title: Creatinine- versus cystatine C-based equations in assessing the renal function of candidates for liver transplantation with cirrhosis.
abstract: Renal dysfunction is frequent in liver cirrhosis and is a strong prognostic predictor of orthotopic liver transplantation (OLT) outcome. Therefore, an accurate evaluation of the glomerular filtration rate (GFR) is crucial in pre-OLT patients. However, in these patients plasma creatinine (Pcr) is inaccurate and the place of serum cystatine C (CystC) is still debated. New GFR-predicting equations, based on standardized assays of Pcr and/or CystC, have been recently recommended in the general population but their performance in cirrhosis patients has been rarely studied. We evaluated the performance of the recently published Chronic Kidney Disease Epidemiology Collaboration equations (CKD-EPI-Pcr, CKD-EPI-CystC, and CKD-EPI-Pcr-CystC) and the more classical ones (4- and 6-variable MDRD and Hoek formulas) in cirrhosis patients referred for renal evaluation before OLT. Inulin clearance was performed in 202 consecutive patients together with the determination of Pcr and CystC with assays traceable to primary reference materials. The performance of the GFR-predicting equations was evaluated according to ascites severity (no, moderate, or refractory) and to hepatic and renal dysfunctions (MELD score  ≤ or >15 and KDOQI stages, respectively). In the whole population, CystC-based equations showed a better performance than Pcr-based ones (lower bias and higher 10% and 30% accuracies). CKD-EPI-CystC equation showed the best performance whatever the ascites severity and in presence of a significant renal dysfunction (GFR <60 mL/min/1.73 m(2)).
  
  
  CONCLUSIONS
  Pcr-based GFR predicting equations are not reliable in pre-OLT patients even when an IDMS-traceable enzymatic Pcr assay is used. Whenever a CystC-assay traceable to primary reference materials is performed and when a true measurement of GFR is not possible, CystC-based equations, especially CKD-EPI-CystC, may be recommended to evaluate renal function and for KDOQI staging.
authors.affiliation: Exploration Fonctionnelle Rénale et Métabolique, Groupement Hospitalier Edouard Herriot, Hospices Civils de Lyon, France; Post-Graduate Program in Medical Sciences, FAMED-Programa de Pós Graduação em Saúde da Criança e do Adolescente-Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Universidade de Caxias do Sul, Centro de Ciências da Saúde, School of Medicine, Brazil.
authors.forename: Vandréa
authors.initials: V
authors.lastname: De Souza
authors.forename: Aoumeur
authors.initials: A
authors.lastname: Hadj-Aissa
authors.forename: Olga
authors.initials: O
authors.lastname: Dolomanova
authors.forename: Muriel
authors.initials: M
authors.lastname: Rabilloud
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rognant
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lemoine
authors.forename: Sylvie
authors.initials: S
authors.lastname: Radenne
authors.forename: Jérôme
authors.initials: J
authors.lastname: Dumortier
authors.forename: Colette
authors.initials: C
authors.lastname: Chapuis-Cellier
authors.forename: Françoise
authors.initials: F
authors.lastname: Beyerle
authors.forename: Chantal
authors.initials: C
authors.lastname: Bon
authors.forename: Jean
authors.initials: J
authors.lastname: Iwaz
authors.forename: Luciano
authors.initials: L
authors.lastname: Selistre
authors.forename: Laurence
authors.initials: L
authors.lastname: Dubourg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007444:Inulin / Q000378:metabolism; D007668:Kidney / Q000502:physiology*; D008103:Liver Cirrhosis / Q000097:blood / Q000601:surgery*; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D007444:Inulin; D003404:Creatinine