacrolimus. Evolución del título de anticuerpos contra el receptor tipo M de la fosfolipasa A2 y respuesta clínica en pacientes con nefropatía membranosa idiopática tratados con tacrolimus RESUMEN Introducción y objetivos: Se ha descrito que el nivel de anticuerpos circulantes contra el receptor tipo M de la fosfolipasa A2 tiene correlación significativa con la actividad clínica de la enfermedad en la nefropatía membranosa idiopática (NMI). Sin embargo, la utilidad de la monitorización del título de anticuerpos como predictor de respuesta clínica tras el inicio del tratamiento no ha sido formalmente analizada. En el siguiente estudio se analiza el valor predictivo de la evolución del título de anticuerpos antiPLA2R sobre la respuesta clínica en enfermos con NMI tratados con tacrolimus. Pacientes y métodos: 36 enfermos con síndrome 491 originals nefrótico secundario a NMI, con criterios de indicación de tratamiento inmunosupresor, fueron tratados con tacrolimus en monoterapia. Se determinó el nivel de anticuerpos anti-PLA2R antes del tratamiento y a los 3, 6, 9 y 12 meses tras su inicio. Se analizó el valor predictivo de la pendiente de reducción en el título de anticuerpos y de la reducción absoluta y relativa en el título de anticuerpos a los 3 y 6 meses sobre el tiempo hasta la remisión y sobre la probabilidad de remisión a los 6, 9 y 12 meses. Resultados: La reducción relativa en el título de anticuerpos anti-PLA2R fue significativamente mayor en los enfermos que presentaron remisión y precedió a la respuesta clínica. No se apreció asociación entre el título de anticuerpos previo al tratamiento con el tiempo medio de respuesta o la respuesta a los 12 meses. La pendiente de reducción en el título de anticuerpos se asoció significativamente con el tiempo hasta la evidencia de remisión. La reducción relativa en el título de anticuerpos anti-PLA2R a los 3 meses tuvo una elevada sensibilidad y especificidad para predecir la respuesta a los 6 y 9 meses, pero no a los 12 meses, mientras que la reducción relativa en el título de anticuerpos a los 6 meses tuvo una elevada sensibilidad y especificidad para predecir la respuesta a los 12 meses. Conclusión: En enfermos con NMI asociada a anticuerpos anti-PLA2R, la monitorización del título de anticuerpos tras el inicio del tratamiento es útil para estimar el período de tiempo hasta la remisión y para predecir la probabilidad de remisión a los 12 meses. Palabras clave: Anticuerpos anti-PLA2R. Nefropatía membranosa idiopática. Tacrolimus. INTRODUCTION Idiopathic membranous nephropathy (IMN) is an antibodymediated disease caused by IgG and C3 deposits in the subepithelial space of the glomerular basement membrane1,2. There is currently agreement that patients with normal renal function who suffer from nephrotic syndrome for more than 6-12 months after diagnosis are candidates for receiving immunosuppressive therapy. The drugs whose efficacy has been proven in randomised clinical trials and which are considered the drugs of choice as the first line of treatment are alkylating agents combined with steroids and calcineurin inhibitors3,4. Both treatments have proven similar efficacy in inducing nephrotic syndrome remission and preserving renal function, but they have some limitations. Firstly, around 20% of patients may be resistant to one or both drugs3-13. Secondly, the available evidence suggests that after starting therapy, the probability of a response progressively increases with time, even beyond the period of exposure to the drug5-13, and there is currently no variable that allows us to predict whether the patient will respond or not to the treatment or the time at which the response will occur. Recently, the M-type phospholipase A2 receptor has been identified as one of the target antigens of the autoimmune response in IMN patients14-16 and it has been reported that circulating antibodies against the latter (anti492 Alfons Segarra-Medrano et al. Anti-PLA2R titre and evolution of IMN PLA2R), present in approximately 70%-75% of patients, have a significant correlation with the clinical activity of the disease17,18. As such, the evolution the anti-PLA2R antibody titre after the start of treatment could be useful for predicting the response. Some evidence indicates that after treatment with rituximab the reduction in the antibody titre precedes the remission of proteinuria 19. However, the usefulness of monitoring the antibody titre as a predictor of clinical response has not been formally analysed and there are no data on the evolution of the anti-PLA2R antibody titre in patients treated with tacrolimus. In this study, repeated measurements of the anti-PLA2R antibody titre were carried out before and during the 12 months following the start of treatment in patients with IMN who received tacrolimus, with the objective of analysing the predictive value of the anti-PLA2R antibody titre evolution on the clinical response. PATIENTS AND METHOD We included a total of 36 patients who fulfilled the following criteria: 1. Age >18 years old. 2. Nephrotic syndrome caused by IMN confirmed by renal biopsy. 3. Exclusion of secondary aetiologies. 4. Anti-PLA2R antibody titres >20RU/ml at the time of diagnosis. 5. Immunosuppressive therapy criteria due to persistence of the nephrotic syndrome after 6 months of symptomatic treatment with angiotensin receptor blockers, statins, diuretics and a low-sodium diet, in accordance with the treatment guidelines3,4. 6. Normal renal function, as defined by a CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) value >60ml/min/1.73m2. The renal biopsies were stained with haematoxylin and eosin, PAS, methenamine silver and Masson’s trichrome stainings for the morphological analysis and we carried out immunofluorescence studies with antibodies against IgA, IgG, IgM, C3, fibrinogen and light chains. The diagnosis of IMN was carried out in the presence of a compatible morphological pattern, associated with evidence of subepithelial IgG and C3 deposits in the immunofluorescence. At the time of diagnosis, patients received treatment with angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers, a low-sodium diet and treatment for dyslipidaemia with statins. After a 6-month observation period and after observing no spontaneous remission, all patients received monotherapy with tacrolimus at an initial dose of 0.06mg/kg/day, which was subsequently adjusted to maintain target levels of 7ng/ml-9ng/ml after 12 hours. No patient had previously received immunosuppressive therapy. Treatment with tacrolimus was maintained for three months after evidence of remission or a maximum of 12 months in Nefrologia 2014;34(4):491-7 Alfons Segarra-Medrano et al. Anti-PLA2R titre and evolution of IMN cases in which patients had not shown remission at the end of this period. After evidence of total or partial remission, the tacrolimus dose was reduced at a rate of 30% per month until total suppression or recurrence. Per protocol, all patients were tested monthly until there was evidence of remission, and if there was remission, they were tested every 2-3 months until suppression of treatment, evidence of recurrence or the absence of a response after 12 months. In all patients included, serum samples were extracted before and after the start of treatment every three months until the end of the first year. These samples were used to determine the anti-PLA2R antibody titre by ELISA (Euroimmun, Lübeck, Germany; linearity: 6-1500RU/ml; lower limit of detection 0.6RU/ml). The outcome variables were the probability of obtaining total or partial remission in the course of the 12 months following the start of treatment, the time period between the start of treatment and evidence of remission, the evolution of the antibody titre during the observation period and the percentage of patients who had a negative antibody titre at the end of the 12-month observation period. Definitions: - Complete remission: proteinuria <0.3g/day, albumin >3.5g/dl and glomerular filtration rate >60ml/min/1.73m2. - Partial remission: >50% reduction in baseline proteinuria, with the last test showing <3.5g/day and with a glomerular filtration rate >60ml/min/1.73m2. - No response: absence of complete or partial remission 12 months after the start of treatment. - Negative antibody titre: anti-PLA2R antibody titre <20RU/ml. This study followed the parameters of the Declaration of Helsinki. All patients gave their written informed consent and the study was approved by the hospital’s bioethics committee. Statistical analysis The results are expressed as a mean and standard deviation for the variables with normal distribution and as a median and quartiles for variables whose distribution is not normal. The differences in proportions were analysed using the χ2 test or Fisher’s exact test. The analysis of the antibody titre evolution over time was carried out using analysis of variance for repeated measurements. In order to study the predictive value of the reduction in the antibody titre on the response, we calculated the absolute and relative reduction of the antibody titre after 3 and 6 months in relation to the baseline value, as well as the reduction slope in the antibody titre during the follow-up period, expressing it in RU/ml/month. We carried out a univariate analysis to identify the variables associated Nefrologia 2014;34(4):491-7 originals with the probability of remission during the 12-month observation period through the Kaplan-Meier method, using the log-rank test for comparison between groups. The relationship between the reduction slope in the antibody titre and time until evidence of remission was calculated using a simple linear regression. Using ROC curves, we analysed the anti-PLA2R antibody titre reduction value after 3 and 6 months that had the greatest sensitivity and specificity for identifying patients in remission after 3, 6, 9 and 12 months. Differences were considered to be statistically significant when p was <.05. The version 20.0 SPSS statistical software was used. RESULTS Table 1 summarises the baseline clinical and biochemical characteristics of the total number of patients included in the study in terms of their response to treatment after 12 months. No significant variables were observed in any of the variables analysed between those patients who responded and those who did not. Over the 12 months of follow-up (Figure 1), the probability of remission increased progressively over time, with a 40% probability after 6 months, 60% after 9 months and 69.4% (25/36 patients) after 12 months. Of the total number of patients in remission, 9 (25%) showed complete remission and 16 (75%) showed partial remission. The median time between the introduction of treatment and evidence of remission was 8.5 months (interquartile range: 5.5-9.6 months). The percentage of patients who entered total or partial remission without treatment with tacrolimus after 12 months was 28% (7/25). The mean tacrolimus dose was 0.05±0.017mg/kg/ day and the mean level was 7.9±1.9ng/ml without significant differences being observed between those who responded and those who did not. During the observation period, there was no recurrence in any patient when tacrolimus therapy was discontinued. Figure 2 displays the evolution of the antibody titre according to the response to treatment in the total group of 36 patients studied. In relation to the baseline value, in the group of patients, the relative reduction in the antibody titre at the end of the 12-month observation period was 61.3±37% (p:.004). There were no differences in the baseline antibody levels between patients who entered remission and those who did not. Following treatment, the antibody titre after 3, 6, 9 and 12 months was significantly lower in those who showed total or partial remission (F: 25.9, p:.000) than in those who did not respond to treatment. The mean anti-PLA2R antibody titre at the time of remission was 17.4±8.3RU/ml. Twenty of the 25 (80%) patients who entered remission had an anti-PLA2R antibody titre <20RU/ml at the time of remission. Figure 3 displays the evolution of the anti-PLA2R antibody titre and proteinuria in patients who did not respond to treatment. 493 Alfons Segarra-Medrano et al. Anti-PLA2R titre and evolution of IMN originals Table 1. Baseline clinical and biochemical characteristics and therapeutic response N Total Remission No remission 36 25 11 P Sex (male) n (%) 25 (69.4) 17 (68) 8 (72.7) 0.91 Age (years) 49.5±15.1 51.5±15.3 42.3±17.8 0.13 Total cholesterol (mg/dl) 339.2±83.1 331.8±66.4 355.36±33.1 0.31 Albumin (g/dl) 2.1±0.42 2.06±0.53 2.19±0.53 0.44 Creatinine (mg/dl) 0.98±0.2 1±0.19 0.95±0.25 0.62 eGFR (ml/min/1.73m2) 114±21 108±26 120±20.7 0.30 Proteinuria (g/24 h) 11.3±3.2 10.5±2.9 12.8±3.5 0.22 Anti-PLA2R antibody titre (RU/ml) Time since diagnosis (months) Diabetes n (%) 225±81 222.4±98 231±92 0.43 10.7±3.14 10.6±2.8 10.8±4.5 0.85 3 (8.3) 2 (8) 1 (9) 0.58 High blood pressure n (%) 7 (19.4) 5 (20) 2 (18.1) 0.74 Smokers n (%) 6 (16.6) 4 (16) 2 (18.1) 0.74 Ischaemic heart disease n (%) Body mass index n (%) 2 (5.5) 1 (4) 1 (9) 0.86 24.9±4.9 24.8±4.9 25.1±5.1 0.49 eGFR: estimated glomerular filtration rate. We can observe a statistically significant reduction in the antibody titre between the baseline level and the third month (18.5±4.8%, p:.037) and an accumulated 21.4±13.6% reduction in the antibody titre after 12 months. The reduction slope in the antibody during the 12-month follow-up in patients who did not respond to treatment was 7.53±5.50RU/ml/month. Over the course of the follow-up period, we did not observe significant changes in urine protein excretion. Probability of remission (%) 1.0 0.8 0.6 0.4 0.2 0.0 0.0 2.04.06.08.0 10.012.0 Time (months) Figure 1. Probability of remission and time in the sample studied. 494 Figure 4 displays the evolution of the anti-PLA2R antibody titre and proteinuria in patients who showed remission. The relative reduction in the antibody titre preceded the decrease in proteinuria and it was statistically significant from the third month. The relative reduction in the antibody titre was 35±18.4% after 3 months, 60±16.4% after 6 months, 70±12% after 9 months and 78.9±14.2% after 12 months. The reduction slope in the antibody titre during the observation period in patients who responded to treatment was -21.5±3.78RU/ ml/month. Using a simple regression analysis, we observed a statistically significant relationship between the antibody titre reduction rate and the time until remission (Table 2). Table 3A summarises the value of relative reduction in the antibody titre after three months on the prediction of response to treatment after 6, 9 and 12 months. Table 3B summarises the value of the relative reduction in the antibody titre after 6 months on the prediction of the response to treatment after 9 and 12 months. It can be observed that the relative reduction in the antibody titre after 3 months has increased sensitivity and specificity for predicting the response after 6 and 9 months but not after 12 months, while the relative reduction in the antibody titre after 6 months has an increased sensitivity and specificity for predicting the response after 9 and 12 months. DISCUSSION In this study, we carried out repeated measurements of the anti-PLA2R antibody titre before and during the 12 months following the start of treatment in patients with IMN who received tacrolimus as the first line of treatment, with the objective of analysing the predictive value of the evolution Nefrologia 2014;34(4):491-7 Anti-PLA2R antibody titre (RU/ml) Alfons Segarra-Medrano et al. Anti-PLA2R titre and evolution of IMN originals of the anti-PLA2R antibody titre on the clinical response. The patient group included a non-selected sample of patients with IMN associated with anti-PLA2R antibodies, who were treated by following the same protocol, after an extended period of symptomatic treatment starting at diagnosis in accordance with recommendations of different guidelines3,4. The observation period was 12 months, which is the maximum period in which monotherapy with tacrolimus was maintained if no response was observed. Both the probability of remission observed over time and the percentage of patients in remission after 12 months observed in our patients were very similar to those reported in previous studies with calcineurin inhibitors11-13. For these reasons, the results observed in our patients could be applied to other patient groups with IMN who receive tacrolimus. 250.0 200.0 150.0 100.0 50.0 0.0 Start 3 months 6 months 9 months 12 months Time (months) Remission No remission Figure 2. Anti-PLA2R antibody titre and remission in the sample studied. The error bars represent the mean ± the standard error of the mean. 250.0 The results of our study provide the following data of clinical interest. Firstly, similarly to the data reported after treatment with rituximab19,20, our results indicate that in patients treated with tacrolimus, the reduction in the anti-PLA2R antibody titre after the start of treatment precedes the remission of proteinuria and is related to the clinical response. The evidence of a progressive reduction in the antibody titre was highly predictive of remission, while persistence of high titres was associated with the persistence of nephrotic syndrome, 250.0 200.0 200.0 150.0 150.0 * 100.0 100.0 50.0 50.0 0.0 0.0 Start 3 months 6 months 9 months 12 months Time (months) Anti-PLA2R antibody titre (RU/ml) Proteinuria (gr/24h x 10) Figure 3. Evolution of proteinuria and the anti-PLA2R antibody titre in patients without remission in the observation period. For the purposes of graphic representation and in order to standardise the measurement scales, proteinuria values are represented as g/day x 10. The error bars represent the mean ± the standard error of the mean. Nefrologia 2014;34(4):491-7 * Start 3 months 6 months 9 months 12 months Time (months) Anti-PLA2R antibody titre (RU/ml) Proteinuria (g/24 h x 10) Figure 4. Evolution of proteinuria and the anti-PLA2R antibody titre in patients with remission in the observation period. For the purposes of graphic representation and in order to standardise the measurement scales, proteinuria values are represented as g/day x 10. The error bars represent the mean ± the standard error of the mean. 495 Alfons Segarra-Medrano et al. Anti-PLA2R titre and evolution of IMN originals Table 2. Relationship between the antibody titre reduction slope and the time until remission in patients who responded to the treatment (Constant) Reduction slope b ET T Sig 95% confidence interval for β 22.1 1.354 16.3 0.000 19.344 24.976 –0.61 0.051 -10.5 0.000 –0.688 –0.461 Reduction slope expressed in RU/ml/month. R2: 0.84, P:.000. with statistically significant differences in the antibody titre between patients with and without a response, which were evident from the third month and they were maintained throughout the whole observation period. Furthermore, in patients who responded to treatment, the antibody level reduction rate was associated with the speed of the clinical response. Both data indicate that monitoring the anti-PLA2R antibody titre after the start of treatment is useful in clinical practice and it may have two practical implications. The first is that the antibody titre reduction rate after the start of treatment may be used as an estimator of the response time. The second is that the relative reduction in the antibody titre after 3 and 6 months may serve as a guide for predicting the response probability. Given that the available evidence indicates that the response to treatment with tacrolimus increases progressively with the drug exposure time13 and that none of the baseline clinical or biochemical characteristics allow the probability of response to treatment to be calculated, in patients who show late responses, a relative reduction value in the antibody titre equal to or greater than 50% after 6 months may be a useful criterion when making the decision to maintain immunosuppressive therapy, while the persistence of reductions lower than this figure after 6 and 9 months has to suggest a high probability of resistance to treatment. IMN is an antibody-mediated glomerulopathy. In approximately 70% of cases, these antibodies are directed against the M-type phospholipase A2 receptor. In 30% of cases, the antibodies are not identified either in their circulating form or deposited in the glomerular basement membrane. The identity of antibodies in the immune deposits responsible for glomerular damage and dysfunction in these cases is at present uncertain. Calcineurin inhibitors (cyclosporine and tacrolimus) induce downregulation of a series of cytokines synthesised by T helper cells (Th1 and Th2) and antigenpresenting cells, particularly interleukin 2, which amongst other functions is involved in the activation of B lymphocytes and the subsequent production of antibodies 21 . This would be the key mechanism Table 3. Value of the relative reduction in the level of anti-PLA2R antibodies in relation to the baseline level in the 6, 9 and 12 month remission prediction A Value of the relative reduction in the anti-PLA2R antibody titre after 3 months in the 6, 9 and 12-month remission prediction Remission time Value Sensitivity % Specificity % ABC P 6 months 35% 87 93 0.98±0.01 0.000 9 months 30% 86 85 0.92±0.04 0.000 12 months 29% 60 70 0.71±0.08 0.004 B Value of the relative reduction in the anti-PLA2R antibody titre after 6 months in the 9 and 12-month remission prediction Remission time Value Sensitivity% Specificity % ABC P 9 months 50% 93 95 0.97±0.02 0.000 12 months 45% 87 98 0.96±0.02 0.000 496 Nefrologia 2014;34(4):491-7 Alfons Segarra-Medrano et al. Anti-PLA2R titre and evolution of IMN through which calcineurin inhibitor therapy induces the reduction observed in the anti-PLA2R titres and its correlation with remission. In summary, our data indicate that in patients with IMN, the reduction slope in the anti-PLA2R antibody titre is significantly associated with the time until evidence of remission. Furthermore, the relative reduction in the antiPLA2R antibody titre after 3 months is very sensitive and specific for predicting the response after 6 and 9 months, but not after 12 months, while the relative reduction in the antibody titre after 6 months has a high sensitivity and specificity for predicting the response after 9 and 12 months. These data may be useful in the clinical follow-up of patients after the start of therapy and they may be particularly important in cases in which, as has been recently proposed22,23, we consider the anti-PLA2R antibody titre as the base for treatment decisions. Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. REFERENCES 1. Donadio JV, Torres VE, Velosa JA, Wagoner RD, Holley KE, Okamura M, et al. Idiopathic membranous nephropathy. Kidney Int 1988;33:708-15. 2. Kerjaschki D. Pathomechanisms and molecular basis of membranous glomerulopathy. Lancet 2004;364:1194-6. 3. Fulladosa X, Praga M, Segarra A, Martínez Ara J. Glomerulonefritis membranosa. Nefrologia 2007;27(Suppl 2):70-86. 4. KDIGO Clinical Practice Guideline for glomerulonephritis idiopathic membranous nephropathy. Kidney Int Suppl 2012;2:186-97. 5. Donadio JV, Holley KE, Andersons CF, Taylor WF. Controlled trial of cyclophosphamide in idiopathic membranous nephropathy. Kidney Int 1974;6:431-9. 6. Ponticelli C, Zucchelli P, Passerini P, Cesana B, Locatelli F, Pasquali S, et al. A 10-year follow-up of a randomized study with methylprednisolone and chlorambucil in membranous nephropathy. Kidney Int 1995;48:1600-4. 7. Ponticelli C, Altieri P, Scolari F, Passerini P, Roccatello D, Cesana B, et al. A randomized study comparing methylprednisolone plus chlorambucil versus methylprednisolone plus cyclophosphamide in idiopathic membranous nephropathy. J Am Soc Nephrol 1998;9:44450. 8. Jha V, Ganguli A, Saha TK, Kohli HS, Sud K, Gupta KL, et al. A randomized, controlled trial of steroids and cyclophosphamide in adults with nephrotic syndrome caused by idiopathic membranous nephropathy. J Am Soc Nephrol 2007;18:1899-904. originals 9. Hofstra JM, Branten AJ, Wirtz JJ, Noordzij TC, du Buf-Vereijken PW, Wetzels JF. Early versus late start of immunosuppressive therapy in idiopathic membranous nephropathy: a randomized controlled trial. Nephrol Dial Transplant 2010;25:129-36. 10. van den Brand JA, van Dijk PR, Hofstra JM, Wetzels JF. Long-term outcomes in idiopathic membranous nephropathy using a restrictive treatment strategy. J Am Soc Nephrol 2014;25:150-8. 11. Cattran DC, Greenwood C, Ritchie S, Bernstein K, Churchill DN, Clark WF, et al. A controlled trial of cyclosporine in patients with progressive membranous nephropathy. Kidney Int 1995;47:1130-5. 12. Cattran DC, Appel GB, Hebert LA, Hunsicker LG, Pohl MA, Hoy WE, et al. Cyclosporine in patients with steroid resistant membranous nephropathy: A randomized trial. Kidney Int 2001;59:1484-90. 13. Praga M, Barrio V, Juárez GF, Luño J; Grupo Español de Estudio de la Nefropatía Membranosa. Tacrolimus monotherapy in membranous nephropathy: a randomized controlled trial. Kidney Int 2007;71:92430. 14.Beck LH Jr, Bonegio RG, Lambeau G, Beck DM, Powell DW, Cummins TD, et al. M-type phospholipase A2 receptor as target antigen in idiopathic membranous nephropathy. N Engl J Med 2009;361:1121. 15. Qin W, Beck LH Jr, Zeng C, Chen Z, Li S, Zuo K, et al. Anti-phospholipase A2 receptor antibody in membranous nephropathy. J Am Soc Nephrol 2011;22:1137-43. 16.Hoxha E, Harendza S, Zahner G, Panzer U, Steinmetz O, Fechner K, et al. An immunofluorescence test for phospholipase-A2-receptor antibodies and its clinical usefulness in patients with membranous glomerulonephritis. Nephrol Dial Transplant 2011;26:2526-32. 17.Hofstra JM, Beck LH Jr, Beck DM, Wetzels JF, Salant DJ. Anti-phospholipase A receptor antibodies correlate with clinical status in idiopathic membranous nephropathy. Clin J Am Soc Nephrol 2011;6:1286-91. 18.Kanigicherla D, Gummadova J, McKenzie EA, Roberts SA, Harris S, Nikam M, et al. Anti-PLA2R antibodies measured by ELISA predict long-term outcome in a prevalent population of patients with idiopathic membranous nephropathy. Kidney Int 2013;83:940-8. 19.Beck LH Jr, Fervenza FC, Beck DM, Bonegio RG, Malik FA, Erickson SB, et al. Rituximab-induced depletion of anti-PLA2R autoantibodies predicts response in membranous nephropathy. J Am Soc Nephrol 2011;22:1543-50. 20. Bomback AS, Derebail VK, McGregor JG, Kshirsagar AV, Falk RJ, Nachman PH. Rituximab therapy for membranous nephropathy: a systematic review. Clin J Am Soc Nephrol 2009;4:734-44. 21. Cattran DC, Alexopoulos E, Heering P, Hoyer PF, Johnston A, Meyrier A, et al. Cyclosporin in idiopathic glomerular disease associated with the nephrotic syndrome: Workshop recommendations. Kidney Int 2007;72:1429-47. 22.Hofstra JM, Wetzels JF. Anti-PLA2R antibodies in membranous nephropathy: ready for routine clinical practice? Neth J Med 2012;70:109-13. 23. Hofstra JM, Fervenza FC, Wetzels JF. Treatment of idiopathic membranous nephropathy. Nat Rev Nephrol 2013;9:443-58. Sent to review: 18 Mar. 2014 | Accepted: 3 Jun. 2014 Nefrologia 2014;34(4):491-7 497 http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society review Defining protein-energy wasting syndrome in chronic kidney disease: prevalence and clinical implications Carolina Gracia-Iguacel1, Emilio González-Parra2, Guillermina Barril-Cuadrado3, Rosa Sánchez4, Jesús Egido2, Alberto Ortiz-Arduán2, Juan J. Carrero5 1 Servicio de Nefrología. IIS-Fundación Jiménez Díaz. En el Centro Santa Engracia. Fundación Íñigo Álvarez de Toledo. Madrid (Spain); 2 Servicio de Nefrología. IIS-Fundación Jiménez Díaz. Universidad Autónoma de Madrid (Spain); 3 Servicio de Nefrología. Hospital Universitario de la Princesa. Madrid (Spain); 4 Servicio de Nefrología. Hospital de Segovia (Spain); 5 Servicio de Nefrología. Karolinska Institutet. Estocolmo (Sweeden) Nefrologia 2014;34(4):507-19 doi:10.3265/Nefrologia.pre2014.Apr.12522 ABSTRACT The presence of malnutrition in chronic kidney disease (CKD) is well-known. The discovery in the last 15 years of pathophysiological mechanisms that lead to this process, such as anorexia, the increase of protein catabolism and inflammation, has created the need for a new name by the International Society of Renal Nutrition and Metabolism (ISRNM): protein-energy wasting syndrome (PEW). This document’s objectives are to propose the use of the term “desgaste proteico energético” (DPE) as a more accurate translation of the English term and to update the pathogenic mechanisms involved that are inherent to DPE (PEW). We simultaneously review the latest epidemiological evidence that highlight the relevance of malnutrition and its impact both on mortality and morbidity in CKD. Finally, we point out the need to redefine DPE (PEW) diagnostic criteria so that they are applicable to the Spanish population with CKD. We do not think that the criteria established by the ISRNM can be extrapolated to different populations, as is the case, for example, with interracial anthropometric differences. Keywords: Protein-energy wasting syndrome. Chronic kidney disease. Correspondence: Carolina Gracia Iguacel Servicio de Nefrología. IIS-Fundación Jiménez Díaz. En el Centro Santa Engracia. Fundación Íñigo Álvarez de Toledo. Madrid (Spain). [email protected] Definiendo el síndrome de desgaste proteico energético en la enfermedad renal crónica: prevalencia e implicaciones clínicas RESUMEN La presencia de malnutrición es bien conocida en la enfermedad renal crónica (ERC). El descubrimiento en los últimos 15 años de los mecanismos fisiopatológicos que desencadenan este proceso, tales como la anorexia, el aumento del catabolismo proteico y la inflamación, ha generado la necesidad de una nueva denominación por la Sociedad Renal Internacional de Nutrición y Metabolismo (ISRNM): protein energy wasting syndrome (PEW). Los objetivos de este documento son proponer la utilización del término «desgaste proteico energético» (DPE) como una traducción más fiel del término anglosajón y actualizar los mecanismos patogénicos implicados que son inherentes al DPE. Simultáneamente revisamos las últimas evidencias epidemiológicas que ponen de manifiesto la relevancia de la malnutrición y su impacto tanto en la mortalidad como en la morbilidad en la ERC. Por último, destacamos la necesidad de redefinir los criterios diagnósticos del DPE para que sean aplicables a la población española con ERC. Los criterios establecidos por la ISRNM creemos que no son extrapolables a diferentes poblaciones, como ocurre por ejemplo con las diferencias antropométricas interraciales. Palabras clave: Síndrome de desgaste proteico-energético. Insuficiencia renal crónica. INTRODUCTION Chronic renal failure is characterised by nutritional disorders and systemic inflammation, which is accompanied by an increased catabolism, increasing 507 review morbidity and mortality. Nutritional disorders have been reported in the literature with numerous and confusing terms such as malnutrition, sarcopenia, cachexia and the malnutrition-inflammation-atherosclerosis syndrome. These terms describe a part of the problem but do not cover the many mechanisms that influence patient health and prognosis. In 2008, the International Society of Renal Nutrition and Metabolism (ISRNM) proposed that the term protein-energy wasting (PEW) be adopted as a unifying nomenclature and the starting point for a better knowledge and treatment of these problems in uraemic patients. The term PEW does not translate easily to Spanish and the Nutrition Working Group of the Spanish Society of Nephrology (S.E.N.) proposes to use the term “desgaste proteico energético” (DPE) as the most accurate translation of the English term. The PEW syndrome is very common in kidney patients and it causes a deterioration in their quality of life and decreases short-term survival. However, regrettably, many hospitals still do not incorporate measures to evaluate and monitor the nutritional state of patients. Likewise, adequate nutrition is a strategy that is sometimes forgotten in the management of kidney patients. We c a n d e f i n e t h e P E W s y n d r o m e a s a s i n g l e pathological condition in which purely nutritional disorders converge with catabolic conditions. Both are pathophysiologically related, they are enhanced by each other and they create a vicious circle, which makes it difficult to distinguish between the two components in clinical practice. A diagnostic and therapeutic approach in patients with PEW must be multifactorial and we must try to treat each and every factor that we can identify, since nutritional repletion is insufficient as the only treatment, as it does not slow down underlying proteolysis. With the intention of providing a current view of all catabolic disorders covered by the PEW syndrome, we reported the main concepts, mechanisms and implications of this state. Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD i.e., the disorders derived from the deficiency of macroand micronutrients2. By “undernourishment”, we mean a body composition disorder characterised by an excess of extracellular water, frequently associated with a decrease in muscle and fat tissue, hypoproteinaemia and potassium deficiency, which interferes with the normal response of the patient to their disease and treatment. “Protein-calorie undernourishment” is caused whenever daily needs are not covered by the diet. It is often reversed with the recovery of intake and the resolution of the underlying problem. Protein-calorie undernourishment can be divided into three main clinical syndromes: 1. Marasmus or calorie undernourishment: this develops gradually after months or years of insufficient energy intake. The patient appears cachexic, with a generalised loss of muscle mass and an absence of subcutaneous fat. The result is a generalised consumption syndrome (emaciation syndrome), with major weight loss, generally normal visceral protein reserves and a worsening of anthropometric measurements. 2. Kwashiorkor, protein or hypoalbuminaemic undernourishment: this begins and develops much quicker and it is regulated by hormones and cytokines, which act by decreasing organic visceral protein deposits. Cytokines such as interleukin (IL)-1 and tumour necrosis factor (TNF) mediate in the immune response of the patient to stress and cause changes in the acute phase reactants, such as fibrinogen at the expense of albumin. Decreased production, along with an exacerbated catabolism leads to marked hypoalbuminaemia. Recently, gut microbiota has been implicated in Kwashiorkor. 3. Mixed: very common in hospitalised patients. It usually occurs in previously undernourished subjects who suffer an intercurrent acute condition, causing protein-calorie undernourishment. CONCEPT AND TERMINOLOGY PEW 1 is defined as a pathological state where there is a continuous decrease or wasting of both protein deposits and energy reserves, including a loss of fat and muscle. Before introducing this new concept into our terminology, we should briefly consider the malnutritionundernourishment concept and its difference with other terms such as the wasting syndrome, in order to understand the unifying nature of the term PEW. The defining feature of undernourishment is weight loss. Survival during fasting is related to the already existing fat storage volume. Changes in body composition are reflected as a severe increase in extravascular water, a decrease in fat deposits and a decrease in lean body mass. It is important to highlight that weight may increase during a severe acute disease, due to fluids passing into the third space. Abnormalities in uraemia in a certain manner reflect mixed malnourishment, although it presents with a moderate intensity and is not the result of an intercurrent acute condition, but rather, a low-intensity chronic inflammation. The term “malnutrition” covers pathological states caused both by an excess and a deficiency of nutrients. However in uraemia, it is generally used to refer to undernourishment, The term “cachexia” represents a complex metabolic syndrome associated with a chronic disease and it is characterised by a gradual loss of muscle tissue, 508 Nefrologia 2014;34(4):507-19 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD accompanied or not by concomitant losses of fat reserves. Cachexia, however, represents an extreme degree of intake that is rarely observed in advanced chronic kidney disease (CKD). The term “wasting” was proposed by the World Health Organization in 1988 3 and is defined as an involuntary loss of weight of more than 10% on the baseline value in the absence of an opportunistic infection, a tumour disease or chronic diarrhoea. It is a multifactorial syndrome and it is occasionally difficult to know the main cause. It is characterised by a disproportionate loss of lean mass due to specific abnormalities in metabolism as part of the body’s defence mechanism in response to a stress situation. When this situation is sustained, it leads to a depletion of proteins, especially musculoskeletal proteins, and is not recovered with intake, since this whole process is due to cellular metabolic changes. It is very important to adopt common terminology is Spanish and we believe that the concept of DPE agreed on by the S.E.N. Nutrition Group accurately captures the spirit of the ISRNM’s nomenclature PEW. This term describes the mechanisms involved and consequently allows us to identify therapeutic targets, use the appropriate monitoring methods and choose the most effective therapeutic approach. We recognise that the term “wasting” is less clinically severe than “emaciation”, which may occur in patients with chronic kidney disease. However, in the choice of terms and acronyms, we must consider the advantage, using simpler language, of instilling in healthcare professionals the need to identify and treat these catabolic disorders. The terminology DPE avoids including terms such as malnutrition of catabolism, with the aim of not giving more importance to any one of the components. In these disorders, both undernourishment and muscle catabolism converge and are pathophysiologically related, and as such, it is impossible to distinguish one from the other in clinical practice. Therefore, DPE implies both accelerated protein (muscle) and energy (fat) loss. MECHANISMS INVOLVED IN PROTEIN-ENERGY WASTING The disorders involved in renal failure malnutrition have recently been revised by the ISRNM4. Anorexia5 and the increase in protein catabolism6 result in an energy imbalance, with the final result of an increase in energy wasting7 and in the intake of energy storage sources. Other pathophysiological mechanisms in CKD PEW are metabolic acidosis8, endocrine disorders9,10, inflammation11,12 and the activation of the ubiquitin-proteasome systems (UPS)13,14. At the same time, other aspects such as a restrictive Nefrologia 2014;34(4):507-19 review diet, the loss of amino acids and micro-macronutrients15 due to dialysis techniques, blood loss, volume overload16 and other psychosocial factors change the energy balance. Muscle mass loss (wasting) The term sarcopenia defines a situation of major loss of muscle mass and strength and a multifactorial aetiology, where an intake deficiency may occur, as well as hormonal disorders, neuropathic damage, metabolic disorders and the presence of uraemic toxins 17. It is a type of chronic muscular atrophy and in CKD, it is associated with PEW, limiting the independence of the patient and their quality of life. It compromises vital organs, with respiratory, musculoskeletal and heart muscle deterioration 18 . Decreased intake, metabolic acidosis, physical inactivity, diabetes and sepsis are associated factors in CKD that Table 1. Causes of developing protein-energy wasting in chronic kidney disease a) Decrease in intake and increase in loss of nutrients -Anorexia - Restrictive diets - Losses of amino acids in dialysis - Blood loss b) Increased catabolism - Metabolic acidosis - Endocrine disorders: insulin resistance, hypothyroidism, decreased testosterone levels, changes in growth hormone IGF1 - Inflammation, oxidative stress increase - Activation of proteolytic systems such as the ubiquitinproteasome and caspase systems - Accumulation of uraemic toxins - Activation of proinflammatory cytokines: IL-6, TNF-α (cachectin), IL-1 β, TGF-β - Increased energy wasting IIGF1: insulin-like growth factor 1; IL: interleukin; TGF: transforming growth factor; TNF: tumour necrosis factor. 509 review increase muscle proteolysis through increased catabolism, activation of different intracellular signals of muscle cell apoptosis and decreased synthesis. Several studies have shown significant atrophy of muscle fibres in CKD 19-21 (Table 1). One of the main mechanisms by which PEW is associated with muscle atrophy in uraemia is increased UPS-mediated protein catabolism and the activation of musculoskeletal myostatin. The UPS system degrades muscle proteins and myostatin is a member of the transforming growth factor β family, which inhibits cellular proliferation and muscle synthesis22. Intracellular activation of the caspase pathway and myostatin stimulate protein degradation, providing the substrate for the UPS and cell apoptosis. The extensive tissue damage leads to an increase in circulating actin, which may consume gelsolin (the protein that assembles and disassembles actin) and other proteins such as the vitamin D binding protein, which have a protective role23. High circulating actin and low circulating gelsolin levels in patients on haemodialysis are associated with an increased risk of mortality. Increased protein catabolism and an accumulation of uraemic toxins would alter gelsolin synthesis, leading to a loss in the ability to assemble actin, platelet activation, endothelial dysfunction and an increased susceptibility to infectious complications24. Another mechanism recently reported is resistance to insulin. Insulin-like growth factor 1 would activate the phosphoinositide 3-kinase pathway, altering protein metabolism and favouring an overregulation of myostatin with a decreased proliferation of satellite muscle cells25. PROTEIN-ENERGY WASTING DIAGNOSTIC CRITERIA PROPOSED BY THE INTERNATIONAL SOCIETY OF RENAL NUTRITION AND METABOLISM An important development is the consideration of the PEW syndrome as a single pathological condition in which undernourishment and hypercatabolism converge. An effective therapeutic approach to PEW cannot only be carried out by nutritional repletion, since this would not resolve proteolysis. A syndrome of a multifactorial origin requires diagnostic criteria and comprehensive therapy. The ISRNM has recommended diagnostic criteria (Table 2). It is necessary to fulfil at least one criterion in three of the four categories proposed (biochemical, body mass, muscle mass and intake criteria) 1 (Table 2). These criteria are initially attractive due to their multifactorial scope (analytical, anthropometric and nutritional), but when we try to apply them to clinical 510 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD practice, they become confusing. Leinig et al. 26 did not find any patient who had abnormalities in three of the four categories specified by the ISRNM and when the PEW syndrome was defined as abnormalities in two of the four sections, a prevalence of 17% was found, which is abnormally low if we compare it with the 65% prevalence when it is diagnosed by subjective global assessment (SGA). Another example of the questionable validity of these criteria is found in the study by Drechsler et al. 27, in which they analysed the relationship between PEW and cardiovascular mortality and mortality from other causes in a cohort of 1255 diabetic patients on regular haemodialysis. They observed that no patient fulfilled the PEW criteria proposed by the ISRNM. In this case, the authors redefined the ISRNM criteria, considering there to be PEW if the body mass index (BMI), albumin and serum creatinine were below the median in the patients studied. This article has limitations resulting from the Table 2. Diagnostic criteria for protein-energy wasting proposed by the International Society of Renal Nutrition and Metabolism1 Biochemical criteria Serum albumin <3.8g/dl (determined by bromocresol green) Prealbumin/transthyretin <30mg/dl (only for patients on dialysis) Serum cholesterol <100mg/dl Body mass Body mass index <23kg/m2 (except in some geographic areas) Non-intentional weight loss of >5% of weight in 3 months or >10% in 6 months Body fat <10% of body mass Muscle mass Muscle mass loss >5% in 3 months or >10 % in 6 months Decrease of the muscle area of the arms >10 % in relation to the 50th percentile of the reference population Generation/occurrence of creatinine Dietary intake Protein intake measured by the protein catabolism rate <0.8g/kg/day in dialysis or <0.6g/kg/day in patients with stages 2-5 CKD Calculated energy wasting <25kcal/kg/day for at least 2 months CKD: chronic kidney disease. Nefrologia 2014;34(4):507-19 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD fact that the whole study population was diabetic, with a consequential association with obesity, and as such, after the adjustments, there was a 16% prevalence of PEW. We believe that the ISRNM criteria have limitations that we must take into account. In prospective studies, these criteria should still demonstrate their superiority to other possible diagnostic combinations before their implementation becomes widespread. Recent observations illustrate this by suggesting, in a population of 570 patients on haemodialysis, that only the presence of hypoalbuminaemia had a similar or higher mortality prediction value than the sum of several malnutrition markers proposed by the ISRNM 28. However, we often forget that the prediction of mortality does not necessarily equate to a diagnosis of malnutrition, and the cut-off points suggested are often based on survival analysis. Secondly, the cut-off points of the parameters proposed derive from American populations, and this leads us to wonder whether or not they can be extrapolated to other geographic areas and lifestyles such as those of Europe, Asia, or in our case, Mediterranean countries. Thirdly, the dialysis population is increasingly older and it is difficult to separate the nutritional and body composition changes that occur with age from malnutrition resulting from uraemia. For these reasons, it is logical to think that the PEW diagnostic criteria in CKD must be adapted and altered in different demographic contexts (age, race), clinical situations (obesity, diabetes, moderate and advanced CKD, dialysis and transplantation) and contextual situations (lifestyle, geographic location and culture)29. In conclusion, although the criteria proposed by the ISRNM reinforce the complex nature of the PEW syndrome, they are based on tests/measurements that may be questionable individually-speaking 30 and, moreover, their diagnostic or prognostic validity have still not been demonstrated. However, we consider that highlighting, for the first time in this definition, the multifactorial nature of PEW and the need to use different complementary nutritional state markers has been an important step forward. PREVALENCE OF PROTEIN-ENERGY WASTING In the dialysis population, PEW traditionally has a wide prevalence of 18%-75% 26 . Without a doubt, the imprecision of these figures prevents us from drawing valid conclusions. One of the problems is the variety of assessment and monitoring tools and of cut-off points that have been used to obtain these figures. Hypoalbuminaemia has been defined in the literature with figures of <4, <3.8 or <3.5g/dl, with the added difficulty of its estimation being changed according to the methodology employed (bromocresol purple or bromocresol green). As such, we should not be surprised that prevalence varies to a Nefrologia 2014;34(4):507-19 review great extent with the methodology employed for its estimation. We are given an example of this by two studies in Brazil 26 and Europe 28. The prevalence of PEW varied between 23% and 74%, depending on whether it was defined by biochemical tools (albumin, creatinine), anthropometric tools (arm perimeter, BMI) or nutritional tools (SGA, energy/protein intake). The same occurs with other multi-centre studies, such as those carried out in the United States, in which a prevalence of 38% 31 has been reported. Lastly, and no less importantly, PEW prevalence in different countries is a reflection of the economic situation, the degree of development and the prevalence of malnutrition in the general population, making it impossible to refer to a general prevalence in the dialysis population. This also applies to prevalence in different regions, with varying resources, of the same city or country. In Spain, the first studies on the prevalence of malnutrition date back to 1994 and in 29 patients on chronic haemodialysis the nutritional state was analysed using anthropometric measurements such as the triceps skin fold, arm muscle circumference, BMI, visceral proteins (albumin), the normalised protein catabolic rate (nPCR) and protein intake 32. They observed that in a sizeable proportion of patients (65%), the reduction of fat and protein reserves was greater than that which the relative body weight indicated (only deficient in 38%). In the same year, the first and only tables of anthropometric parameters of a Spanish population on haemodialysis were published (761 patients) 33,34 . In the sample studied, prevalence of malnutrition defined according to anthropometric parameters and biochemical markers (albumin, transferrin, lymphocyte count) was 52% in males and 46% in females. The predictors of malnutrition were old age, comorbidity index, male sex, time on haemodialysis and nPCR. The multi-centre Dialysis Outcomes and Practice Pattern Study (DOPPS) displayed major differences between countries in the monitoring of nutritional parameters, with Spain being one of the most deficient in the recording of these parameters 35. As such, the nPCR was only recorded in 20% of dialysis units in Spain, compared with 90% in Germany and furthermore, there was only a nutritionist in 20% of units in Spain, compared with 85% in the United Kingdom. In contrast, there were no significant differences in the results of serum albumin (3.98g/dl), creatinine (9.1mg/dl) and BMI (23.9kg/m 2 ) with the other European countries. However, the prevalence of moderate malnutrition according to the SGA scale was lower in Spain that in other countries such as France (11% versus 18%). We must point out that the aforementioned studies included stable patients, and as such, there was a bias to eliminate critically or acutely ill patients, who probably had PEW. 511 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD review This leads us to believe that PEW prevalence may even be greater than that which we outline here. As such, in a recent analysis of our unit, we observed PEW prevalence, according to ISRNM criteria, of 37%, which increased to 41.1% when patients were followed up for two years36. Although the sample size was relatively small, the study included all patients in the dialysis unit (without exclusions) and we used all the ISRNM PEW criteria. The latest S.E.N. advanced CKD nutrition guidelines published in 200837 recommend assessing the nutritional state using nutritional, biochemical, anthropometric and proteinenergy intake tests. CLINICAL IMPLICATIONS The mortality rate of CKD patients, particularly cardiovascular mortality, is higher than in the general population 38-41. This high mortality rate persists in spite of correcting traditional cardiovascular factors, such as hypotension, dyslipidaemia, left ventricular hypertrophy and improving dialysis techniques 42 . PEW may be considered a new risk factor, underlying the phenomenon of reverse epidemiology, where markers that in the general population are associated with a lower probability of cardiovascular events, such a decreased BMI or low cholesterol levels, are associated with a higher presence of cardiovascular disease and lower survival in dialysis patients43. The presence of PEW in renal patients leads to the activation of compensatory mechanisms and the deregulation of others, which affects different organs and systems, including the immune, endocrine, musculoskeletal, adipose tissue, haematopoietic and gastrointestinal systems and causes poor adaptation to the inflammatory cascade activation44,45, leading to an increase in overall mortality (Table 3). Protein-energy wasting and cardiovascular mortality In patients with advanced CKD, malnutrition and the presence of PEW are significantly related to cardiovascular mortality 46,47 . Nutrients are necessary for the body to function correctly. Dietary restrictions in uraemic patients that limit potassium, phosphorus or sodium intake, amongst others, may lead to deficiencies of other essential nutrients if there is no dietary advice from healthcare staff. Essential nutrients are necessary for tissue synthesis and energy production, whilst being coenzymes in most enzymatic reactions in the body. Specific nutritional deficiencies, such as selenium, magnesium or vitamin D deficiencies, so common in kidney patients, have negative consequences on the antioxidant and anti-inflammatory capacity and on mineral and bone metabolism. As such, PEW is associated with a higher risk of infection and death due to infectious causes29,48. Deficiency of vitamins A, K and D is associated with greater cardiovascular mortality in haemodialysis patients 49,50. Up to 80% of haemodialysis Table 3. Underlying clinical impacts of the protein-energy wasting syndrome that lead to higher mortality Presence of protein energy wasting Clinical implications Nutritional: deficiency of micronutrients, vitamins (D, A, K), selenium and magnesium. Increased oxidative stress, endothelial dysfunction, increased vascular calcification Cardiovascular mortality Immune system: immune response disorder, with increased susceptibility to infections and a delay in the healing of wounds Inflammation and infection Endocrine system: hypothyroidism, insulin resistance. Decreased production of anti-inflammatory cytokines and adiponectins. Increase in advanced glycosylation products Inflammation and infection Activation of pro-inflammatory cytokines: CRP, IL-6, IL-1. Endothelial dysfunction and acceleration of the atherogenic process Mortality-reverse epidemiology Sarcopenia: increased actin levels. Muscle weakness, musculoskeletal system disorder Decreased quality of life. Increased hospitalisation CRP: C-reactive protein, IL: interleukin. 512 Nefrologia 2014;34(4):507-19 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD patients have a vitamin K deficiency due to insufficient intake (140µg/day versus 200µg/day in healthy patients). Subclinical hepatic vitamin K deficiency increases vitamin K-dependent non-carboxylated inactive proteins and may contribute to an increased risk of bone fractures and vascular calcification. Vitamin K supplements (menaquinone-7) decrease non-carboxylated proteins in haemodialysis patients and prolonged treatment can increase vascular elasticity51-53. PEW promotes increased muscle catabolism in uraemic patients, both due to the lack of circulating nutrients and due to the combined effect of systemic inflammation, metabolic acidosis, uraemic toxins and other factors. The result is a loss of muscle mass, which also affects the muscle tissue of the arteries and heart, with direct associations being found between malnutrition, arterial stiffness and abnormalities in myocardial structure. Continuous vascular distension resulting from salt and water overload aggravates this process and promotes ventricular hypertrophy. An example of how pure undernourishment leads to cardiovascular system abnormalities is found in the Minnesota experiment, conducted in 1944 during World War II. The aim was to better understand the pathophysiology of the undernourishment to which the Jews were subjected in the concentration camps. 36 volunteers underwent a controlled reduction in intake that resulted in a total loss of 25% of their weight. Undernourishment caused a decrease in cardiac volume of 17%, with reduced cardiac output, bradycardia, hypotension, and a decrease in peripheral oxygenation and in myocardial contractility54. Hypoalbuminaemia is the most common and most frequently used biomarker for measuring PEW in dialysis and it is a powerful prognostic marker of morbidity and mortality 55,56. Furthermore, hypoalbuminaemia has been associated with the de novo development and recurrence of congestive heart failure in patients on haemodialysis and peritoneal dialysis 57. In the 4D study carried out in a cohort of 1255 diabetic haemodialysis patients, we investigated the effect of PEW on mortality after four years. The presence of PEW (defined as BMI 26.7kg/ m 2 , serum albumin <3.8g/dl and creatinine <6.8mg/ dl) doubled the risk of overall mortality, death due to infections and sudden death of cardiac origin, but it was not related to a higher incidence of heart attacks. The presence of non-arteriosclerotic cardiovascular disease in this study was greater in patients with PEW as a cause of the cardiovascular events27. The hormonal abnormalities associated with uraemia, such as subclinical hypothyroidism 58 or low T3 syndrome 59 , are associated with inflammation and malnutrition 60 and may contribute to cardiovascular disease. As such, an independent association has been Nefrologia 2014;34(4):507-19 review observed between hypothyroidism and cardiovascular mortality in haemodialysis patients61,62. In patients with subclinical hypothyroidism and failure, the administration of synthetic T3 improved the neuroendocrine profile, with a significant decrease in levels of norepinephrine and B-type natriuretic peptide (pro-BNP) compared to the placebo. Furthermore, we observed an increase in diastolic volume of the left ventricle with increased cardiac output, without observing an increase in preload63. The decreased synthesis of other anabolic hormones such as testosterone 64 is also associated with greater muscle loss 65, endothelial dysfunction 66, anaemia, resistance to erythropoietin67 and mortality68. PROTEIN-ENERGY WASTING, INFECTION AND HOSPITALISATION Uraemia is considered to be acquired immunodeficiency state69 and patients with CKD have a high risk of infection70. In the HEMO study, infection was the first cause of death (23%) and the risk of death associated with an infection during hospitalisation was 15%. The factors that predispose CKD patients to infection according to the HEMO study were old age, hypoalbuminaemia, immunosuppressive therapy and catheters as vascular access 71. In parallel, in the DOPPS 29 study, infection was the cause of 55% of death in haemodialysis patients and it was related to hypoalbuminaemia, low nPCR and cachexia. The definition of the malnutrition status according to the concept of PEW leads to a deficiency of the immune system and an abnormal response in the patient, and as such, it is associated with greater susceptibility to infections and a slow recovery from injuries 72. The deficiency of certain micro-macronutrients favours a state of immunodeficiency. Some amino acids such as arginine and glutamine act and favour the immune response 73. A severe zinc, vitamin B6 (pyridoxine), vitamin C and folic acid deficiency 74-76 alters the immune response, decreases the production of antibodies, causes polymorphonuclear leukocyte or lymphocyte dysfunction and delays the scarring and curing of injuries. Haemodialysis patients with PEW are exposed to a greater risk of infection and its complications, increasing mortality 77. For example, in infection by the hepatitis C virus, the presence of hypoalbuminaemia and a high result in the MIS (malnutrition inflammation score) scale is independently associated with active infection and increased viral replication78. In hospitalised patients, a deficient nutritional state delays recovery, prolongs hospitalisation, increases the rate of infections and re-admissions and increases dependency upon discharge and the need for institutionalisation. In dialysis patients with prolonged and complicated hospitalisation, there is a rapid decrease in albumin and 513 review weight loss, particularly in those who have previously been undernourished, elderly patients and those with comorbidities and anorexia 79. The recommendations of the guidelines on the prevention and management of hospital undernourishment may be useful in hospitalised patients with CKD, since they include the use of supplements and parenteral nutrition to improve the nutritional situation 80. PROTEIN-ENERGY WASTING AND INFLAMMATION Several studies have observed an independent association between inflammatory conditions, commonly measured by an increase in C-reactive protein (CRP), IL6, IL1 and TNF-α, with the risk of cardiovascular mortality in haemodialysis patients81 and in the general population82. Inflammation is associated with both anorexia and an increased protein catabolism 83,84 and it seems to be the connection that explains the relationship between PEW and mortality in CKD. The relationship between malnutrition and inflammation in patients with CKD may be one of the causes of mortality associated with malnutrition. Moreover, PEW may also be the result of chronic inflammatory states in patients with renal failure85,86. PROTEIN-ENERGY WASTING AND QUALITY OF LIFE An aspect that is sometimes underappreciated by nephrologists, but which is increasingly important in clinical practice, is the impact of nursing on the degree of patient functionality. The impact of CKD on overall patient functioning can be recorded in quality of life surveys such as PROs (patient-reported outcomes) and Qo1 (health related quality of life) surveys, which assess the mental and functional state of the patient. CKD is associated with a poor QoL and this leads to a higher risk of mortality87. QoL has also been related to malnutrition markers, where worse values for QoL are associated with low levels of albumin, plasma creatinine, loss of LBM (lean tissue, mainly muscle tissue) and a high percentage of fat88. An improved QoL has become one of the objectives in dialysis patients. The prevalence of mental states of depression and anxiety is high in dialysis patients 89. They face situations such as hospitalisation, anxiety due to changes in dialysis, dietary and water restrictions and the adaptation of dialysis to their daily lives. The fear of inability, disability and a lower life expectancy are at the heart of these changes in frame of mind. New methods and tools are being developed to measure depression and 514 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD anxiety and it has been acknowledged that anxiety is under-diagnosed 90. REVERSE EPIDEMIOLOGY IN RENAL FAILURE: IMPLICATIONS OF NUTRITIONAL STATE In the evaluation of morbidity and mortality risk factors in CKD patients, we often observe paradoxically opposed trends to those observed in the general population. A clear example is obesity, which in observational studies, appears to be a protective factor against mortality in the final stages of CKD. This is what is known as the reverse or paradoxical epidemiology uraemic obesity phenomenon. The cause of these reverse epidemiology phenomena is the devastating effect that PEW has on short-term survival, which does not leave enough time for other traditional risk factors to act in long-term mortality 91 . The most striking examples of this include the case of hypercholesterolaemia, which has a reverse association with mortality in uraemic patients. When patients are divided according to whether they do or do not have PEW, we observe that in the presence of PEW, hypercholesterolaemia is a protective factor, while in the absence of PEW, it is a risk factor. In a situation of energy consumption affecting the patient, cholesterol temporarily becomes a marker of the body’s fat reserves, and when there is more fat, the patient can resist this energy consumption for longer. The same reasoning applies to the paradox of obesity. Dialysis patients, independently of the method used, have an inversely proportionate relationship between BMI and mortality 92, differing from the general population, in which this relationship is U-shaped (both extremes, malnutrition and obesity have increased mortality)93. In this instance, obesity involves an excess energy state that helps patients resist PEW. However, long-term obesity is a risk factor related to inflammation, atherosclerosis and calcification, for example94. This is due to the endocrine nature of adipocytes and the ability to regulate these processes by cytokine and adipocytokine secretion 95 . Endocrinologically active fat, fundamentally that which accumulates in the abdomen, promotes these processes. As such, the amount of total fat (reflection of the health of energy reserves) and abdominal fat (participating in obesity-associated risk) may have opposite effects on patient risk96. Another explanation of the reverse epidemiology of BMI in uraemia is the inability of the BMI to distinguish between muscle mass, body fat distribution (abdominal versus peripheral) and hypervolaemia. Therefore, we were recently able to observe that a BMI >30kg/m 2 was not capable of distinguishing excess body fat in 65% Nefrologia 2014;34(4):507-19 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD of dialysis patients 43. Recent studies highlight that the type and distribution of fat, more than the total fat, is a determining factor of risk97. Specifically, the accumulation of abdominal fat is a risk factor and is associated with greater secretion of pro-inflammatory adiponectins 98 . It has been reported that both leptin and visfatin are activators of cardiovascular disease and are endothelial dysfunction risk factors 99,100. Observational studies based on creatinine kinetics suggest that the protective effect of BMI in haemodialysis patients is due to its indication of greater muscle mass 101. In dialysis patients, it is perhaps necessary to conserve both tissues, fat and muscle. In this respect, a low arm muscle circumference percentile as an indicator of muscle mass and a low triceps skin fold as an indicator of fat tissue are related in equal measure to higher mortality in haemodialysis patients 102. Lastly, the risk of mortality increases whenever BMI, creatinine and weight progressively decrease, but if weight decreases and creatinine increases, the risk of mortality is reduced 103. CONCLUSION The term protein-energy wasting or PEW attempts to unite in one sole pathological condition the many nutritional and catabolic disorders that occur in CKD and which lead to a gradual and progressive loss of both muscle and fat mass. It is a common syndrome, particularly from stage 4-5 CKD, which is present in 30%-60% of dialysis patients. The clinical consequences of PEW may be severe and require rapid and effective treatment, since it is associated with increased overall and cardiovascular mortality, an increased number of review infections and admissions and many other comorbidities. The devastating effect of PEW causes paradoxical epidemiologies that are explained by competition between short- and long-term risk factors. Acknowledgements ISCIII-RETIC REDinREN/RD06/0016 and 12/0021, PIE13/00051, Spanish Society of Nephrology, Swedish Research Council, Research Activity Intensification programme (ISCIII). Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. REFERENCES 1. Fouque D, Kalantar-Zadeh K, Kopple J, Cano N, Chauveau P, Cuppari L, et al. A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease. Kidney Int 2008;73:391-8. 2. Polo R, José Galindo M, Martínez E, Alvarez J, Arévalo JM, Asensi V, et al.; Study Group for Metabolic Alterations/ S e c re t a r i a t f o r t h e N a t i o n a l A I D S P l a n ( G E A M / S P N S ) . [ R e c o m m e n d a t i o n s o f t h e S t u d y G ro u p f o r M e t a b o l i c Alterations/Secretariat for the National AIDS Plan (GEAM/ SPNS) on the management of metabolic and morphologic alterations in patients with HIV infection]. Enferm Infecc Microbiol Clin 2006;24:96-117. KEY CONCEPTS 1. Protein-energy wasting is defined as a pathological state where there is a continuous decrease or wasting of both protein deposits and energy reserves. 2. The pathophysiological mechanisms involved in PEW are anorexia and increased protein catabolism, which lead to an energy imbalance, with the final result of increased energy wasting. 3. For a correct diagnosis of PEW, we require the assessment of biochemical and body composition Nefrologia 2014;34(4):507-19 markers and a calculation of muscle loss and dietary intake. 4. The presence of PEW is associated with an increased cardiovascular risk, a risk of infection, hospitalisation and mortality, inflammation and a decreased quality of life. 5. The presence of PEW is explained by the known reverse epidemiology phenomenon, in which traditional risk factors appear as protection factors. 515 review 3. Gorstein J, Akré J. The use of anthropometry to assess nutritional status. World Health Stat Q 1988;41(2):48-58. 4. Carrero JJ, Stenvinkel P, Cuppari L, Ikizler TA, KalantarZadeh K, Kaysen G, et al. Etiology of the protein-energy wasting syndrome in chronic kidney disease: a consensus statement from the International Society of Renal Nutrition and Metabolism (ISRNM). J Ren Nutr 2013;23:77-90. 5. Carrero JJ, Qureshi AR, Axelsson J, Avesani CM, Suliman ME, Kato S, et al. Comparison of nutritional and inflammatory markers in dialysis patients with reduced appetite. Am J Clin Nutr 2007;85:695-701. 6. Carrero JJ, Chmielewski M, Axelsson J, Snaedal S, Heimbürger O, Bárány P, et al. Muscle atrophy, inflammation and clinical outcome in incident and prevalent dialysis patients. Clin Nutr 2008;27:55764. 7. Avesani CM, Draibe SA, Kamimura MA, Dalboni MA, Colugnati FA, Cuppari L. Decreased resting energy expenditure in nondialysed chronic kidney disease patients. Nephrol Dial Transplant 2004;19:3091-7. 8. Kalantar-Zadeh K, Mehrotra R, Fouque D, Kopple JD. Metabolic acidosis and malnutrition–inflammation complex syndrome in chronic renal failure. Semin Dial 2004;17:455-65. 9. Ros S, Carrero JJ. Endocrine alterations and cardiovascular risk in CKD: is there a link? Nefrologia 2013;33:181-7. 10. Gohda T, Gotoh H, Tanimoto M, Sato M, Io H, Kaneko K, et al. Relationship between abdominal fat accumulation and insulin resistance in hemodialysis patients. Hypertens Res 2008;31:83-8. 11. Carrero JJ, Park SH, Axelsson J, Lindholm B, Stenvinkel P. Cytokines, atherogenesis, and hypercatabolism in chronic kidney disease: a dreadful triad. Semin Dial 2009;22:381-6. 12. Vesani CM, Carrero JJ, Axelsson J, Qureshi AR, Lindholm B, Stenvinkel P. Inflammation and wasting in chronic kidney disease: Partners in crime. Kidney Int 2006;70:S8-13. 13. Mitch WE, Medina R, Grieber S, May RC, England BK, Price SR, et al. Metabolic acidosis stimulates muscle protein degradation by activating the adenosine triphophate dependent pathways involving ubiquitin and proteasomes. J Clin Invest 1994;93:212733. 14. Mitch WE. Proteolytic mechanisms, not malnutrition, cause loss of muscle mass in kidney failure. J Ren Nutr 2006;16:208-11. 15. Ikizler TA, Flakoll PJ, Parker RA, Hakim RM. Amino acid and albumin losses during hemodialysis. Kidney Int 1994;46:830-7. 16. Jacobs LH, van de Kerkhof JJ, Mingels AM, Passos VL, Kleijnen VW, Mazairac AH, et al. Inflammation, overhydration and cardiac biomarkers in haemodialysis patients: a longitudinal study. Nephrol Dial Transplant 2010;25:243-8. 17. Ikizler TA, Cano NJ, Franch H, Fouque D, Himmelfarb J, KalantarZadeh K, et al. Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism. Kidney Int 2013;84:1096-107. 18. Muscaritoli M, Anker SD, Argilés J, Aversa Z, Bauer JM, Biolo G, et al. Consensus definition of sarcopenia, cachexia and pre-cachexia: joint document elaborated by Special Interest Groups (SIG) “cachexia-anorexia in chronic wasting diseases” and “nutrition in geriatrics”. Clin Nutr 2010;29:154-9. 516 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD 19. Lim VS, Kopple JD. Protein metabolism in patients with chronic renal failure: role of uremia and dialysis. Kidney Int 2000;58:1-10. 20.Mitch WE. Malnutrition: a frequent misdiagnosis for hemodialysis patients. J Clin Invest 2002;110:437-9. 21.Stenvinkel P, Heimbürger O, Lindholm B. Wasting, but not malnutrition, predicts cardiovascular mortality in end stage renal disease. Nephrol Dial Transplant 2004;19:2181-3. 22. Mitch WE, Goldberg AL. Mechanisms of muscle wasting. The role of the ubiquitin-proteasome pathway. N Engl J Med 1996;335:1897905. 23. Zhang L, Rajan V, Lin E, Hu Z, Han HQ, Zhou X, et al. Pharmacological inhibition of myostatin suppresses systemic inflammation and muscle atrophy in mice with chronic kidney disease. FASEB J 2011;25:1653-63. 24. Lee PS, Sampath K, Karumanchi SA, Tamez H, Bhan I, Isakova T, et al. Plasma gelsolin and circulating actin correlate with hemodialysis mortality. J Am Soc Nephrol 2009;20:1140-8. 25.Zhang L, Wang XH, Wang H, Du J, Mitch WE. Satellite cell dysfunction and impaired IGF-1 signaling cause CKD-induced muscle atrophy. J Am Soc Nephrol 2010;21:419-27. 26. Leinig CE, Moraes T, Ribeiro S, Riella MC, Olandoski M, Martins C, et al. Predictive value of malnutrition markers for mortality in peritoneal dialysis patients. J Ren Nutr 2011;21:176-83. 27. D rechsler C, Grootendorst DC, Pilz S, Tomaschitz A, Krane V, Dekker F, et al. Wasting and sudden cardiac death in hemodialysis patients: a post hoc analysis of 4D (Die Deutsche Diabetes Dialyse Studie). Am J Kidney Dis 2011;58:599-607. 28. Mazairac AH, de Wit GA, Grooteman MP, Penne EL, van der Weerd NC, van den Dorpel MA, et al. A composite score of protein-energy nutritional status predicts mortality in haemodialysis patients no better than its individual components. Nephrol Dial Transplant 2011;26:1962-7. 29. Lopes AA, Bragg-Gresham JL, Elder SJ, Ginsberg N, Goodkin DA, Pifer T, et al. Independent and joint associations of nutritional status indicators with mortality risk among chronic hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). J Ren Nutr 2010;20:224-34. 30. Leal VO, Moraes C, Stockler-Pinto MB, Lobo JC, Farage NE, Velarde LG, et al. Is a body mass index of 23 kg/m2 a reliable marker of protein-energy wasting in hemodialysis patients? Nutrition 2012;28:973-7. 31. Kalantar-Zadeh K, Block G, McAllister CJ, Humphreys MH, Kopple JD. Appetite and inflammation, nutrition, anemia, and clinical outcome in hemodialysis patients. Am J Clin Nutr 2004;80:299307. 32. Lorenzo V, de Bonis E, Hernández D, Rodríguez P, Rufino M, González Posada J, et al. Desnutrición calórica-proteica en hemodiálisis crónica. Utilidad y limitaciones de la tasa de catabolismo proteico. Nefrologia 1994;14(Suppl 2):119-25. 33. Marcén R, Teruel JL, de la Cal MA, Gámez C. The impact of malnutrition in morbidity and mortality in stable haemodialysis patients. Nephrol Dial Transplant 1997;12:2324-31. 34. Marcén R, Gámez C, y el grupo de Estudio Cooperativo de Nutrición en Hemodiálisis. Estudio cooperativo de nutrición en hemodiálisis V: Tablas de parámetros antropométricos de una población en hemodiálisis. Nefrologia 1994;14(Suppl 2):60-3. Nefrologia 2014;34(4):507-19 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD 35. Hecking E, Bragg-Gresham JL, Rayner HC, Pisoni RL, Andreucci VE, Combe C, et al. Haemodialysis prescription, adherence and nutritional indicators in five European countries: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS). Nephrol Dial Transplant 2004;19:100-7. 36. G racia-Iguacel C, González-Parra E, Pérez-Gómez MV, Mahíllo I, Egido J, Ortiz A, et al. Prevalence of protein-energy wasting syndrome and its association with mortality in haemodialysis patients in a centre in Spain. Nefrologia 2013;33:495-505. 37. Ruperto López M, Barril Cuadrado G, Lorenzo Sellares V. Guía de Nutrición en Enfermedad Renal Crónica Avanzada (ERCA). Nefrologia 2008;28 Suppl 3:79-86. 38. K eith DS, Nichols GA, Gullion CM, Brown JB, Smith DH. Longitudinal follow-up and outcomes among a population with chronic kidney disease in a large managed care organization. Arch Intern Med 2004;164:659-63. 39. Wen CP, Cheng TY, Tsai MK, Chang YC, Chan HT, Tsai SP, et al. All-cause mortality attributable to chronic kidney disease: a prospective cohort study based on 462 293 adults in Taiwan. Lancet 2008;371:2173-82. 40. Carrero JJ, de Jager DJ, Verduijn M, Ravani P, De Meester J, Heaf JG, et al. Cardiovascular and noncardiovascular mortality among men and women starting dialysis. Clin J Am Soc Nephrol 2011;6:172230. 41. G o AS, Chertow GM, Fan D, McCulloch CE, Hsu CY. Chronic kidney disease and the risks of death, cardiovascular events, and hospitalization. N Engl J Med 2004;351:1296-305. 42.Eknoyan G, Beck GJ, Cheung AK, Daugirdas JT, Greene T, Kusek JW, et al. Effect of dialysis dose and membrane flux in maintenance hemodialysis. N Engl J Med 2002;347:2010-9. 43. Gracia-Iguacel C, Qureshi AR, Avesani CM, Heimbürger O, Huang X, Lindholm B, et al. Subclinical versus overt obesity in dialysis patients: more than meets the eye. Nephrol Dial Transplant 2013;28 Suppl 4:iv175-81. 44. Kovesdy CP, Kalantar-Zadeh K. Why is protein energy wasting associated with mortality in chronic kidney disease? Semin Nephrol 2009;29:3-14. 45. Meuwese CL, Carrero JJ. Chronic kidney disease and hypothalamicpituitary-axis dysfunction: the chicken or the egg? Arch Med Res 2013;44(8):591-600. 46.Locatelli F, Manzoni C, Del Vecchio L, Di Filippo S. Changes in the clinical condition of haemodialysis patinets. J Nephrol 1999;12:S8291. 47.Kalantar-Zadeh K, Abbott KC, Kronenberg F, Anker SD, Horwich TB, Fonarow GC. Epidemiology of dialysis patients and heart failure patients. Semin Nephrol 2006;26:118-33. 48. Dong J, Li Y, Xu Y, Xu R. Daily protein intake and survival in patients on peritoneal dialysis. Nephrol Dial Transplant 2011;26:3715-21. 49. Kalousová M, Kubena AA, Kostírová M, Vinglerová M, Ing OM, Dusilová-Sulková S, et al. Lower retinol levels as an independent predictor of mortality in long-term hemodialysis patients: a prospective observational cohort study. Am J Kidney Dis 2010;56:513-21. 50. Gracia-Iguacel C, Gallar P, Qureshi AR, Ortega O, Mon C, Ortiz M, et al. Vitamin D deficiency in dialysis patients: effect of dialysis Nefrologia 2014;34(4):507-19 review modality and implications on outcome. J Ren Nutr 2010;20:35967. 51. C ranenburg E, Schurgers L, Uiterwijk H, Beulens J, Dalmeijer GW, Westerhuis R, et al. Vitamin K intake and status are low in hemodialysis patients. Kidney Int 2012;82:605-10. 52. Westenfeld R, Krueger T, Schlieper G, Cranenburg EC, Magdeleyns EJ, Heidenreich S, et al. Effect of vitamin K2 supplementation on functional vitamin K deficiency in hemodialysis patients: a randomized trial. Am J Kidney Dis 2012;59:186-95. 53. Theuwissen E, Smit E, Vermeer C. The role of vitamin K in soft tissue calcification. Adv Nutr 2012;3:166-73. 54. Keys A. Will you starve that they be better fed? Brochure dated May 27, 1944. 55. Kalantar-Zadeh K, Kilpatrick RD, Kuwae N. Revisiting mortality predictability of serum albumin in the dialysis population: time dependency, longitudinal changes and population-attributable fraction. Nephrol Dial Transplant 2005;2:1880-8. 56. Ikizler TA, Wingar RL, Harvell J, Shyr Y, Hakim RM. Association of morbidity with markers of nutrition and inflammation in chronic hemodialysis patients: A prospective study. Kidney Int 1999;55:1945-51. 57. Foley RN, Pafrey PS, Harnnett JD, Kent GM, Murray DC, Barre PE. Hypoalbuminemia, cardiac morbidity and mortality in end-stage renal disease. J Am Soc Nephrol 1996;7:728-36. 58.Lo JC, Chertow GM, Go AS, Hsu CY. Increased prevalence of subclinical and clinical hypothyroidism in persons with chronic kidney disease. Kidney Int 2005;67:1047-52. 59. M euwese CL, Dekkers OM, Stenvinkel P, Dekker FW, Carrero JJ. Nonthyroidal illness and the cardiorenal syndrome. Nat Rev Nephrol 2013;9:599-609. 60. Enia G, Panuccio V, Cutrupi S, Zoccali C. Subclinical hypothyroidism is linked to micro-inflammation and predicts death in continuous ambulatory peritoneal dialysis. Nephrol Dial Transplant 2007;22:538-44. 61. Carrero JJ, Qureshi AR, Axelsson J, Yilmaz MI, Rehnmark S, Witt MR, et al. Clinical and biochemical implications of low thyroid hormone levels (total and free forms) in euthyroid patients with chronic kidney disease. J Intern Med 2007;262:690-701. 62. Meuwese CL, Dekker FW, Lindholm B, Qureshi AR, Heimburger O, Barany P, et al. Baseline levels and trimestral variation of triiodothyronine and thyroxine and their association with mortality in maintenance hemodialysis patients. Clin J Am Soc Nephrol 2012;7:131-8. 63.Pingitore A, Galli E, Barison A, Iervasi A, Scarlattini M, Nucci D, et al. Acute effects of triiodothyronine (T3) replacement therapy in patients with chronic heart failure and low T3 syndrome: a randomized placebo-controlled study. J Clin Endocrinol Metab 2008;93:1351-8. 64. Carrero JJ, Stenvinkel P. The vulnerable man: impact of testosterone deficiency on the uraemic phenotype. Nephrol Dial Transplant 2012;27:4030-41. 65. Cigarrán S, Pousa M, Castro MJ, González B, Martínez A, Barril G, et al. Endogenous testosterone, muscle strength, and fat-free mass in men with chronic kidney disease. J Ren Nutr 2013;23:e89-95. 66. Yilmaz MI, Axelsson J, Sonmez A, Carrero JJ, Saglam M, Eyileten T, et al. Effect of renin angiotensin system blockade on pentraxin 517 review 3 levels in type-2 diabetic patients with proteinuria. Clin J Am Soc Nephrol 2009;4:535-41. 67. Carrero JJ, Qureshi AR, Nakashima A, Arver S, Parini P, Lindholm B,et al. Prevalence and clinical implications of testosterone deficiency in men with end-stage renal disease. Nephrol Dial Transplant 2011;26:184-90. 68. Miyamoto T, Carrero JJ, Qureshi AR, Anderstam B, Heimbürger O, Bárány P, et al. Circulating follistatin in patients with chronic kidney disease: implications for muscle strength, bone mineral density, inflammation, and survival. Clin J Am Soc Nephrol 2011;6:1001-8. 69. Vanholder R, Ringoir S. Infectious morbidity and defects of phagocytic function in end-stage renal disease: a review. J Am Soc Nephrol 1993;3:1541-54. 70. Dalrymple LS, Go AS. Epidemiology of acute infections among patients with chronic kidney disease. Clin J Am Soc Nephrol 2008;3:1487-93. 71. Allon M, Depner TA, Radeva M, Bailey J, Beddhu S, Butterly D, et al.; HEMO Study Group. Impact of dialysis dose and membrane on infection-related hospitalization and death: results of the HEMO Study. J Am Soc Nephrol 2003;14:1863-70. 72. Vanholder R, Dell’Aquila R, Jacobs V, Dhondt A, Veys N, Waterloss MA, et al. Depressed phagocytosis in hemodialyzed patients: in vivo and in vitro mechanisms. Nephron 1993;63:409-15. 73. H ulsewé KW, van Acker BA, von Meyenfeldt MF, Soeters PB. Nutritional depletion and dietary manipulation: effects on the immune response. World J Surg 1999;23:536-44. 74. Erten Y, Kayatas M, Sezer S, Ozdemir FN, Ozyiğit PF, Turan M, et al. Zinc deficiency: prevalence and causes in hemodialysis patients and effect on cellular immune response. Transplant Proc 1998;30:8501. 75. Casciato DA, McAdam LP, Kopple JD, Bluestone R, Goldberg LS, Clements PJ, et al. Immunologic abnormalities in hemodialysis patients: improvement after pyridoxine therapy. Nephron 1984;38:9-16. 76. D obbelstein H, Körner WF, Mempel W, Grosse-Wilde H, Edel HH. Vitamin B6 deficiency in uremia and its implications for the depression of immune responses. Kidney Int 1974;5:233-9. 77. Vanholder R, Van Loo A, Dhondt AM, De Smet R, Ringoir S. Influence of uraemia and haemodialysis on host defence and infection. Nephrol Dial Transplant 1996;11:593-8. 78. Kalantar-Zadeh K, Kilpatrick RD, McAllister CJ, Miller LG, Daar ES, Gjertson DW, et al. Hepatitis C virus and death risk in hemodialysis patients. J Am Soc Nephrol 2007;18:1584-93. 79. Borrego Utiel FJ, Segura Torres P, Pérez del Barrio MP, Sánchez Perales MC, García Cortés MJ, Serrano Angeles P, et al. Influencia de las patologías relacionadas con el ingreso hospitalario sobre el estado nutricional de los pacientes en hemodiálisis. Nefrologia 2011;31:471-83. 80. García de Lorenzo A, Álvarez Hernández J, Planas M, Burgos R, Araujo K; multidisciplinary consensus work-team on the approach to hospital malnutrition in Spain. Multidisciplinary consensus on the approach to hospital malnutrition in Spain. Nutr Hosp 2011;26:701-10. 81.Meuwese CL, Carrero JJ, Stenvinkel P. Recent insights in inflammation-associated wasting in patients with chronic kidney disease. Contrib Nephrol 2011;171:120-6. 82. Carrero JJ, Stenvinkel P. Inflammation in end-stage renal disease-518 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD what have we learned in 10 years? Semin Dial 2010;23:498-509. 83. Stenvinkel P, Ketteler M, Johnson RJ, Lindholm B, Pecoits-Filho R, Riella M, et al. IL10, IL6 and TNF alpha important factors in the altered cytokine network of end-stage renal disease- the good, the bad and the ugly. Kidney Int 2005;67:1216-33. 84. Bergström J, Lindholm B, Lacson E Jr, Owen W Jr, Lowrie EG, Glassock RJ, et al. What are the causes and consequences of the chronic inflammatory state in chronic dialysis patients? Semin Dial 2000;13:163-75. 85. Kalantar-Zadeh K, Kopple JD. Relative contributions of nutrition and inflammation to clinical outcome in dialysis patients. Am J Kidney Dis 2001;38:1343-50. 86. Qureshi AR, Alvestrand A, Divino Filho JC, Gutierrez A, Heimbürger O, Lindholm B, et al. Inflammation, malnutrition and cardiac disease as predictors of mortality in hemodialysis patients. J Am Soc Nephrol 2002;13 Suppl 1:S28-36. 87. Feroze U, Noori N, Kovesdy CP, Molnar MZ, Martin DJ, Reina-Patton A, et al. Quality-of-life and mortality in hemodialysis patients: roles of race and nutritional status. Clin J Am Soc Nephrol 2011;6:110011. 88. Mazairac AH, de Wit GA, Penne EL, van der Weerd NC, Grooteman MP, van den Dorpel MA, et al. Protein-energy nutritional status and kidney disease-specific quality of life in hemodialysis patients. J Ren Nutr 2011;21:376-386.e1. 89. Allen KL, Miskulin D, Yan G, Dwyer JT, Frydrych A, Leung J, et al.; Hemodialysis (HEMO) Study Group. Association of nutritional markers with physical and mental health status in prevalent hemodialysis patients from the HEMO study. J Ren Nutr 2002;12:160-9. 90. Feroze U, Martin D, Kalantar-Zadeh K, Kim JC, Reina-Patton A, Kopple JD. Anxiety and depression in maintenance dialysis patients: preliminary data of a cross-sectional study and brief literature review. J Ren Nutr 2012;22:207-10. 91. Chmielewski M, Carrero JJ, Qureshi AR, Axelsson J, Heimbürger O, Berglund L, et al. Temporal discrepancies in the association between the apoB/apoA-I ratio and mortality in incident dialysis patients. J Intern Med 2009;265:708-16. 92. Cabezas-Rodriguez I, Carrero JJ, Zoccali C, Qureshi AR, Ketteler M, Floege J, et al. Influence of body mass index on the association of weight changes with mortality in hemodialysis patients. Clin J Am Soc Nephrol 2013;8:1725-33. 93. Kalantar-Zadeh K, Block G, Humphreys MH, Kopple JD. Reverse epidemiology of cardiovascular risk factors in maintenance dialysis patients. Kidney Int 2003;63:793-808. 94. Cordeiro AC, Qureshi AR, Lindholm B, Amparo FC, Tito-PaladinoFilho A, Perini M, et al. Visceral fat and coronary artery calcification in patients with chronic kidney disease. Nephrol Dial Transplant 2013;28 Suppl 4:iv152-9. 95. Witasp A, Carrero JJ, Heimbürger O, Lindholm B, Hammarqvist F, Stenvinkel P, et al. Increased expression of pro-inflammatory genes in abdominal subcutaneous fat in advanced chronic kidney disease patients. J Intern Med 2011;269:410-9. 96. Carrero JJ, Cordeiro AC, Lindholm B, Stenvinkel P. The emerging pleiotrophic role of adipokines in the uremic phenotype. Curr Opin Nephrol Hypertens 2010;19:37-42. 97. Cordeiro AC, Qureshi AR, Stenvinkel P, Heimbürger O, Axelsson J, Nefrologia 2014;34(4):507-19 Carolina Gracia-Iguacel et al. Protein-energy wasting in CKD Bárány P, et al. Abdominal fat deposition is associated with increased inflammation, protein-energy wasting and worse outcome in patients undergoing haemodialysis. Nephrol Dial Transplant 2010;25:562-8. 98. Postorino M, Marino C, Tripepi G, Zoccali C; CREDIT (Calabria Registry of Dialysis and Transplantation) Working Group. Abdominal obesity and all-cause and cardiovascular mortality in end-stage renal disease. J Am Coll Cardiol 2009;53:1265-72. 99. Schneiderman J, Simon AJ, Schroeter MR, Flugelman MY, Konstantinides S, Schaefer K. Leptin receptor is elevated in carotid plaques from neurologically symptomatic patients and positively correlated with augmented macrophage density. J Vasc Surg 2008;48:1146-55. 100. Dahl TB, Yndestad A, Skjelland M, Øie E, Dahl A, Michelsen A, et al. Increased expression of visfatin in macrophages of human unstable carotid and coronary atherosclerosis: possible review role in inflammation and plaque destabilization. Circulation 2007;115:972-80. 101. Ramkumar N, Pappas LM, Beddhu S. Effect of body size and body composition on survival in peritoneal dialysis patients. Perit Dial Int 2005;25:461-9. 102.Huang CX, Tighiouart H, Beddhu S, Cheung AK, Dwyer JT, Eknoyan G, et al. Both low muscle mass and low fat are associated with higher all-cause mortality in hemodialysis patients. Kidney Int 2010;77:624-9. 103. Kalantar-Zadeh K, Streja E, Molnar MZ, Lukowsky LR, Krishnan M, Kovesdy CP, et al. Mortality prediction by surrogates of body composition: an examination of the obesity paradox in hemodialysis patients using composite ranking score analysis. Am J Epidemiol 2012;175:793-803. Sent to review: 8 Mar. 2014 | Accepted: 14 Apr. 2014 Nefrologia 2014;34(4):507-19 519 clinial case http://www.revistanefrologia.com © 2014 Revista Nefrología. Official Publication of the Spanish Nephrology Society Hypersensitivity reactions to synthetic haemodialysis membranes Rafael J. Sánchez-Villanueva1, Elena González1, Santiago Quirce2, Raquel Díaz1, Laura Álvarez1, David Menéndez1, Lucía Rodríguez-Gayo1, M. Auxiliadora Bajo1, Rafael Selgas1 1 Servicio de Nefrología. Hospital Universitario La Paz. Madrid (Spain); 2 Servicio de Alergología. Hospital Universitario La Paz. Madrid (Spain) Nefrologia 2014;34(4):520-25 doi:10.3265/Nefrologia.pre2014.May.12552 ABSTRACT Undergoing a haemodialysis (HD) session poses a certain risk of hypersensitivity adverse reactions as large quantities of blood are in contact with various synthetic materials. Hypersensitivity reactions to ethylene oxide and non-biocompatible membranes, such as cuprophane, have been described in HD. Cases of hypersensitivity with biocompatible membranes, such as polysulfone, and even polysulfone-polyvinylpyrrolidone, have also been reported. In this article we describe six cases of mostly early-stage hypersensitivity reactions to HD occurring in our department, characterised by malaise, desaturation, bronchospasm and arterial hypotension, with good response to the session’s temporary suspension and with reappearance in subsequent sessions that used a synthetic dialyser. No hypersensitivity reactions reappeared in successive observations when the sessions were carried out using a cellulose membrane. Keywords: Haemodialysis. Allergy. Polysulfone. Hypersensitivity reaction. Anaphylaxis. Eosinophilia. INTRODUCTION Undergoing a haemodialysis (HD) session poses a certain risk of hypersensitivity adverse reactions as large quantities of blood are in contact with various synthetic materials. These hypersensitivity reactions associated with the HD technique have been traditionally categorised into Correspondence: Rafael J. Sánchez Villanueva Servicio de Nefrología. Hospital Universitario La Paz. Paseo Castellana, 261. 28046 Madrid. (Spain). [email protected] [email protected] 520 Reacciones de hipersensibilidad a membranas sintéticas de hemodiálisis RESUMEN La realización de una sesión de hemodiálisis (HD) supone un cierto riesgo de aparición de reacciones adversas de hipersensibilidad, al estar en contacto abundantes cantidades de sangre con diferentes materiales de origen sintético. En HD han sido descritas reacciones de hipersensibilidad al óxido de etileno y a membranas no biocompatibles como el cuproamonio. También se han comunicado casos de hipersensibilidad con membranas biocompatibles como la polisulfona, e incluso con polisulfona asociada a polivinilpirrolidona. En este artículo queremos describir seis casos acontecidos en nuestro servicio de reacciones de hipersensibilidad mayoritariamente temprana a la sesión de HD, caracterizados por mal estado general, desaturación, broncoespasmo e hipotensión arterial, con buena respuesta a la suspensión temporal de la sesión y con reaparición en sesiones posteriores siempre que se utilizase un dializador sintético. Todas tienen en común no haberse dado de nuevo en sucesivas observaciones cuando las sesiones fueron realizadas con una membrana de celulosa. Palabras clave: Hemodiálisis. Alergia. Polisulfona. Reacción de hipersensibilidad. Anafilaxia. Eosinofilia. two types: type A or hypersensitivity reactions, which tend to occur immediately, and type B or non-specific reactions, which tend to start later1. Hypersensitivity reactions to ethylene oxide and nonbiocompatible membranes, such as cuprophane, have been described in HD2-4. Cases of hypersensitivity with biocompatible membranes, such as polysulfone, and even polysulfone-polyvinylpyrrolidone, a compound used to prevent possible adverse reactions produced by the interaction of the polysulfone membrane with platelets and plasma proteins, have also been reported5-7. Rafael J. Sánchez-Villanueva et al. Hypersensitivity reactions to membranes In this article we would like to describe 6 cases of adverse reactions to synthetic HD membranes in our department since 2011, with particular intensity between May and July 2013. CLINICAL CASES Case 1 A 58-year-old male patient, positive for hepatitis C virus (HCV), with chronic renal failure (CRF) secondary to adult hepatorenal polycystic disease, on the HD programme from 1996 to 2000, the year in which he received a cadavericdonor kidney transplant. Functioning transplant until May 2010, when he restarted HD due to stage 4-5T chronic allograft dysfunction secondary to chronic humoral rejection in the biopsy. The patient usually received highflux polysulfone dialyser by predilution online (Helixone ® FX-800, FMC). He had no known history of allergies. In July 2011, due to supply problems, the dialyser was changed to high-flux polyamide (Polyflux® 210H, Gambro). After being connected for 20 minutes, we noted oppressive chest pain accompanied by hypotension (blood pressure [BP] 80/40 mmHg) and 88% desaturation. Pulmonary auscultation did not reveal wheezing. After returning the circuit and prescribing high-flow oxygen, the patient improved spontaneously. After stabilising the vital signs (BP 130/70 and 94% baseline oxygen saturation), the session was restarted and ultrafiltration reduced, without further complications. In the following HD session, after being connected for 20 minutes, he presented the same symptoms as in the previous session (chest pain with hypotension and 78% oxygen saturation). The patient was returned to and prescribed high flow oxygen and 1g intravenous (IV) paracetamol. He improved noticeably following this treatment and consequently the HD session was restarted, finishing without complications. Given a suspicion of adverse reaction to the dialyser, we decided to change it in the following session to a polynephron membrane (Elisio TM-21H, Nipro). When he had been connected for 35 minutes, he experienced central chest pain, holocranial headache and abdominal pain. Pulmonary auscultation did not reveal wheezing. BP was 80/50mmHG, for which reason we returned to the patient. High doses of oxygen and 1g IV paracetamol were prescribed, with which the patient improved and 30 minutes after presenting symptoms, the HD session was restarted, which was completed without complications. Complementary tests (troponin I and electrocardiogram [ECG]) found no significant differences with respect to earlier tests. The analysis of the third session only showed leucopoenia (2,300 leukocytes/ml) with normal formula, the Nefrologia 2014;34(4):520-25 clinical case same magnitude of thrombocytopenia as previously (54,000 platelets/ml), slightly elevated C-reactive protein (CRP) (11.5mg/l) and increase of D-dimer (8,544ng/ml; 2,117ng/ ml in June 2011). Therefore, a computed tomography angiogram of the pulmonary arteries was requested, which showed pulmonary thromboembolism. Given a suspicion of possible allergy to synthetic membranes, we decided to perform the next HD session using cellulose triacetate (SureFlux®-21UX, Nipro). The patient did not present symptoms in either this session or in any subsequent session to date. Case 2 An 80-year-old female with CRF of multifactorial aetiology, on HD since May 2012. The patient had no known history of allergies. She regularly underwent HD using Helixone® FX-80 from the start. On 14 September 2012, an hour and a half into dialysis, she experienced sweating, tachypnoea and dyspnoea; 78% oxygen saturation was observed, overcome using highflow oxygen. Maintained BP. Pulmonary auscultation did not reveal wheezing. Analysis showed mild leukocytosis (12,500 leukocytes with normal formula), normal troponin I with CRP 8mg/l, with no other noteworthy findings. ECG was similar to previous tests. 20 minutes after presenting symptoms, spontaneous improvement of the patient was observed, finishing HD without complications. Post-HD thoracic radiography was performed, which did not show consolidations, effusion or vascular redistribution; it only showed the known increased cardiothoracic index. After this incident, HD sessions ran without problems for a month, until 17 October 2012, when the patient experienced sweating and significant dyspnoea during HD, with 76% oxygen saturation. Pulmonary auscultation did not reveal wheezing. The patient was administered oxygen at 5bpm, 200mg of IV hydrocortisone and 2 salbutamol inhalations 15 minutes apart. BP: 115/55mmHg. ECG was performed with sinus rhythm 98bpm, with no changes from the previous ECG. Analysis showed 19,000 leukocytes/ ml, 75% neutrophils (remainder of normal formula), CRP 18mg/l, negative troponin I, with no further alterations. On re-examining the patient, we examined the pruritus that had appeared on the lower limbs since the start of the session. Saturation improved to 98%, but the patient subsequently presented hypotension of 65/31mmHg, for which reason the circuit was returned and the session suspended. She was transferred to the Emergency department for observation, being discharged without symptoms the next day. Given the patient’s symptoms, we decided to change the filter to Poliflux ® 210H for the next HD session. 521 clinical case Rafael J. Sánchez-Villanueva et al. Hypersensitivity reactions to membranes Subsequent sessions ran without complications. On 24 October 2012 (third session with Poliflux), 1h from finishing HD, she experienced general discomfort, sweating, dyspnoea and hypotension (87/36mmHg). Pulmonary auscultation did not reveal wheezing. 200mg of hydrocortisone was administered, with complete disappearance of the symptoms. The filter was changed again to ElisioTM-21H for subsequent HD sessions, which ran without complications. On 7 June 2013, eight months later, the patient presented dyspnoea and non-irradiated, oppressive central chest pain 30 minutes into dialysis. BP: 210/75mmHg. 90% oxygen saturation with oxigen nasal cannula. Physical examination revealed general hypoventilation, with wheezing in all lung fields. Despite administering 300mg of hydrocortisone, the patient persisted with general wheezing; therefore we decided to stop HD and disconnect the whole system. An additional 200mg of hydrocortisone, 40mg of IV methylprednisolone and ipratropium bromide inhalation were administered. The patient’s clinical symptoms improved progressively, with respiratory symptoms disappearing. For this reason we decided to continue the HD session using SureFlux®21UX; the patient remained asymptomatic. Only CRP 21.6mg/l and haemoglobin 8.6g/dl stood out in the analysis, for which reason 2 red blood cell concentrates were transfused. ECG did not show changes from previous tests. SureFlux ®-21UX dialyser was kept for subsequent HD sessions, with no complications to date. Case 3 A 75-year-old male with stage 4 CRF, admitted to cardiology due to complete auricular-ventricular block requiring implantation of a pacemaker, along with symptoms of decompensated heart failure and secondary reduced renal function. The patient had no known history of allergies. On 28 May 2013, we opted for the patient’s acute HD treatment. Conventional HD using Helixone ® FX-100 Classix was prescribed. 15 minutes into the session, the patient suddenly experienced dyspnoea, 72% oxygen saturation and clinical signs of severe bronchospasm. The blood pump was stopped and 300mg of hydrocortisone and high-flow oxygen were administered. We decided to interrupt the HD session and, given the suspicion of adverse reaction to the dialyser, the blood was removed from the circuit. After 15 minutes the patient was asymptomatic. HD was not required until 16 June 2013, when a session was carried out using FX-100. After 15 minutes the patient experienced the same symptoms as previously and oxygen saturation reduced to 80%. The blood 522 pump was stopped and 300mg of hydrocortisone, 40mg of methylpredisolone and high-flow oxygen were administered. It was decided not to return the circuit’s blood, changing the dialyser to SureFlux ® -21UX. The patient slowly started to improve until symptoms completely disappeared, finishing the session with the new dialyser, and with no further complications to date. Case 4 A 48-year-old male, positive for human immunodeficiency virus and HCV, diagnosed with CRF of multifactorial origin, with no known history of allergies, who had stopped follow-up consultations and was admitted due to worsening renal function (Cr 15mg/dl), secondary to chronic diarrhoea of 6 months progression and sustained hypotension (70/40mmHg). During admission, the right jugular vein was channelled and one HD session was carried out on 16 July 2013. The Helixone ® FX-100 Classix dialyser was used. Two hours into treatment he experienced sudden dyspnoea, with 78%-80% oxygen saturation, presenting general hypoventilation with bibasal crackles and wheezing in both hemithorax in pulmonary auscultation. We decided to interrupt treatment and not return the system. Saturation rose to 98% following administration of high-flow oxygen and 100mg IV hydrocortisone, with pulmonary auscultation without pathological sounds and improvement of respiratory dynamic. The patient was transferred from the department, for which reason we lost the follow-up. Case 5 A 70-year-old male, solitary right kidney, with history of stage 5 CRF secondary to nephrosclerosis, with no known allergies, was admitted in June 2013 as scheduled for myocardial revascularisation due to chronic ischaemic heart disease expressed as lesion of the left coronary trunk and three vessels. During admission he presented multiple postoperative complications, requiring continuous techniques of kidney replacement therapy during his stay in the resuscitation unit using a polysulfone dialyser (Aquamax® HF-12, Baxter). After his transfer to the medical ward, periodic HD sessions with Helixone® FX 100 Classix were prescribed. 20 minutes into the first session, the patient experienced hypotension (80/40mmHg), dyspnoea and bronchospasm symptoms. After stopping the blood pump and returning the system, 200mg of hydrocortisone and high-flow oxygen were administered; the patient improved progressively. 20 minutes into the next HD session using the same filter, the clinical symptoms repeated. For this reason we decided to carry out subsequent HD sessions using cellulose triacetate (SureFlux ®-21UX), with no complications to date. Nefrologia 2014;34(4):520-25 Rafael J. Sánchez-Villanueva et al. Hypersensitivity reactions to membranes Case 6 An 83-year-old female patient, diagnosed with stage 5 CRF secondary to chronic pyelonephritis, admitted due to worsening renal function in the context of diarrhoea. The patient had no known history of allergies. Given the lack of improvement of the renal function, we decided to begin HD on 11 July 2013 using Helixone® FX-100 Classix. After 30 minutes of conventional HD, the patient presented symptoms of arterial hypotension, dyspnoea and 60-80% oxygen desaturation, accompanied by poor peripheral perfusion. High doses of oxygen and fluid therapy were administered, with improvement of BP, but not the clinical situation; therefore we decided to stop the HD session. After suspending dialysis, saturation returned to baseline values and the patient improved clinically. In subsequent sessions, the filter was replaced by SureFlux®-21UX, with no new complications to date. DISCUSSION We present a six-case series of mostly early-stage hypersensitivity reactions to an HD session, characterised by general malaise, desaturation, bronchospasm when determined, and arterial hypotension. There was good response to the session’s temporary suspension and reappearance of reactions in subsequent sessions which used a synthetic dialyser. No hypersensitivity reactions reappeared in successive observations of sessions using a cellulose membrane. No patients had a history of allergies and no causal relationship with the administered medication was found. As a peculiarity in the first two cases, there was the apparent saturation of the hypersensitivity mechanism for the dialyser that caused the reaction; that is, the reaction only occurred in the first moments and it was possible to resume HD using the previous dialyser, without complications. The remaining cases showed greater reaction severity and there was no other choice but suspension of HD. These cases were a learning curve for professionals in recognising the situation. The genesis of apparent universal hypersensitivity to synthetic membranes was also common among those patients in which a different membrane from the same group was tried. This procedure was not performed in some patients given the severity of their previous symptoms. After presenting symptoms, all patients were submitted to one or several HD sessions using a cellulose dialyser with no similar complications, centring the hypersensitivity process on the dialyser. The hospital’s allergologists admitted, after evaluating the cases, that they could be classified as serious hypersensitivity reactions to the polysulfone dialyser. Nefrologia 2014;34(4):520-25 clinical case We also attributed a certain epidemic character to the entire episode, due to the study being concentrated in two years, July 2011-July 2013, especially between May and July 2013. After this date, despite using the membrane in 90 % of our population, there was no reoccurrence of a similar case. The cases were notified to the Spanish Agency of Medicines as adverse reactions and they informed us that they had not received any similar correspondence. There are still yet to be further notifications on this matter. Traditionally hypersensitivity reactions to a dialyser have been considered as rare events (4 out of every 100,000 sessions); however, at the end of the 1980s, Nicholls et al. carried out a study in the United Kingdom and highlighted that the problem could be of greater significance 8. Type A hypersensitivity reactions regularly occurred in the first minutes of the HD session after blood came into contact with components of the extracorporeal circuit. These processes are mediated by preformed antibodies and, in the most serious cases, can cause dyspnoea, hypertension, unconsciousness, cardiac arrest and death. Given the suspicion of this adverse reaction, immediate action consists of stopping the blood pump, disconnecting the entire extracorporeal circuit, and administering highflow oxygen, as well as short-acting antihistamines and corticosteroids, hydrocortisone and starting assisted respiration where necessary. Type B hypersensitivity reactions, much less frequent, usually occur after the first 30 minutes of the HD session. Clinical signs are less specific, such as chest and back pain, and do not require the HD session to be interrupted. Bigazzi et al. described how, in the presence of contaminated fluid and through high-flux membranes, there could be back-filtration of pyrogens into the blood compartment. This causes hypersensitivity reactions at the start of the session in patients dialysed using these membrane types9. In the case of our patients, all were dialysed using highly permeable membranes and ultrapure water in accordance with European Pharmacopoeia standards 10. Complying with these regulations, with periodic monthly checks, and the absence of reactions in sessions immediately performed using another highly permeable, non-synthetic dialyser, make it very unlikely that it is the triggering mechanism of a hypersensitivity reaction. The majority of adverse reactions occurred between May and July 2013 in the patients’ first HD session using modified polysulfone dialysers. Cases of severe reactions to polysulfone have been described5,6, as well as hypersensitivity crossed to other types of membrane such as polycarbonate and polymethyl methylcrylate11. These reactions to polysulfone could be different depending on its manufacturer. Therefore, HD sessions using other synthetic dialysers were attempted in cases 1 and 2 without success. 523 clinical case Rafael J. Sánchez-Villanueva et al. Hypersensitivity reactions to membranes Another point of interest is the different sterilisation method of the dialysers. Müller et al. reported that vapoursterilisation could increase the dialyser’s biocompatibility in comparison to sterilisation using ethylene oxide 12. Golli-Bennour et al. affirmed that the membranes sterilised using vapour increased the viability of the endothelial cells compared to sterilisation methods using radiation or ethylene oxide13. In addition, they showed that, according to the sterilisation method, the concentration of serum malondialdehyde, used as a maker for lipid peroxidation, increased substantially with respect to healthy patients when the dialyser’s sterilisation was by gamma radiation or ethylene oxide. However, other authors have reported that vapour sterilisation does not seem to have an effect on the freeing of pro-inflammatory cytokines, such as interleukin-1. In our patients, membrane sterilisation was heterogeneous; FX and Poliflux dialysers are sterilised using vapour, while cellulose triacetate and Eliseo dialysers are sterilised using gamma rays, making it difficult to establish a causal relationship. A key finding in the cases in our department is that all hypersensitivity reactions disappeared after changing the dialyser to cellulose triacetate. Urbani et al. showed differences between the helixone and cellulose triacetate dialysers when they were studied through proteomics 14. Abundant proteins involved in the blood-dialyser interaction were found on the helixone membrane, such as ficolin-2 and fibrinogen fragments. Other authors had already demonstrated the absorption of ficolin-2 in polisulfone dialysers, which could contribute to the complement’s activation, leukocyte adhesion and, at worst, blood coagulation 15,16. In addition, it was published that cellulose triacetate induces less hypersensitivity reactions, probably due to less activation of the platelet membrane (GpIIb/IIIa), producing less aggregation disease 17. The mechanisms making our patients sensitive to the described synthetic dialysers and not to the cellulose triacetate dialyser are not clear. Therefore we are designing specific ex vivo response studies on immunocompetent cells for those patients who showed allergic reaction to synthetic dialysers, as well as cross-sectional response studies on hypersensitivity with various HD membranes. Adverse reactions to dialysers are a severe complication intrinsic to the therapy itself. The nephrologists should be alert to this possibility, acting immediately faced with mere clinical suspicion and referring the patient to the allergy department to complete the study as soon as possible. Acknowledgements The authors thank Dr. Rafael Pérez García for his revision and correction of this article. 524 Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. REFERENCES 1. Daugirdas JT, Ing TS. First-use reactions during hemodialysis: a definition of subtypes. Kidney Int Suppl 1988;24:S37-43. 2. Caruana RJ, Hamilton RW, Pearson FC. Dialyzer hypersensitivity syndrome: possible role of allergy to ethylene oxide. Report of 4 cases and review of the literature. Am J Nephrol 1985;5:271-4. 3. Lemke HD, Heidland A, Schaefer RM. Hypersensitivity reactions during haemodialysis: role of complement fragments and ethylene oxide antibodies. Nephrol Dial Transplant 1990;5:264-9. 4. Bommer J, Ritz E. Ethylene oxide (ETO) as a major cause of anaphylactoid reactions in dialysis (a review). Artif Organs 1987;11:111-7. 5. Arenas MD, Gil MT, Carreton MA, Moledous A, Albiach B. [Adverse reactions to polysulphone membrane dialyzers durind hemodialysis]. Nefrologia 2007;27:638-42. 6. Ohashi N, Yonemura K, Goto T, Suzuki H, Fujigaki Y, Yamamoto T, et al. A case of anaphylactoid shock induced by the BS polysulfone hemodialyzer but not by the F8-HPS polysulfone hemodialyzer. Clin Nephrol 2003;60:214-7. 7. Bacelar Marques ID, Pinheiro KF, de Freitas do Carmo LP, Costa MC, Abensur H. Anaphylactic reaction induced by a polysulfone/ polyvinylpyrrolidone membrane in the 10th session of hemodialysis with the same dialyzer. Hemodial Int 2011;15:399403. 8. Nicholls AJ. Hypersensitivity to hemodialysis: the United Kingdom experience. Artif Organs 1987;11:87-9. 9. Bigazzi R, Atti M, Baldari G. High-permeable membranes and hypersensitivity-like reactions: role of dialysis fluid contamination. Blood Purif 1990;8:190-8. 10. European Pharmacopeia. Haemodialysis solutions, concentrated, water for diluting. 3rd ed. 1997. 11. Tanoue N, Nagano K, Matsumura H. Use of a light-polymerized composite removable partial denture base for a patient hypersensitive to poly(methyl methacrylate), polysulfone, and polycarbonate: a clinical report. J Prosthet Dent 2005;93:17-20. 12.Muller TF, Seitz M, Eckle I, Lange H, Kolb G. Biocompatibility differences with respect to the dialyzer sterilization method. Nephron 1998;78:139-42. 13.Golli-Bennour EE, Kouidhi B, Dey M, Younes R, Bouaziz C, Zaied C, et al. Cytotoxic effects exerted by polyarylsulfone dialyser membranes depend on different sterilization processes. Int Urol Nephrol 2011;43:483-90. 14.Urbani A, Sirolli V, Lupisella S, Levi-Mortera S, Pavone B, Pieroni L, et al. Proteomic investigations on the effect of different membrane materials on blood protein adsorption during haemodialysis. Blood Transfus 2012;10 Suppl 2:s101-12. 15. Mares J, Thongboonkerd V, Tuma Z, Moravec J, Matejovic M. Specific adsorption of some complement activation proteins to polysulfone dialysis membranes during hemodialysis. Kidney Int Nefrologia 2014;34(4):520-25 Rafael J. Sánchez-Villanueva et al. Hypersensitivity reactions to membranes 2009;76:404-13. 16. Mares J, Richtrova P, Hricinova A, Tuma Z, Moravec J, Lysak D, et al. Proteomic profiling of blood-dialyzer interactome reveals involvement of lectin complement pathway in hemodialysisinduced inflammatory response. Proteomics Clin Appl clinical case 2010;4:829-38. 17. Kuragano T, Kuno T, Takahashi Y, Yamamoto C, Nagura Y, Takahashi S, et al. Comparison of the effects of cellulose triacetate and polysulfone membrane on GPIIb/IIIa and platelet activation. Blood Purif 2003;21:176-82. Sent to review: 3 Apr. 2014 | Accepted 15 May. 2014 Nefrologia 2014;34(4):520-25 525 letters to the editor A) COMMENTS ON PUBLISHED ARTICLES Comment on “Kaposi´s sarcoma in the early post-transplant period in a kidney transplant recipient” Nefrologia 2014;34(4):526 doi:10.3265/Nefrologia.pre2014.Apr.12473 To the Editor,, We have read the article by Ercam et al. in the Clinical Case Section of Nefrologia about a case of Kaposi’s sarcoma in a transplant recipient.1 Renal transplantation and immunosuppressive medication used for it leads to a high rate of tumors and among them Kaposi’s sarcoma is common. There is extensive literature on the development of malignancies after renal transplantation, so the description of another case does not seem to justify its publication. However, what seems novel and so the authors justify its interest is the prematurity of the Kaposi´s sarcoma development (only 4 months after renal transplantation), together with the authors statement that this would be the first reported case with this precocity.1 In 1990 we published a case of Kaposi’s sarcoma associated with renal transplant developed 4 years after kidney transplant2 and in which the skin lesions stabilized after withdrawing immunosuppressive medication. In the discussion of the case we pointed out references describing cases in 1979 and the time of appearance of the tumor could be even after three months of transplantation.3 Interestingly before the time of our communication there have been published some references describing cases where tumor appear between first and 4 months after renal transplantation.4,5 It is true that most of the cases described in the literature the time elapsed from transplant to tumor development are longer than that of Ercam et al. and 526 the well documented case by this authors is unusual on this matter, however it is also true that we get used to refer recent references in our publications, without taking into account some previous periods. To be fair we should not forget that it is not easy to find past issues, either completely or it abstract. Finally note that these circumstances should encourage us to avoid statements like “the first or only case or reference” given the lack of access to all available information. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1. Ercan Z, Demir ME, Merhametsiz O, Yayar O, Ulas T, Ayli MD. Kaposi´s sarcoma in the early post-transplant period in a kidney transplant recipient. Nefrologia 2013;33(6):861-2. 2. Ambrojo P, Coronel F, Macia M, Gutierrez Marcos F, Sanchez Yus E. Sarcoma de Kaposi asociado a trasplante renal. Actas Dermo-Sif 1990;81(9):576-8. 3. Harwood AR, Osoba D, Hofstader SL, Goldstein MB, Cardella CJ, Holecek MJ, et al. Kaposi´s sarcoma in recipients of renal transplants. Am J Med 1979;67:759-65. 4. Qunibi W, Akhtar M, Sheth K, Ginn HE, Al-Furayh O, DeVol EB, et al. Kaposi´s sarcoma: the most common tumor after renal transplantation in Saudi Arabia. Am J Med 1988;84(2):225-32. 5. Little PJ, Farthing CF, Al Khader A, Bunuan H, Haleem A. Kaposi’s sarcoma in a patient after renal transplantation. Postgrad Med J 1983;59:325-6. Francisco Coronel1, Manuel Macía2 Servicio de Nefrología. Ex Jefe de sección. Hospital Clínico San Carlos. Madrid (Spain); 2 Servicio de Nefrología. Hospital Universitario Ntra. Sra. de Candelaria. Santa Cruz de Tenerife (Spain). Correspondence: Francisco Coronel Comunidad de Baleares, 1. Las Rozas. 28231, Madrid. (Spain). [email protected] 1 Increase of ischaemic colitis incidence in haemodialysis Nefrologia 2014;34(4):526-7 doi:10.3265/Nefrologia.pre2014.Apr.12328 To the Editor, Ischaemic colitis (IC) is a disease with an increasing incidence in haemodialysis (HD) patients, due to their changing profile (significantly older, with more cardiovascular disease and with increased survival in relation to the past)1. Despite the fact that IC can be secondary to vascular thrombosis or mesenteric vasospasm, the most frequent aetiology in HD patients is low output, which occurs during the session usually as a consequence of a lowering of blood pressure. The case published by Gutiérrez-Sánchez et al.2, despite concerning a patient who had only been on HD for two months, presented many of the classic characteristics of patients with non-occlusive ischaemic colitis: high vascular risk patient with hypotensive episode who developed rectorrhagia and abdominal pain2. In the study recently published by our group involving the most cases of non-occlusive IC in HD, the factors associated with suffering this disease were older age, diabetes mellitus (DM), cardiovascular history (such as peripheral vascular disease), time on dialysis and resistance to erythropoietin. This last parameter is shown to be an independent predictor in multivariate analysis (together with DM and time on HD), demonstrating the association of this symptom with inflammation and, consequently, with atherosclerosis3. In a published study that included incident patients on dialysis (HD and peritoneal dialysis), the risk factors associated with suffering from non-occlusive IC were similar, apart from time on dialysis. However, on studying the various Nefrologia 2014;34(4):526-44 letters to the editor techniques, the authors found that the patients on peritoneal dialysis had a 1.5 times increased risk of suffering from this condition, despite being younger and having less comorbidity, which they associated with exposure to solutions with a high dextrose content4. In this case series, the authors found 80 % mortality; this contrasts to our study in which mortality in the acute episode was 59 %. However, we performed a case-control study with patients who survived the acute episode over an average of 56 months (± 69). We found that the patients with non-occlusive IC had significantly lower survival, attributable to the condition being the result of these patients’ high cardiovascular risk. In fact, the causes of death were divided into infectious and cardiovascular. To date, the only study that compared survivors of non-occlusive IC with patients on HD was that by Bassilios et al., which showed identical survival in both groups, probably because it only included in the analysis those patients who survived more than three months5. As regards treatment, as was the case in the abovementioned study, it is usual Nefrologia 2014;34(4):526-44 to administer wide-spectrum antibiotic therapy and have a wait-and-see approach; surgery is opted for in the minority of cases (only 33 % in our study), which is likely due to the patients’ profile (elderly, with cardiovascular risk, etc.). In fact, our results only revealed significant differences in age (younger) when we compared candidates for surgery with those in which a conservative approach was maintained. Previous studies have shown that the delay in carrying out surgery following diagnosis is associated with an increase in mortality6. As a result, it seems reasonable to establish a more conservative ultrafiltration profile in patients at high risk of suffering from non-occlusive IC, due to its harmful consequences in HD patients Martín-Navarro JA, López-Quiñones Llamas M. Ischaemic colitis in haemodialysis. Nefrologia 2013;33(5):736-7. 3. Quiroga B, Verde E, Abad S, Vega A, Goicoechea M, Reque J, et al. Detection of patients at high risk for non-occlusive mesenteric ischemia in hemodialysis. J Surg Res 2013;180(1):51-5. 4. Li SY, Chen YT, Chen TJ, Tsai LW, Yang WC, Chen TW. Mesenteric ischemia in patients with end-stage renal disease: a nationwide longitudinal study. Am J Nephrol 2012;35(6):491-7. 5. Bassilios N, Menoyo V, Berger A, Mamzer MF, Daniel F, Cluzel P, et al. Mesenteric ischemia in hemodialysis patients: a casecontrol study. Nephrol Dial Transplant 2003;18:911-7. 6. Bender JS, Ratner LE, Magnuson TH, Zenilman ME. Acute abdomen in the hemodialysis patient population. Surgery 1995;117:494-7. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1. Valentine RJ, Whelan TV, Meyers HF. Nonocclusive mesenteric ischemia in renal patients: recognition and prevention of intestinal gangrene. Am J Kidney Dis 1990;15:598-600. 2. Gutiérrez-Sánchez MJ, Petkov-Stoyanov V, Borja Quiroga Servicio de Nefrología. Hospital General Universitario Gregorio Marañón. Madrid. (Spain). Correspondence: Borja Quiroga Servicio de Nefrología. Hospital General Universitario Gregorio Marañón. Doctor Esquerdo, 46. 28007, Madrid. (Spain). [email protected] 527 letters to the editor B) BRIEF PAPERS ON RESEARCH AND CLINICAL EXPERIMENTS Home haemodialysis: a right and a duty Nefrologia 2014;34(4):528-9 doi:10.3265/Nefrologia.pre2014.Feb.12476 To the Editor, There is a growing interest in home haemodialysis (HHD) both in Spain’s neighbouring countries and in the United States. This interest has arisen out of the limitations of the conventional three-weekly therapy sessions, shown in studies such as HEME1, in order to increase the survival of stage 5 chronic kidney disease patients. There is an increasing number of publications that back home therapies in terms of quality of life2, blood pressure management, reduction of left ventricular hypertrophy, calcium-phosphorus control, anaemia, nutritional state and lower morbidity and mortality4,5, when compared to classic treatment plans; there are also studies supporting this treatment for its reduction of costs6. For this reason, we think it opportune to present our experience in implementing a short daily HHD programme. Between March 2008 and November 2013, we included 10 patients (3 in 2008, 0 in 2009, 1 in 2010, 1 in 2011, 4 in 2012 and 1 in 2013); 50% were females, with an average age of 61 (range: 38-81), distance to the centre 42 km (range: 0-122 km) and remained in the technique for 32 ± 17 months. As regards the origin of the patients: five came from outpatient consultations, three were on peritoneal dialysis and two from a peripheral centre. In terms of the programme exits, there were two deaths and two transplants. No patient required a change of renal replacement therapy and there were no losses in the training period. In terms of morbidity, we had two hospitalisations in 2008, one in 2009, two in 2010, none in 2011, one in 2012 and six in 2013 (we should point out that half of the hospitalisations were scheduled). The reasons for admission were: three cardiovas- cular, two infectious (associated with vascular access, in 2008 and 2010), one neoplasia, one digestive, two due to vascular access of non-infectious cause (insertion of tunnelled catheter and closure of fistula aneurysm) and three due to other causes (scheduled nephrectomy, herniorrhaphy and clinical deterioration). The prescribed haemodialysis plan and the results obtained are presented in Table 1 and Figure 1. Regarding drugs, we used: - Antihypertensives: 43% did not require any antihypertensive drug, 53% required one drug, and only 4%, two or more. - Phosphate binders: the use of a binder was not required in 47% of the monthly checks; only one type of binder was needed in 35% of cases, predominantly calcium over non-calcium based binders; while a combination of various types of binders was required in the remaining cases. Although the average calcium carbonate dose Table 1. Description of the results Incidence Prevalence No.hospitalisationsª 2008 3 3 2 2009 0 3 1 (1) 2010 1 3 2 (1) 2011 1 4 0 2012 4 7 1 2013 1 6 6 (4) Total 10 Qs ml/min 323.33 338.88 348.61 327.08 317.26 306.89 12 (6) Mean 322.68±25.98 Qd ml/min Time min/session No. sessions/week Std Kt/V Hb g/dl EPO UI/kg/week Phosphorus mg/dl PTH pg/ml MAP mmHg %Weight gain Albumin g/dl 685 130.7 5.63 3.2 12.1 118.34 4.38 271.95 89.43 1.8 4.4 705.55 129.4 5.66 3.05 12.02 88.5 4.56 278.66 93.19 2.5 4.19 737.5 132.9 5.75 3.07 11.62 42.54 4.98 297.29 95.07 2.3 4.24 631.25 130 5.97 3.33 11.23 38.54 4.97 292.18 86.62 1.9 4.03 586.3 130.6 5.76 3.27 10.64 62.58 4.82 390.56 86.93 1.3 4.17 533.03 143.9 5.08 2.98 11.3 80.31 4.58 360.51 91.18 1.5 4.17 619.85±128.03 134.76±18.7 5.56±0.6 3.15±0.4 11.3±1.1 69.34±71.8 4.73±1.2 324.89±171.4 90.27±14.7 1.8±1.4 4.16±0.3 PTH: parathyroid hormone. ª Scheduled hospitalisations in brackets. 528 Nefrologia 2014;34(4):526-44 letters to the editor used initially was high, 3829.8mg/ day, there was subsequently a progressive substitution for calcium acetate, averaging 815.16mg/day. The other binders used were: aluminium hydroxide 77.66mg/day (one-off use and not used at present), 2478.83mg/day of sevelamer and 909.66mg/day of lanthanum carbonate. - Calcimimetic or vitamin D analogues: their use was not required for controlling parathyroid hormone values in 15% of cases; only paricalcitol was used in 40% of cases, cinacalcet in 21%, and a combination in the remaining cases (24%). The average cinacalcet dose used was 28.9mg/day, and 3.84µg/week of paricalcitol. - EPO: average dose was 69.34±71, 85UI/kg/week. It must be highlighted that we did not observe any microbiological or chemical contamination in the checks carried out. In terms of technical complications, it must be noted that when dialysis treatment could not be carried out on the planned day, the patient took an un-planned break or went to hospital, on three occasions; we believe this fact to be anecdotic considering that more than 6000 sessions were undertaken in the study’s period. The results obtained in clinical-analytical and morbidity and mortality terms surpass, or are at least comparable to, the standard quality of care objectives, with no incidences observed in relation to the patients’ safety. In addition, the technique has enabled a considerable improvement in patients’ quality of life. For these reasons, we consider that the patient has a right to the option of HHD, and therefore it is our duty to offer it. We believe that to do so, we must broaden patient selection criteria, not being led by preconceived ideas and strengthening the physical substrate in order to implement these programmes. 100 90 80 70 60 50 Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1. Eknoyan G, Beck GJ, Cheung AK, Daurgidas JT, Greene T, Kusek JW, et al. Effect of dialysis dose and membrane flux in maintenance hemodialysis. N Engl J Med 2002;347(25):20109. 2. Finkelstein FO, Schiller B, Daoui R, Gehr TW, Kraus MA, Lea J, et al. At-home short daily hemodialysis improves the long-term health-related quality of life. Kidney Int 2012;82(5):561-9. 3. Daugirdas JT, Chertow GM, Larive B, Pierratos A, Greene T, Ayus JC, et al. Effects of frequent hemodialysis on measures of CKD mineral and bone disorder. J Am Soc Nephrol 2012;23(4):727-38. 4. Kjellstrand C, Buoncristiani U, Ting G, Traeger J, Piccoli GB, Sibai-Galland R, et al. Survival with short-daily hemodialysis: Association of time, site, and dose of dialysis. Hemodial Int 2010;14(4):464-70. 5. Johansen KL, Zhang R, Huang Y, Chen SC, Blagg CR, Goldfarb-Rumyantzev AS, et al. Survival and hospitalization among patients using nocturnal and short daily compared to conventional hemodialysis: a USRDS study. Kidney Int 2009;76(9):984-90. 6. Komenda P, Gavaghan M, Garfield S, Poret A, Sood M. An economic assessment model for in-center, conventional home, and more frequent home hemodialysis. Kidney Int 2012;81:307-13. 7. MATCH.D group. Method to assess treatment choices for home dialysis (MATCH-D). Available at: http://homedialysis.org/match-d. 40 Alejandro Pérez-Alba, J. Ramón Pons-Prades, Esther Tamarit-Antequera, Juan J. Sánchez-Canel, Vicente Cerrillo-García, Elena Renau-Ortells, Laura Salvetti, M. Ángeles Fenollosa-Segarra 30 20 10 0 Std Kt/V AVF Hb Iron Ca Extended range - AVF+CAT - P 5.1-5.5 - PTH 301-500 P CaxP PTH Target range Figure 1. Percentage of the quality indicators obtained. Alb: albumin; PTH: parathyroid hormone. Nefrologia 2014;34(4):526-44 MAP %G Alb Servicio de Nefrología. Hospital General de Castellón. (Spain). Correspondence: Alejandro Pérez Alba Servicio de Nefrología. Hospital General de Castellón. Avenida Benicasim, s/n. Castellón de La Plana,12004. (Spain).. [email protected] [email protected] 529 letters to the editor IInfluence of glucose solutions on the development of hyperglycaemia in peritoneal dialysis. Behaviour of glycated haemoglobin and the lipid profile Nefrologia 2014;34(4):530-1 doi:10.3265/Nefrologia.pre2014.Mar.12394 Sr. Director: Peritoneal dialysis (PD) is a technique that exposes the patient to glucose solutions and may cause metabolic complications, such as central obesity, hypertriglyceridaemia and hyperglycaemia. Glucose absorbed from the peritoneal cavity may lead to the development of insulin resistance (IR) and de novo diabetes1. Furthermore, exposure to glucose degradation products (GDP) leads to structural and functional damage of the peritoneal membrane2. In a study by Fortes et al., PD patients had higher fasting glucose, glycated haemoglobin (HbA1C) and estimated IR rate using the HOMA-IR index3 than haemodialysis patients. In addition, patients who receive dialysis with glucose-free dialysate show a lower absorption of glucose, lower weight gain and fat accumulation, and improved IR and dyslipidaemia4; furthermore, the use of icodextrin leads to increased adipocytokines in the plasma of PD patients, without changes in cholesterol levels, but with a reduction in triglycerides5. In a study aimed at observing differences in the lipid profile of 22 non-diabetic patients on PD between 6 and 48 months compared to a control group of a similar age, there were significantly higher levels of very low-density lipoproteins, cholesterol bound to low-density lipoproteins and triglycerides, and significantly lower levels of cholesterol bound to high-density lipoproteins compared to the control group6; using a 72-hour continuous glucose-monitoring system, they studied the effect of PD 530 glucose solutions on patient glucose levels and they observed that the percentage of glucose levels above 90mg/dl was influenced by high glucose concentrations in the fluids and the high transporter state. However, a Spanish study recently published that non-diabetic PD patients did not have a significant increase in HOMA-IR levels, or modifications to these values after one year of treatment on PD, or statistically significant changes in the lipid profile7. We carried out a retrospective observational study with 39 non-diabetic PD patients of the Hospital Clínico San Carlos de Madrid, 26 on continuous ambulatory PD and 13 on automated PD, of 61+14 years of age, in which we analysed baseline glucose and lipids (total cholesterol and triglycerides) before beginning PD and after 1, 3, 6, 12, 18, 24, 30 and 36 months using the technique, and a prospective 12-month study in 18 of the patients, also analysing HbA1C. We studied time on PD, the type of PD, the type of transporter and use of solutions with a high glucose load (two or more exchanges at 2.3%) or a low load (fewer than two at 2.3% and/ or icodextrin). We only used fluids with a high glucose load in 6 patients and we did not use 3.86%-4.25% solutions in any patient. The type of transporter was high (medium-high, high) in 16 and low (medium-low, low) in 23. We did not find significant differences between the pre-PD glucose means and those found over the 36 months of follow-up (Table 1), which remained at normal levels throughout the study. Cholesterol levels rose suddenly in the sixth month with respect to baseline values (171±45 vs. 193.5±46mg/ dl; P=.008), without changes in the triglyceride figures and with normal levels being maintained in both factors throughout follow-up. In the prospective study with 18 patients, we did not observe significant differences in glycaemia evolution: baseline 103±14 vs. 105±17 after 1 month, 112±14 after 3 months, 108±20 after 6 months and 104±14mg/dl after 12 months. No significant differences were observed in HbA1C: baseline 5.5±0.5 vs. 5.5±0.5 after 1 month, 5.4±0.6 after 3 months, 5.7±0.8 after 6 months and 5.4±0.6% Table 1. Evolution of glycaemia in peritoneal dialysis. Par 1 Par 2 Par 3 Par 4 Par 5 Par 6 Par 7 Par 8 Glycaemia No. Mean±SD Baseline 39 93.8±13.8 1 month 39 99.5±16 Baseline 39 98.8±13.8 3 months 39 104.9±18 Baseline 37 98.6±14 6 months 37 101±16.4 Baseline 31 97.9±14 12 months 31 98±11.2 Baseline 27 98±14.9 18 months 27 98.9±12.2 Baseline 23 97.8±14.9 24 months 23 100.2±1.2 Baseline 17 96.3±12.7 30 months 17 97.7±8.14 Baseline 13 94.4±8.9 36 months 13 97±14.1 P 0.77 0.05 0.38 0.55 0.81 0.52 0.72 0.58 SD: standar desviation. Nefrologia 2014;34(4):526-44 letters to the editor after 12 months. Glycaemia and HbA1C do not seem to change in accordance with the glucose load. There is a good correlation between glucose and HbA1C. High transporters have higher glucose values after one month on PD (P=.039), but not of HbA1C. During the first years in which PD has been reported, and on the basis of the glucose load that was contributed to obtain sufficient ultrafiltration, it was considered to be a dialysis technique with a potential diabetogenic effect. It is possible that in these first few years, due to a lack of knowledge about the deleterious effect that glucose contribution has on the peritoneum with the development of GDP 2, the relatively common use of very hypertonic solutions, which furthermore did not use bicarbonate as a buffer, may have caused some cases of diabetes.In the last decade since the introduction of solutions in dual chambers with a mixture of lactate and bicarbonate or bicarbonate alone, with which the formation of GDP is minimal and use of 3.86%-4.25% glucose PD dialysate is practically nil, the induction of diabetes and even the development of moderate hyperglycaemia, as our study shows, have become anecdotal. The increase in lipids reported in some articles 6 is not relevant in our study in terms of its maintenance over time and it has not been confirmed by other authors 7. In conclusion, our non-diabetic PD patients treated with glucose solutions did not show changes in their glucose levels throughout the 36 months on dialysis. HbA1C was unchanged after a year on the technique. The potential development of diabetes in PD was not confirmed by our results. 1. Szeto CC, Chow KM, Kwan BCH, Chung KY, Leung CB, Li PKT. New-onset hyperglycemia in nondiabetic Chinese patients started on peritoneal dialysis. Am J Kidney Dis 2007;49:524-32. 2. Kim YL, Cho JH, Choi JY, Kim CD, Park SH. Systemic and local impact of glucose and glucose degradation products in peritoneal dialysis solution. J Ren Nutr 2013;23(3):218-22. 3. Fortes PC, de Moraes TP, Mendes JG, Stinghen AE, Ribeiro SC, Pecoits-Filho R. Insulin resistance and glucose homeostasis in peritoneal dialysis. Perit Dial Int 2009;29:S145-8. 4. Cho KH, Do JY, Park JW, Yoon KW. Effect of icodextrin dialysis solution on body weight and fat accumulation over time in CAPD patients. Nephrol Dial Transplant 2010;25:593-9. 5. Furuya R, Odamaki M, Kumagai H, Hishida A. Beneficial effects of icodextrin on plasma level of adipocytokines in peritoneal dialysis patients. Nephrol Dial Transplant 2006;21:494-8. 6. Johansson AC, Samuelsson O, Attman PO, Haraldsson B, Moberly J, Knight-Gibson C, et al. Dyslipidemia in peritoneal dialysis-relation to dialytic variables. Perit Dial Int 2000;20:306-14. 7. Sánchez-Villanueva R, Estrada P, del Peso G, Grande C, Díez JJ, Iglesias P, et al. Análisis repetido de la resistencia insulínica estimada mediante índice HOMAIR en pacientes no diabéticos en diálisis peritoneal y su relación con la enfermedad cardiovascular y mortalidad. Nefrologia 2013;33(1):85-92. Margarita Delgado-Córdova1, Francisco Coronel2, Fernando Hadah2, Secundino Cigarrán3, J. Antonio Herrero-Calvo2 1 Universidad Autónoma de Chile. Santiago de Chile (Shile); 2 Servicio de Nefrología. Hospital Clínico de San Carlos. Madrid. (Spain).; 3 Sección de Nefrología. Hospital da Costa. Burela, Lugo (Spain). Conflicts of interest The authors declare that they have no conflicts of interest related to the contents of this article. Nefrologia 2014;34(4):526-44 Correspondence: Francisco Coronel C/ Comunidad de Baleares 1, Las Rozas, 28231 Madrid, (Spain). [email protected] Results 5 years after living donor renal transplantation without calcineurin inhibitors Nefrologia 2014;34(4):531-4 doi:10.3265/Nefrologia.pre2014.May.11810 To the Editor, Calcineurin inhibitor-based (CNI) immunosuppression regimens have improved the outcomes of renal transplantation. Unfortunately, the use of CNI has been associated with interstitial fibrosis and tubular atrophy, affecting graft function and graft survival1. In order to avoid exposure to CNI, agents such as sirolimus (SRL) have emerged as new therapeutic options. Therapeutic strategies with SRL include the minimisation, suspension, elimination and total absence of CNI2. Experiences with CNI-free SRL/mycophenolate mofetil (MMF)/ST immunosuppression have not obtained sufficient acute rejection (AR) prophylaxis 3. The introduction of induction therapy improved AR rates and short-term efficacy (1-3 years) with contradictory results 4-7. We previously reported excellent and satisfactory results after 1 and 3 years without CNI 8,9 and we now present an observational and retrospective study of efficacy and safety after 5 years of the SRL/MMF/ST regimen compared with cyclosporine (CS)/ MMT/ST and selective induction with basiliximab in 41 patients enrolled between May 2004 and January 2005. The study design has previously been reported in detail8. In this report, the results were analysed in two populations: the intention-to-treat (ITT) population, which included all patients with a functioning graft, and the population on treatment (OT), which included patients who were maintained on the same original study immunosuppression regimen. 531 letters to the editor The demographic data of patients are displayed in Table 1. Five-year patient survival was 90% in the SRL group and 80.9% in the CS group (p=ns). The causes of death in the SRL group were cardiovascular (n=1) and infectious (n=1), which was similar to the CS group: cardiovascular (n=2), infectious (n=2) and gastrointestinal bleeding (n=1). Five-year graft survival was 80% for SRL and 76.1% for CS (p=ns). The causes of graft loss in the SRL group were: graft thrombosis (n=1), de novo glomerulonephritis (n=1), urological complications (n=1) and a lack of adherence to treatment (n=1). In the CS group they were: graft thrombosis (n=1), de novo glomerulonephritis (n=1), lupus (n=1), chronic kidney disease (n=1) and death with a functioning graft (n=1). Eight patients (40%) from the SRL group and 3 (14%) from the CS group received basiliximab induction. After 5 years, there was a decrease in the dose of CS (133±29.9mg/day, range 120-200) and of SRL (1.75±0.66mg/ day, range 1-3) compared to 12 months after transplantation (205.7±66mg/day and 3.2±1.7mg/day CS and SRL, respectively). The mean dose of MMF was higher in the CS group (1218.75±363g/day, range 5002000), compared with the SRL group (1093.9±417g/day, range 500-2000) (p=.3). All patients in the study continued to take 5mg/day of oral prednisone. Four patients (25%) in the CS group (p=.039) with a functioning graft changed their regimen to SRL due to interstitial fibrosis and tubular atrophy confirmed by biopsy. We maintained all patients in the SRL group with a functioning graft on the SRL/MMF/ST regimen. After one year of follow-up, 2 patients in the SRL group (11.1%) and 3 in the CS group (17.7%) had episodes of AR (p=ns). Graft function calculated by the glomerular filtration rate estimated using the MDRD (Modification of Diet in Renal Disease) formula10 and serum creatinine is displayed in Table 2. We did not find a statistically significant difference between the two groups, independently of whether they were an ITT population or a population OT. Patients in the SRL group had a higher elimination of proteins in 24h urine (p=.039) than patients in the CS group in the ITT population. Serum haemoglobin was similar in both cases. Cholesterol and triglycerides were significantly higher in the SRL group (Table 2). There were a total of 81 adverse effect events, which were mostly infectious (14 in the SRL group and 16 in the CS group). There was a similar incidence in new onset diabetes after transplantation (NODAT) (10% in the SRL group versus 9.5% in the CS group). No patient developed a malignancy during follow-up. Six patients (37.5%) in the SRL group and 31.3% (n=5) in the CS group were taking angiotensin-converting-enzyme inhibitors and/or angiotensin receptor blockers after 5 years (p=.7). Similarly, more patients in the SRL group were taking lipid-lowering drugs than in the CS group (n=7, 43.8%, versus n=6, 37.5%) (p=.2). In summary, despite the fact that our results need to be carefully reviewed due to certain limitations, such as the sample size, retrospective recording and a population of low immunological risk, we concluded that living donor transplantation patients with selective induction on the SRL/MMF/ST regimen have similar graft survival and function 5 years after transplantation to those on the CSA/ MMF/ST regimen. Table 1. Clinical and demographic parameters Group A SirolimusCyclosporine P value Patients (n) Recipient’s age (years), mean SD (range) Sex (male:female) BSA, mean SD (range) Dialysis time (months), mean (range) HLA match, mean SD (range) Donor’s age (years), mean (range) Group B 20 21 ns 29,6 7,6 (18-40) 31,2 9,21 (18-52) ns 12:8 12:9 ns 1,73 0,24 (1,31-2,19) 1,63 0,1 (1,43-1,97) ns 24,25 13,7 (2-62) 26 12,6 (3-60) ns 2,7 1 (0-5) 2,9 1,1 (0-4) ns 37,8 (21-56) 37,9 (27-59) ns CMV serology D+/R- 22 D+/R+ 1416 D-/R- 22 D-/R+ 21 CMV: cytomegalovirus, ns: not significant, SD: standard deviation. 532 Nefrologia 2014;34(4):526-44 letters to the editor Table 2. Graft function based on the analysis of patients on treatment and those who we intended to treat MDRD eGFR (ml/min/1,73 m2) ITT population Mean±SD (range) Population OT Mean±SD (range) Serum creatinine (mg/dl) ITT population Mean±SD (range) Population OT Mean±SD (range) Protein in 24h urine (mg/day) ITT population Mean±SD (range) Population OT Mean±SD (range) Haemoglobin (g/dl) ITT population Mean±SD Population OT Mean±SD Total cholesterol (mg/dl) ITT population Mean±SD Population OT Mean±SD Triglycerides in blood (mg/dl) ITT population Mean±SD Population OT Mean±SD Group A (SRL) Group B (CSA) n = 16 53.8±19 (20-90.9) n = 16 53.8±19 (20-90.9) n = 16 54.7±18.7 (29-83.7) n = 12 54.1±19.1 (29-83.7) n = 16 1.6±0.6 (1.0-3.7) n = 16 1.6±0.6 (1.0-3.7) n = 16 1.49±0.4 (1.0-2.2) n = 12 1.47±0.5 (1.0-2.2) n = 16 293.6±280 (50-814) n = 16 293.6±280 (50-814) n = 16 110.6±192 (0-620) n = 12 136.7±205 (0-620) n = 16 13.1±2.21 n = 16 13.1±2.21 n = 16 12.2±1.68 n = 12 12.6±1.83 n = 16 221.3±43.4 n = 16 221.3±43.4 n = 16 192.5±34.3 n = 12 190.4±41.6 n = 16 208.4±101.8 n = 16 208.4±101.8 n = 16 149.2±36.1 n = 12 147±32.6 P value 0.88 (ns) 0.91 (ns) 0.54 (ns) 0.67 (ns) 0.039 (s) 0.09 (ns) 0.24 (ns) 0.57 (ns) 0.046 (s) 0.063 (ns) 0.041 (s) 0.036 (s) CS: cyclosporine, eGFR: estimated glomerular filtration rate, ITT: intention-to-treat population, MDRD: modification of diet in renal disease, ns: not significant, OT: on treatment, SD: standard deviation, SRL: sirolimus. Conflict of interest The authors declare the following conflicts of interest: - Dr. Gustavo Martínez Mier receives lecture fees from Pfizer, Roche and Novartis and consultancy fees from Novartis and Sanofi. 1. Nankivell BJ, Borrows RJ, Fung CL, O´Connel PJ, Allen RD, Chapman JR. The natural history of chronic alNefrologia 2014;34(4):526-44 lograft nephropathy. N Engl J Med 2003;349:2326-33. 2. Schena FP, Pascoe MD, Alberu J, del Carmen Rial M, Oberbauer R, Brennan DC, et al. Conversion from calcineurin inhibitors to sirolimus: maintenance therapy in renal allograft recipients: 24 months: efficacy and safety results from the CONVERT trial. Transplantation 2009;87:233-42. 3. Kreis H, Cisterne JM, Land W. Sirolimus in association with mycophenolate mofetil induction for the prevention of acute graft rejection in renal allograft re- cipients. Transplantation 2000;69:125260. 4. Flechner SM, Goldfarb D, Modlin C, Feng J, Krishnamurthi V, Mastroianni B, et al. Kidney transplantation without calcineurin inhibitor drugs: a prospective, randomized trial of sirolimus versus cyclosporine. Transplantation 2002;74:1070-6. 5. Hamdy AF, El-Agroudy AE, Bakr MA, Mostafa A, El-Baz M, El-Shahawy el-M, et al. Comparison of sirolimus with lowdose tacrolimus versus sirolimus based calcineurin inhibitor-free regimen in live 533 letters to the editor donor renal transplantation. Am J Transplant 2005;5:2531-8. 6. Ekberg H, Tedesco-Silva H, Demirbas A, Vítko S, Nashan B, Gürkan A, et al. Reduced exposure to calcineurin inhibitors in renal transplantation. N Engl J Med 2007;357:2562-75. 7. Flechner SM, Glyda M, Cockfield S, Grinyó J, Legendre Ch, Russ G, et al. The ORION study: comparison of two sirolimus-based regimens versus tacrolimus and mycophenolate mofetil in renal allograft recipients. Am J Transplant 2011;11(8):1633-44. 8. Martínez-Mier G, Mendez-Lopez MT, Budar-Fernandez LF, Estrada-Oros J, Franco-Abaroa R, George-Micelli E, et al. Living related kidney transplantation without calcineurin inhibitors: initial ex- perience in a Mexican center. Transplantation 2006;82(11):1533-6. 9. Martinez-Mier G, Mendez-Lopez Marco T, Budar-Fernandez LF, Avila-Pardo SF, Zamudio-Morales C. Living related kidney transplantation without calcineurin inhibitors: 3-year results of a randomized prospective trial in a Mexican center. (Poster presented at American Transplant Congress 2009, Boston, MA, USA). Am J Transplant 2009;79:s2:500 Abstract 1098. 10. Levey A, Greene T, Kusek J, Beck Gft MSG. A simplified equation to predict glomerular filtration rate for serum creatinine (Abstract). J Am Soc Nephrol 2000;11:155A. Gustavo Martínez-Mier1, Sandro F. Ávila-Pardo1, Marco T. Méndez-López2, Luis F. Budar-Fernández2, Benjamín Franco-Ahumada1, Felipe González-Velázquez3 1 Servicio de Trasplantes. IMSS UMAE 189 ARC. Hospital Regional de Alta Especialidad de Veracruz (Mexico); 2 Servicio de Trasplantes. IMSS UMAE 189 ARC. Veracruz (México); 3 Servicio de Investigación. IMSS UMAE 189 ARC. Veracruz (Mexico). Correspondence: Gustavo Martínez Mier Servicio de Trasplantes. IMSS UMAE 189 ARC, Hospital Regional de Alta Especialidad de Veracruz. Alacio Pérez, 928-314. Zaragoza, 91910. (Mexico). [email protected] [email protected] C) BRIEF CASE REPORT Hepatitis C virus infection, interferon α and lupus; a curious combination Nefrologia 2014;34(4):534-6 doi:10.3265/Nefrologia.pre2014.Apr.12349 To the Editor, Drug-induced lupus is a syndrome that shares clinical and analytical characteristics with idiopathic systemic lupus erythematosus and which appears after exposure to certain drugs that induce autoantibody formation. In 1945, Hoffman described the first case of drug-induced lupus, which involved the antibiotic sulfadiazine as the agent responsible for the condition. Eight years later, in 1953, Morrow et al. published a new case relating to the use of hydralazine1. Since then, the list of associated drugs has continued to increase and in recent years, biological therapies, such as tumour necrosis factors (TNF) and interferons (IFN), have joined with classic agents, such as procainamide, the aforementioned hydralazine, isoniazid or minocylcine2,3,4. 534 The mechanism causing this condition has not been fully defined; immunogenetic (certain HLA alleles) and pharmacogenetic (slow acetylator phenotype) factors appear to play an important role in its aethiopathogeny1,5. In terms of clinical presentation, the most common symptoms are fever, general malaise, muscle pain, joints pain, arthritis, rash and serositis. Unlike idiopathic lupus, kidney, haematologic and nervous system disorders are uncommon6. Antihistone antibodies are typical laboratory findings. Hypocomplementaemia and anti-double-stranded DNA, characteristics of idiopathic lupus, tend to be absent, although the latter can test positive in cases of anti-TNF- or IFN-induced lupus (Table 2). The interval of time between starting the drug and the condition appearing is highly variable, being between 2 weeks and 7 years in the case of IFN-α; a case developing two months after the drug’s suspension has been described7. This condition’s prognosis is favourable, such that discontinuation of the responsible drug is followed by recovery in the majority of cases, in a time frame that can stretch from weeks to months. Until then, non-steroidal anti-inflammatory drugs (NSAID), hydroxychloroquine and low-dose systemic corticosteroids can be used temporarily to control symptoms. CASE We present a 51-year-old male, with chronic kidney failure secondary to IgA glomerulonephritis, on a periodic haemodialysis programme, hypertensive, an ex-user of cocaine by inhalation and with chronic hepatitis C virus (HCV) disease, for which reason he was treated with ribavirin and pegylated IFN-α (180μg per week) for 49 weeks, obtaining a sustained viral response. Two weeks after finishing this treatment, he sought consultation due to asthenia and generalised joint pain of 10-15 days evolution, also experiencing in the last 48 hours 38 ºC fever and increased right hip pain. In the physical examination he presented pain on moving the aforementioned joint, with neither functional weakNefrologia 2014;34(4):526-44 letters to the editor Table 1. Medicines associated with drug-induced lupus4 Medicines definitively associated with drug-induced lupus Chlorpromazine Isoniazid Hydralazine Methyldopa Minocycline Procainamide Quinidine Medicines possibly associated with drug-induced lupus Acebutolol Phenylbutazone Para-aminosalicylic Acecainide Phenytoin Penicillamine Nalidixic acid Phenopyrazone Penicillin Adalimumab Fluvastatin Perazine Allopurinol Griseofulvin Perphenazine Aminoglutethimide Guanoxan Pyrathiazine Amoproxan Ibuprofen Pyridoxine Anthiomaline Infliximab Practolol Atenolol Interferon-α Promethazine Atorvastatin Interferon-γ Propafenone Benoxaprofen Interleukin-2 Propylthiouracil Captopril Labetalol Propranolol Carbamazepine Leuprolide Psoralen Chlorprothixene Levodopa Quinidine Chlorthalidone Levomepromazine Reserpine Cimetidine Lithium Simvastatin Cinnarazine Lovastatin Sulindac Clonidine Mephyton Sulfadimethoxine Danazol Mesalazine Sulfamethoxypyridazine Diclofenac Methimazole Sulfasalazine Diphenylhydantoin Methysergide Tetracyclines Disopyramide Methylthiouracil Tetracin Enalapril Metoprolol Thioamide Spironolactone Metrizamide Thioridazine Streptomycin Minoxidil Timolol Oestrogens Nitrofurantoin Tolazamide Etanercept Nomifensine Tolmetin Ethosuximide Oxyphenisatin Trimethadione Ethylphenacemide Oxprenolol Table 2. Characteristics of spontaneous and drug-induced lupus6 Clinical characteristics Constitutional symptoms Arthralgia and arthritis Pleuropericarditis Hepatomegaly Rash Kidney disease Central nervous system disorder Haematological abnormalities Immunological abnormalities - ANA - Anti-RNP - Anti-Sm - Anti-dsDNA - Antihistone - Complement Nefrologia 2014;34(4):526-44 Spontaneous lupus Drug-induced lupus 83% 90% 50% 25% 74% 53% 32% Common 50% 95% 50% 25% 10-20% 5% 0% Uncommon 95% 40-50% 20-30% 80% 60-80% Bajo 95% 20% Rare Rare 90-95% Normal ness nor inflammatory signs at this level nor in other joints. The increase of acute-phase reactants (C reactive protein was 9, ESR 120 and neutrophilia) stood out in the laboratory analysis. Blood cultures were taken (which were sterile) and, in order to rule out septic arthritis, an ultrasound of the joint was requested, which did not show signs of arthritis nor joint fluid on being drained and analysed. An echocardiogram ruled out endocarditis. In the study undertaken to rule out tumours/inflammation (bone scan, body gallium scan and chest/ abdominal/pelvic CT scan), degenerative changes were only observed in the scapulohumeral, glenohumeral and coxofemoral joints, with no other significant findings. The autoimmunity test was positive for ANA (IIF) at titres of 1:80 and anti-chromatin (antihistone), with negative anti-dsDNA and normal complement levels. Other findings were rheumatoid factor 29 and positive cryoglobulins (but with only 0.33% cryocrit). It must be mentioned that one year before, prior to starting treatment with pegylated IFN, autoimmunity was negative and by contrast, cryoglobulins were positive with 4.4% cryocrit. Given these results suggesting drug-induced lupus (related to the pegylated IFN-α that the patient had been receiving until two weeks before due to his HCV), treatment with NSAID, low dose corticosteroids and hydroxychloroquine was started, with significant improvement of symptoms. Lymphocyte populations were also counted before and during IFN-α therapy, showing significant lymphopenia, with a decrease of both T cells (CD4+ and CD8+) and B cells during treatment (Figure 1). DISCUSSION Drug-induced lupus is a condition without established diagnostic criteria. It should be considered in those patients who have received one of the implied drugs for longer than one month and who have compatible symp535 letters to the editor Pilar Auñón-Rubio, Eduardo Hernández-Martínez, Ángel Sevillano-Prieto, Enrique Morales-Ruiz Servicio de Nefrología. Hospital Universitario 12 de Octubre. Madrid. (Spain). Correspondence: Pilar Auñón Rubio Servicio de Nefrología. Hospital Universitario 12 de Octubre. Madrid. (Spain). [email protected] Cells/ml 1600 1400 1200 1000 800 600 400 200 0 Before starting IFN Total Lymphocytes CD8+ T cells During IFN treatment CD3+ lymphocytes CD19+ B cells CD4+ T cells Figure 1. Evolution of lymphocyte populations following treatment with interferon α. IFN: interferon. toms and autoimmunity test. The growing appearance of new pharmacological therapies, as well as the important pharmacosurveillance of their adverse effects, make the list of agents associated with this condition increasingly comprehensive. For this reason, high clinical suspicion is key, and therefore timing is of great importance. For our patient, significant lymphocyte depletion induced by IFN-α should also be noted. Although T cell lymphopenia is an effect already described with the use of IFN-α due to thymus’ function alteration, this situation, together with the patient’s significant B lymphopenia, would mean a dysregulation of the immune response which could be involved in autoimmunity. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 536 1. Hess E. Drug-related lupus. N Engl J Med 1988;318:1460-2. 2. Mongey AB, Hess EV. Drug insight: autoimmune effects of medications— what’s new? Nat Clin Pract Rheumatol 2008;4:136-44. 3. Fritzler MJ. Drugs recently associated with lupus syndromes. Lupus 1994;3(6):455-9. 4. Aguirre Zamorano MA, López Pedrera R, Cuadrado Lozano MJ. Lupus inducido por fármacos. Med Clin (Barc) 2010;135(3):124-9. 5. Adams LE, Mongey AB. Role of genetic factors in drug-related autoimmunity. Lupus 1994;3(6):443-7. 6. Schur PH, Massarotti EM. Lupus erythematosus: clinical evaluation and treatment. New York: Springer; 2012. pp. 211-21. 7. Wilson LE, Widman D, Dikman SH, Gorevic PD. Autoimmune disease complicating antiviral therapy for hepatitis C virus infection. Semin Arthritis Rheum 2002;32(3):163-73. 8. Beq S, Rozlan S, Pelletier S, Willems B, Bruneau J, Lelievre JD, et al. Altered thymic function during interferon therapy in HCV-infected patients. PLoS One 2012;7(4):e34326. Baclofen neurotoxicity in a patient with end-stage chronic renal failure Nefrologia 2014;34(4):536-8 doi:10.3265/Nefrologia.pre2014.Apr.12320 To the Editor, Baclofen (4-beta-chlorophenyl-gamma-aminobutyric acid) is a muscle relaxant, used as an antispasmodic in diseases such as multiple sclerosis, medullary trauma and hiccups 1,2 . It is mainly excreted through the kidneys (69%-85%) and has a 2 to 6 hr. half life in healthy people. There is a high risk of neurotoxicity in patients with renal failure, especially if administered with <30ml/min glomerular filtration rate, causing episodes of unconsciousness 3,4 . Baclofen intoxication in dialysis patients is rare, with very diverse forms of clinical presentation 5-9 . We present the clinical case of a patient with baclofen-induced encephalopathy, with atypical clinical evolution; symptoms did not improve with haemodialysis and the patient went into complete remission following the drug’s discontinuation. Nefrologia 2014;34(4):526-44 letters to the editor CASE DESCRIPTION We present a 31-year-old patient with traumatic spinal injury at 20 and a history of repeated urinary infections related to neurogenic bladder (selfcatheterisation) and episodes of urinary obstruction. In 2009 he was referred to the nephrology department due to stage 2 chronic kidney disease, with nephrotic-range proteinuria (1.3mg/dl creatinine, 20g/24h proteinuria). The patient refused renal biopsy and in the same year, he stopped attending nephrology consultations. In January 2012 he started experiencing episodes of deteriorating levels of consciousness. Cranial computerised tomography and lumbar puncture were performed, both with normal results. Electroencephalogram showed diffuse slowing. At that time, creatinine was 3.3mg/dl. The clinical profile was suggested as secondary to urinary infection. The same symptoms repeated in April 2012, accompanied by spatial and time disorientation. He presented a new episode in the same month, but this time with behavioural change (infantilism, nervousness, aggressiveness). Cerebral MRI was unremarkable. Following this episode, treatment with clonazepam was started. In May 2012, due to end-stage renal failure analysis results and symptoms, haemodialysis was started using a temporary catheter in the right jugular vein. Approximately once a month, in the first two hours after starting dialysis, the patient experienced episodes of reduced levels of consciousness and, at times, psychomotor agitation. The patient was evaluated in November 2012 by the Neurology and Psychiatry department, with no relevant findings. They diagnosed the condition as secondary to hypoxic metabolic encephalopathy. Nefrologia 2014;34(4):526-44 Despite presenting correct KT and Kt/V, we increased the number of dialysis sessions to 4/week, without clinical improvement. the drug’s excretion, baclofen’s half life went from 15.5h in patients with stage 5 chronic renal failure not on dialysis to 2.06h in dialysis patients11-13. In January 2013, we decided to suspend treatment with baclofen (Lioresal®), replacing it with tizanidine and diazepam. After two weeks of tizanidine treatment, the patient stopped the drug because of drowsiness and spasticity was controlled only with diazepam. We suspect that this patient’s clinical symptoms can be attributed to a sudden suppression of baclofen levels in blood. It is worth noting that similar cases have been described in sudden withdrawals of this drug in patients with intrathecal perfusions.14,15 10 months after the drug’s discontinuation, the patient had not re-experienced neurological symptoms. DISCUSSION Spasticity is a classic symptom in spinal injury patients. Baclofen is widely used in these patients, despite their high risk of neurotoxicity, as a result of having reduced renal function due to neurogenic bladder. We also have to bear in mind that, on assessing serum creatinine levels, we overestimated the renal function due to a decrease in muscular mass10. Psychomotor agitation is a rare symptom of baclofen-induced encephalopathy. This encephalopathy usually manifests itself as a reduced level of consciousness. Our patient initially presented this symptom, since the same baclofen dose was used as in a patient with normal renal function. Following deterioration in renal function and the start of haemodialysis, the patient experienced the atypical symptom of psychomotor agitation. In reviewing the literature, we observe that the pharmaco-dynamics of baclofen in dialysis patients is expressed as C = C0 + eKet, where Ke is dependent on the drug’s renal (Kr) and non-renal (Knr) metabolism. In dialysis patients, renal clearance is restricted to clearance during dialysis; thus Kr = Kd, where Kd = 0.291/h and Knr 0.045/h, therefore Ke = Kd + Knr = 0.336/h. Given Despite no clear indications about baclofen in pharmacological guides, we do not recommend the use of this drug in dialysis patients. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1. Peces R, Navascués RA, Baltar J, Laurés AS, Alvarez-Grande J. Baclofen neurotoxicity in chronic haemodialysis patients with hiccups. Nephrol Dial Transplant 1998;13(7):1896-7. 2. Chou CL, Chen CA, Lin SH, Huang HH. Baclofen-induced neurotoxicity in chronic renal failure patients with intractable hiccups. South Med J 2006;99(11):1308-9. 3. Su W, Yegappan C, Carlisle EJ, Clase CM. Reduced level of consciousness from baclofen in people with low kidney function. BMJ 2009;339:b4559. 4. Chen KS, Bullard MJ, Chien YY, Lee SY. Baclofen toxicity in patients with severely impaired renal function. Ann Pharmacother 1997;31(11):1315-20. 5. Hsieh MJ, Chen SC, Weng TI, Fang CC, Tsai TJ. Treating baclofen overdose by hemodialysis. Am J Emerg Med 2012;30(8):1654.e5-7. 6. Dias LS, Vivek G, Manthappa M, Acharya RV. Role of hemodialysis in baclofen overdose with normal renal function. Indian J Pharmacol 2011;43(6):722-3. 7. Bassilios N, Launay-Vacher V, Mercadal L, Deray G. Baclofen neurotoxicity [correction of unerotoxicity] in a chronic haemodialysis patient. Nephrol Dial Transplant 2000;15(5):715-6. 8. Himmelsbach FA, Köhler E, Zanker 537 letters to the editor B, Wandel E, Krämer G, Poralla T, et al. [Baclofen intoxication in chronic hemodialysis and kidney transplantation]. Dtsch Med Wochenschr 1992;117(19):733-7. 9. Seyfert S, Kraft D, Wagner K. [Baclofen toxicity during intermittent renal dialysis (author’s transl)]. Nervenarzt 1981;52(10):616-7. 10.El-Husseini A, Sabucedo A, Lamarche J, Courville C, Peguero A. Baclofen toxicity in patients with advanced nephropathy: proposal for new labeling. Am J Nephrol 2011;34(6):491-5. 11.Chen YC, Chang CT, Fang JT, Huang CC. Baclofen neurotoxicity in uremic patients: is continuous ambulatory peritoneal dialysis less effective than intermittent hemodialysis? Ren Fail 2003;25(2):297-305. 12.Brvar M, Vrtovec M, Kovac D, Kozelj G, Pezdir T, Bunc M. Haemodialysis clearance of baclofen. Eur J Clin Pharmacol 2007;63(12):1143-6. 13. Wu VC, Lin SL, Lin SM, Fang CC. Treatment of baclofen overdose by haemodialysis: a pharmacokinetic study. Nephrol Dial Transplant 2005;20(2):4413. 14.Karol DE, Muzyk AJ, Preud’homme XA. A case of delirium, motor disturbances, and autonomic dysfunction due to baclofen and tizanidine withdrawal: a review of the literature. Gen Hosp Psychiatry 2011;33(1):84.e1-2. 15. Salazar ML, Eiland LS. Intrathecal baclofen withdrawal resembling serotonin syndrome in an adolescent boy with cerebral palsy. Pediatr Emerg Care 2008;24(10):691-3. Pablo Justo-Ávila, Luciemne Fernández-Antuña, M. Teresa Compte-Jove, Cristina Gállego-Gil Sección de Nefrología. Hospital de la Santa Creu. Tortosa, Tarragona. (Spain). Correspondence: Pablo Justo Ávila Sección de Nefrología. Hospital de la Santa Creu. Avda. Mossèn Valls, 1. 43590. Tortosa, Tarragona. (Spain). [email protected] [email protected] 538 Achromobacter xylosoxidans in two haemodialysis patients Nefrologia 2014;34(4):538-9 doi:10.3265/Nefrologia.pre2014.May.12141 To the Editor, Achromobacter (alcaligenes) xylosoxidans (AX) is a gram-negative, aerobic bacillus, carried by animals (rabbits, ferrets), although it is also present in normal human flora, especially of the skin and gastrointestinal tract1. It is an opportunistic bacterium with low virulence, except in immunocompromised patients, in whom it can cause serious infections such as meningitis, endocarditis and, most commonly, bacteraemia2. Patients with a catheter are more likely to develop AX and it is more frequent in peritoneal dialysis (PD) than haemodialysis (HD) patients, where there are few published cases; all cases are associated with a central venous catheter (CVC)3-5. Contamination of the catheter, the heparin multi-dose vials, the antiseptic solutions and the dialysate itself have been described as possible sources of infection, and the clothes or hands of the health staff as methods of transmission5. new catheterisations due to infections of the catheter entry site). The patient was admitted due to fever and shivers following dialysis, symptoms compatible with bacteraemia, with positive blood cultures of Staphylococcus (St.) aureus. There was associated infection in the catheter entry site, for which reason the catheter, which was cultured and resulted positive for AX, St. aureus and Enterococcus faecalis, was removed. The clinical and bacteriological infectious condition disappeared with combined treatment of the three bacteria. CASE 2 A 46-year-old male patient, hypertensive, with hyperuricemia and CKD possibly secondary to chronic glomerulonephritis (GN), on HD since 1995. He received two cadaveric kidney transplants, with possible early recurrence of membranous GN and restarted HD in 2004. CASE 1 The patient was a 67-year-old female, from Bulgaria, hypertensive, diabetic, obese, with dyslipidaemia and chronic kidney disease (CKD) possibly secondary to diabetes and/or nephroangiosclerosis, on HD since January 2008. Low socioeconomic status, living with animals and bad personal hygiene. The patient had multiple vascular accesses, the last being left humero-axillary prosthetic AVF (polytetrafluoroethylene), which resulted in ulceration on the skin close to the anastomosis with serous secretion, leaving the prosthesis exposed. A temporary CVC was implanted and a culture, growing AX, was taken from the ulcer. The patient did not show increase of acute phase reactants nor systemic infection data. He received intravenous antibiotics according to the antibiogram, after which the culture was repeated, with development of AX continuing. He received new courses of antibiotics, without managing to eradicate the bacterium (three AX positive cultures). Thus, surgical removal of the prothesis was decided upon and the implanting of a new vascular access (femoral saphenous AVF). The culture after the surgical wound tested negative for AX. Left humeral-cephalic arteriovenous fistula (AVF) was performed, with slow recovery, carrying out HD using a temporary CVC (multiple removals and CONCLUSIONS Although AX is not a common bacterium, it can be seen in HD patients. We present two cases of AX that occurred in our department on the same date in patients undergoing the same HD session. Nefrologia 2014;34(4):526-44 letters to the editor In case 1, the patient had multiple factors for developing AX infection: contact with animals, poor socioeconomic conditions, poor personal hygiene and having a CVC. For these reasons, we think that it was the primary focus of the infection. The removal of the catheter and specific antibiotic treatment resolved the bacteraemia. In case 2, colonisation of the prothesis could be due to transmission by the clothes or hands of the healthcare staff, since multi-dose vials were not used, nor were there other infections in the unit that could be associated with contamination of the dialysate. In this instance, as expected, the bacterium was not eradicated until removing the prosthetic material, despite receiving various courses of antibiotics according to the antibiogram. In addition, it is the first case described in the literature on fistula contamination by AX. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1. Ahmed MS, Nistal C, Jayan R, Kuduvalli M, Anijeet HK. Achromobacter xylosoxidans, an emerging pathogen in catheter-related infection in dialysis population causing prosthetic valve endocarditis: a case report and review of literature. Clin Nephrol 2009;71(3):350-4. 2. Al-Jasser AM, Al-Anazi KA. Complicated septic shock caused by Achromobacter xylosoxidans bacteraemia in a patient with acute lymphoblastic leukaemia. Libyan J Med 2007;2(4):218-9. 3. Turgutalp K, Kiykim A, Ersoz G, Kaya A. Fatal catheter-related bacteraemia due to Alcaligenes (Achromobacter) Xylosoxidans in a haemodialysis patient. Int Urol Nephrol 2012;44(4):1281-3. 4. Nalek-Marín T, Arenas MD, Perdiguero M, Salavert-Lleti M, Moledous A, Cotilla E, et al. A case of endocarditis of difficult diagnosis in dialysis: could “pest” friends be involved? Clin Nephrol 2009;72(5):405-9. 5. T ena D, Carranza R, Barberá JR, Valdezate S, Garrancho JM, Arranz M, et al. Outbreak of long-term intravascular catheterNefrologia 2014;34(4):526-44 related bacteraemia due to Achromobacter xylosoxidans subspecies xylosoxidans in a haemodialysis unit. Eur J Clin Microbiol Infect Dis 2005;24(11):727-32. M. Eugenia Palacios-Gómez, Adoración Martín-Gómez, Sergio García-Marcos Unidad de Nefrología. Hospital de Poniente. El Ejido, Almería. (Spain). Correspondence: M. Eugenia Palacios Gómez Unidad de Nefrología. Hospital de Poniente. Carretera de Almerimar, S/N. 04700, El Ejido, Almería. (Spain). [email protected] [email protected] Methylmalonic acidemia with homocystinuria. A very rare cause of kidney failure in the neonatal period Nefrologia 2014;34(4):539-40 doi:10.3265/Nefrologia.pre2014.May.12058 To the Editor, Methylmalonic acidemia with homocystinuria (MMAH) is a rare congenital metabolic and heterogeneous disorder affecting vitamin B12 or cobalamin (cbl) metabolism. The disorder causes a reduction in the levels of adenosyl and methylcobalamin coenzymes, in turn reducing the activity of their respective enzymes, methylmalonyl-CoA mutase and methionine synthase. This results in the accumulation of methylmalonic acid and homocysteine in the blood and tissues, with an increase in the urinary excretion of both compounds1. Various forms of the disease have been described: cblC, cblD and cblF. Neonatal presentation of this condition includes failure to thrive, encephalopathy, psychomotor retardation, haematological abnormalities of the three series and renal damage1. We present two cases diagnosed in our department, who died from atyp- ical haemolytic uraemic syndrome (HUS) associated with severe kidney failure. The first case was a 25-day-old male, admitted due to bilious vomiting and liquid bowel movements which had started four days earlier. He was the second son of first-cousin parents. On admission he presented mild malnutrition, hypotonia and hypoactivity. He had normochloraemic metabolic acidosis. Following slight improvement on being subjected to complete fasting, feeding was started; poor tolerance, neurological deterioration, pancytopenia and liver and renal failure were observed. Subsequently, on initiating parenteral nutrition, microangiopathic anaemia was reported together with increased thrombocytopenia (haemoglobin 6.7 g/l, platelets 10,000/mm3) and worsening of renal failure. Atypical HUS was diagnosed. In addition, he experienced various convulsive episodes, with encephalopathic findings in the electro-encephalogram. He died 20 days after admission with severe kidney failure (creatinine 1.3mg/dl, urea 193mg/dl, potassium 6.6mEq/l). The second case was a 24-day-old male, who was taken to hospital due to 7% weight loss following birth, hypotonia and general malaise. The parents were also first cousins. He was admitted with a diagnosis of suspected sepsis (increase of acute-phase reactants and positive haemoculture for coagulase-positive staphylococcus). He also had normochloraemic metabolic acidosis. Antibiotics were prescribed and the patient continued with complete fasting, with good clinical response. Poor tolerance, respiratory difficulty, neurological deterioration, pancytopenia and liver failure were observed on beginning nutrition. At that time, he was diagnosed with dilated myocardiopathy with reduced ejection fraction, which normalised after suspending 539 letters to the editor nutrition. Parenteral nutrition was subsequently started, when kidney failure occurred (oligoanuria, creatinine 1mg/ dl, urea 90mg/dl), accompanied by anaemia and thrombopenia (haemoglobin 7.7g/l, platelets 21,000/mm3). Therefore, continuous venovenous haemofiltration was started. Although the presence of schistocytes was unknown, we suspected that he suffered from atypical HUS. Cerebral echography showed severe cortical atrophy. 30 days after admission the diagnosis of methylmalonic acidemia with homocystinuria was confirmed. Given the unfavourable prognosis, we decided upon a limitation of therapeutic effort. The most noteworthy data from the metabolic and genetic study of both patients, required for diagnosis, are shown in Table 1. Our patients were suffering from the most common variant of the disease (cblC), which is caused by homozygous or compound heterozygous mutations in the MMACHC gene [methylmalonic aciduria (cobalamin deficiency) cblC type, with homocystinuria], which is located on the 1p34 chromosome. A symptom-free period is typical in methylmalonic acidemia with homocystinuria, since for clinical symptoms to appear, protein intake is required, with the consequential accumulation of methylmalonic acid and homocysteine. This explains why, in our patients, deterioration was observed on restarting feeding, whether enteral or parenteral. At times, there was a larvate clinical sign which was precipitated by intercurrent disease, often an infection, as occurred in case 2. Dilated myocardiopathy (case 2) is also described as a complication, of which a case diagnosed prenatally was reported2, as well as other cardiac disturbances in relation to thromboembolisms. The pathogenesis of thrombotic microangiopathy is related to the increase of plasma methylmalonic acid and homocysteine levels. The latter modifies the vascular endothelial’s antithrombatic properties by interfering in the inhibition of platelet aggregation mediated by nitric oxide, which favours the union of the tissue plasminogen activator with the endothelial. This results in an increase of the endothelial expression of procoagulants. In addition, homocysteine thiolactone, homocysteine metabolite, can cause cell damage by inducing intracellular accumulation of free radicals and methylmalonic acid can interfere in the mitochondrial metabolism of renal cells. Association with HUS is uncommon, although described, above all, in newborns3,4, as was confirmed in case 1 and suspected in case 2. At birth, many patients already have kidney failure, which could be reversible with early treatment (hydroxocobalamin, trimethylglycine, folate and protein restriction), which did not occur in our cases given the late diagnosis4,5. Consequently, early clinical suspicion is fundamental for trying to improve renal function as much as possible. Homozygous mutation in MMACHC gene (type cblC) 540 Orlando Mesa-Medina, Mónica Ruiz-Pons, Víctor García-Nieto, José León-González, Santiago López-Mendoza, Carlos Solís-Reyes Departamento de Pediatría. Hospital Universitario Nuestra Señora de Candelaria. Santa Cruz de Tenerife. (Spain). Correspondence: Orlando Mesa Medina Departamento de Pediatría. Hospital Universitario Nuestra Señora de Candelaria. Santa Cruz de Tenerife. (Spain). [email protected] Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. Table 1. Biochemical and genetic data Case 1 Methylmalonic acid (urine) 124mmol/mol Cr Normal: 0.8-8.5mmol/mol Cr Homocysteine (serum) Normal: 3.7-7.5mcmol/l 1. Deodato F, Boenzi S, Rizzo C, Dionosi-Vici C. The clinical picture of early-onset cobalamin C defect (methylmalonic aciduria and homocystinuria). Pediatr Child Health 2008;18:S57-60. 2. De Bie I, Nizard SD, Mitchell GA. Fetal dilated cardiomyopathy: an unsuspected presentation of methylmalonic aciduria and hyperhomocystinuria, cblC type. Prenat Diagn 2009;29:266-70. 3. Rogé Canales M, Rodrigo Gonzalo de Liria C, Prats Viñas LJ, Vaquero Pérez M, Ribes Rubió A, Rodés Monegal M, et al. Síndrome hemolítico-urémico neonatal asociado a aciduria metilmalónica y homocistinuria. An Esp Pediatr 1996;45:97-8. 4. Menni F, Testa S, Guez S, Chiarelli G, Alberti L, Esposito S. Neonatal atypical hemolytic uremic syndrome due to methylmalonic aciduria and homocystinuria. Pediatr Nephrol 2012;27:1401-5. 5. Huemer M, Simma B, Fowler B, Suormala T, Bodamer OA, Sass JO. Prenatal and postnatal treatment in cobalamin C defect. J Pediatr 2005;147:469-72. Case 2 2150mmol/mol Cr 85mcmol/l 109mcmol/l c.271dupA/c.271dupA c.271dupA/c.271dupA An uncommon cause of linfadenopathy in a kidney transplant patient: Cat-scratch disease Nefrologia 2014;34(4):540-2 doi:10.3265/Nefrologia.pre2014.May.12474 Dear Editor, Cat scratch disease (CSD) is an infectious disease that usually presents Nefrologia 2014;34(4):526-44 letters to the editor as a self-limiting illness characterized by regional lymphadenopathy, fever and constitutional symptoms in association with a cat scratch or bite.1-4 In most cases, Bartonella henselae is the etiologic agent and cats are important reservoirs.2-5 We report a case of CSD in a 38-yearold Caucasian female recipient of a deceased kidney transplant since 2006 due to chronic renal failure of unknown etiology. Her maintenance immunosuppressive treatment was mycophenolate mofetil and cyclosporine. She was also medicated with calcium carbonate, vitamin D, atenolol, folic acid, fluoxetine, omeprazole, ferrous sulfate. Six years post transplantation the patient was admitted to the hospital with a 4-week history of asthenia, low fever, loss of weight and multiple painful cervical ganglions. There was no previous history of tuberculosis. She had close contact at home with cats. On physical examination, the patient had a temperature of 37,3ºC, pulse rate of 84/min, blood pressure of 134/88mmHg, respiratory rate of 16/ min and pulse oximetry of 100% in ambient air. She had multiple bilateral painful ganglions only in cervical region (node size ≤4cm). There was no rash. Examination of the lungs, heart and abdomen revealed no abnormalities including hepatosplenomegaly. The graft was painless. Laboratory tests revealed a white blood cell count 11,81×10^3/L (neutrophils 65,8%, lymphocytes 23,6%, monocytes 10%, eosinophils 0,1%), normochromicnormocytic anemia (Hgb 9,6g/dL); creatinine 1,2mg/dL (basal value), blood urea nitrogen 39mg/dL; protein C reactive 143mg/L; LDH, SGOT, SGPT, total bilirubin and alkaline phosphate without alterations. Ultrasound cervical ecography demonstrated multiple ganglion formations. She was observed on admission by an otorhinolaryngologist who prescribed metronidazole plus amoxicillin and clavulanate for a nasopharynx´s infection. Serologies for Epstein-Barr Nefrologia 2014;34(4):526-44 internment (without improvement of complains) and began azithromycin 500mg on day one, followed by 250mg for four days. There has been a good clinic improvement with involution of ganglion swelling and resolution of the pain and fever. One month later the patient was asymptomatic, without any signs of recurrence. Figure 1. Ganglion biopsy – Focus of necrosis, some surrounded by granulomatous inflammation in cortical region (H&E, original magnification x40). virus, herpes virus, cytomegalovirus, toxoplasmosis, brucella, leishmania, and HIV infection were negative. Blood culture was sterile. Chest and abdominal CT scan without changes. Quantiferon test for tuberculosis was indeterminate. Peripheral blood cytometry and cytometry of ganglion did not showed immunophenotypic alterations compatible with lymphoma. An ganglion biopsy was performed and histological examination revealed reactive lymphadenitis with central necrosis (Ziehl neelsen was negative) alterations compatible with CSD (Figures 1 and 2). She stopped the initial antibiotherapy on the 6th of Figure 2. Ganglion biopsy – Focus of stellate aspect necrosis with epithelioid macrophages in the periphery (H&E, original magnification x100). This case report intends to illustrate that the investigation of an immunocompromised kidney transplant patient presenting with lymphadenopathy may constitute a challenge given the wide differential diagnosis possible. The presence of enlarged lymph nodes in those patients should lead to post-transplant lymphoproliferative disorders (PTLD) as a first hypothesis; however more benign and unsuspected causes must be the cause. The risk of PTLD is associated with the degree of immunosupression, time post transplant and the presence of Epstein-Barr virus.6-9 Their incidence is approximately 30 to 50 times greater than in the general population and comprises a wide histological spectrum from hyperplastic appearing lesions, non-Hodgkin lymphoma or multiple myeloma histology.6,8 Regional lymphadenopathy is the hallmark of CSD in association with mild constitutional symptoms and a previous history of cat scratch or bite.1-3 In our case the investigation was wide and extensive once this disease can mimic the more common PTLD disease or others infectious causes.2-4 In addition to serological tests a lymph node biopsy was performed to exclude lymphoma or other malignant causes. It has been proposed that at least three of four criteria must be present to establish the diagnosis of CSD: a) cat or flea contact; b) negative serology for other causes of adenopathy or sterile pus aspirated from a node or a positive Bartonella PCR assay or liver or spleen lesions on CT scan; c) positive serology for Bartonella henselae (EIA or IFA≥1:64); d) biopsy showing granulomatous 541 letters to the editor inflammation consistent with CSD or a positive Warthin-Starry silver stain.2,3,10 The diagnosis of CSD in our patient was based on the presence of a cat contact history, negative serology for other causes and a ganglion biopsy compatible with CSD (Figures 1 and 2). Serologic methods for detection of Bartonella henselae were not available in our hospital and it was not possible to isolate this agent by culture. The treatment of this entity is recommended in immunocompromised patients due to high risk for disseminated and recurrent CSD.2,3 Although CSD had rarely been reported in kidney transplant patients it should be considered in the differential diagnosis of patients with lymphadenopathy and a history of cat exposure.5 The absence of easy complementary tests, the difficulty in isolating the bacteria and the need of tissue biopsy makes a difficult diagnosis. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1. Spach D, Kaplan S. Treatment of cat scratch disease. Available at: www.uptodate.com (accessed in 01/10/2013). 2. Spach D, Kaplan S. Microbiology, epidemiology, clinical manifestations, and diagnosis of cat scratch disease. Available at: www.uptodate.com (accessed in 01/10/2013). 3. Lamps L, Scott M. Cat-scratch disease. Historic, clinical, and pathologic perspectives. Am J Clin Pathol 2004;121 Suppl:S71-80. 4. Goral S, Scott M, Dummer S, Miller G, Antony S, Helderman J. Cat-scratch disease in a patient undergoing haemodialysis. Nephrol Dial Transplant 1997;12:811-4. 5. Rheault MN, van Burik, Mauer M, Ingulli E, Ferrieri P, Jessurun J, et al. Cat-scratch disease relapse in a kidney transplant recipient. Pediatr Transplant 2007;11(1):105-9. 6. Newstead C. Lymphoproliferative disease post-renal transplantation. Nephrol Dial Transplant 2000;15:1913-6. 7. Quinlan S, Pleiffer R, Morton L, Engels E. Risk factors for early-onset and late-onset 542 post-transplant lymphoproliferative disorder in U.S. kidney recipients. Am J Hematol 2011;86(2):206-9. 8. Friedberg J, Aster J. Epidemiology, clinical manifestations, and diagnosis of post-transplant lymphoproliferative disorders. Available at: www.uptodate.com (acceded in 01/10/2013). 9. Caillard S, Dharnidharka V, Agodoa L, Bohen E, Abbott K. Posttransplant lymphoproliferative disorders after renal transplantation in the United States in era of modern immunosuppression. Transplantation 2005;80:1233-43. 10. Souza G. Cat scratch disease: case report. Rev Med Minas Gerais 2011;21(1):75-8. Cláudia Bento1, La Salete Martins2, André Coelho3, Manuela Almeida2, Sofia Pedroso2, Leonídeo Dias2, Ramon Vizcaíno3, António Castro-Henriques2, António Cabrita2 1 Department of Nephrology. Centro Hospitalar de Trás-os-Montes e Alto Douro. Vila Real (Portugal); 2 Department of Nephrology. Hospital Geral de Santo António. Porto (Portugal); 3 Department of Clinical Pathology. Hospital Geral de Santo António. Porto (Portugal). Correspondence: Claudia Bento Department of Nephrology. Centro Hospitalar de Trás-os-Montes e Alto Douro. Vila Real (Portugal) [email protected] Extreme hypocalcaemia and hyperparathyroidism following denosumab. Is this drug safe in chronic kidney disease? Nefrologia 2014;34(4):542-4 doi:10.3265/Nefrologia.pre2014.Mar.12383 To the Editor, Nefrología has recently published a case of post-denosumab hypocalcaemia and we would like to contribute to this subject 1. Denos- umab is an anti-RANKL (receptor activator of nuclear factor-κ B ligand) monoclonal antibody used in osteoporosis treatment as an antiresorptive agent. Unlike bisphosphonates, denosumab does not appear to be nephrotoxic 2, nor does it require dosage adjustments in kidney failure due to its favourable pharmacokinetic and pharmacodynamic profile 1,3. However, the qualitative bone changes in osteoporosis patients are not comparable with the wide spectrum of alterations in bone turnover that accompanies chronic kidney disease (CKD) 4. For this reason and in relation to the changes in mineral metabolism caused by denosumab, its safety in this population could be questioned. We describe a patient with advanced CKD with extreme hypocalcaemia and hyperparathyroidism following continuous administration of denosumab. The patient is a 75-year-old female who sought treatment for tremors, muscle spasms and paraesthesia in the limbs. Stage 5 CKD, probably secondary to nephroangiosclerosis and diabetes mellitus, stands out in her medical history. She is allergic to penicillin and is treated with insulin, doxazosin, nifedipine GITS, torsemide, acetylsalicyclic acid, oral iron, erythropoietin, paricalcitol and calcifediol. She was treated, until 7 months before, with 70mg alendronic acid, which was suspended on starting six-monthly subcutaneous 60mg denosumab. Her nephrologist was unaware of the prescription of this drug. She presented the following analysis: creatinine 3.6mg/dl, total corrected calcium 10.06mg/dl, ionic calcium 5.1mg/dl, phosphate 5.1mg/ dl, alkaline phosphatase 157U/l, bicarbonate 27.6mmol/l, parathyroid hormone (PTH) 436pg/ml, 25-vitamin D 30.2ng/ml. The evolution of the biochemical parameters until the last analysis 14 days after denosumab is shown in Figure 1. The patient did not attend this last evaluation due to not feeling well. Six days later, Nefrologia 2014;34(4):526-44 letters to the editor 20 18 16 14 12 10 8 6 4 Parenteral post-correction 2 0 Denosumab 60 May Corrected calcium August Denosumab 60 October Phosphorus November PTH (X 100) December Alkaline phosphatase (X 10) Figure 1. Evolution of biochemical parameters. PTH: parathyroid hormone she was examined in the Emergency Department: urea 154mg/dl, 6mg/dl creatinine, 4.36mg/dl total corrected calcium, 2.4mg/dl ionic calcium, 6.7mg/dl phosphate, 1.3mg/dl magnesium, 59U/l alkaline phosphatase, 18.6mmol/l bicarbonate, 1900pg/ ml PTH. Electrocardiogram (ECG): 440ms corrected QT (QTc). Oral and intravenous calcium replacement and intravenous calcitriol were started, with the disappearance of symptoms. After 15 days of parenteral replacement, the analytical parameters had normalised (Figure 1): ECG: QTc 402ms. PTH remained 1858pg/ml. The recommendations for the use of denosumab in kidney failure are based on a clinical trial involving very few patients, over a 16 week follow-up period and following only one dose of the drug 3. In addition, the authors excluded, in part of the study, those subjects with 1.25-dihydroxyvitamin D levels <30pg/ ml, severe renal failure and PTH ≥110pg/ml or kidney failure and PTH ≥300pg/ml. Even so, 22%-25% of the cases with moderate-severe Nefrologia 2014;34(4):526-44 renal failure or patients on dialysis presented hypocalcaemia. The authors recommend calcium and vitamin D supplements for its prevention. In another clinical trial carried out over 36 months in post-menopausal women with CKD and estimated glomerular filtration rate >15ml/min, cases of hypoparathyroidism, hyperparathyroidism, hypercalcaemia and hypovitaminosis D were excluded; PTH levels were not monitored in the study 2. In recent months, cases of hypocalcaemia in chronic nephropathies have continued to be reported 1,5-8. Non previous biphosphonate use and kidney failure are risk factors for developing hipocalcaemia 8. Consequently, our patient may only have developed hypocalcaemia following the second dose, since she had previously been treated with alendronate. Denosumab reduces the number of osteoclasts and bone formation rate. Hypocalcaemia would be related to the rapid mineral deposit of calci- um in the new bone matrix, which would behave similarly to a hungry bone following parathyroidectomy3. However, as occurred in this case, PTH was not suppressed, but hyperstimulated. In addition to sudden hypocalcaemia following the second denosumab dose, PTH levels were progressively increasing to very high levels following the first dose, despite vitamin D supplements; we also observed a reduction of alkaline phosphatase. For some experts, this inhibition of osteoclastogenesis could favour adynamic bone disease in CKD 4,5. The monitoring of calcium levels 8-14 days after treatment has been advised 7. However, this does not guarantee its prevention, since it is not known when the nadir is reached 7. Denosumab can cause potentially fatal short-term adverse effects, as well as other unknown long-term effects, on the bone of CKD patients. For these reasons, some authors recommend not using denosumab in CKD patients or only using it if a bone biopsy has previously been carried out 4,6. Conflict of interest The authors declare that they have no conflicts of interest related to the contents of this article. 1.Martín-Baez IM, Blanco-García R, Alonso-Suárez M, Cossio-Aranibar C, Beato-Coo LV, Fernández-Fleming F. Severe hypocalcaemia postdenosumab. Nefrologia 2013;33:6145. 2. Jamal SA, Ljunggren O, StehmanBreen C, Cummings SR, McClung MR, Goemaere S, et al. Effects of denosumab on fracture and bone mineral density by level of kidney function. J Bone Miner Res 2011;26:1829-35. 3. Block GA, Bone HG, Fang L, Lee E, Padhi D. A single-dose study of denosumab in patients with various degrees of renal impairment. J Bone Miner Res 2012;27:1471-9. 543 letters to the editor 4. Ott SM. Therapy for patients with CKD and low bone mineral density. Nat Rev Nephrol 2013;9:681-92. 5. Torregrosa JV. Dramatic increase in parathyroid hormone and hypocalcemia after denosumab in a kidney transplant patient. Clin Kidney J 2013;6:122. 6. McCormick BB, Davis J, Burns KD. Severe hypocalcemia following denosumab injection in a hemodialysis patient. Am J Kidney Dis 2012;60:626-8. 544 7. Farinola N, Kanjanapan Y. Denosumabinduced hypocalcaemia in high bone turnover states of malignancy and secondary hyperparathyroidism from renal failure. Intern Med J 2013;43:12436. 8. Okada N, Kawazoe K, Teraoka K, Kujime T, Abe M, Shinohara Y, et al. Identification of the risk factors associated with hypocalcemia induced by denosumab. Biol Pharm Bull 2013;36:1622-6. Ana E. Sirvent, Ricardo Enríquez, María Sánchez, César González, Isabel Millán, Francisco Amorós Servicio de Nefrología. Hospital General Universitario de Elche. Alicante. (Spain). Correspondence: Ana E. Sirvent Servicio de Nefrología. Hospital General Universitario de Elche. Camí de l’ Almàssera 11. 03203 Alicante. (Spain). [email protected] [email protected] Nefrologia 2014;34(4):526-44