Concordancia en pacientes críticos entre las ecuaciones diseñadas para la estimación del filtrado glomerular y el aclaramiento de creatinina en orina de 24 h

Abstract

Objective To study the behavior of the different equations used to estimate glomerular filtration rate (GFR) applied to critical care patients compared to the standard method: 24-hour creatinine clearance (24-CrCl). Design Retrospective analysis of data base from a previous observational prospective study. Setting Polyvalent ICU in a tertiary Hospital. Population All adult patients admitted to our Unit during the study who had a bladder catheter inserted. Anuric patients were excluded. Interventions We measured 24-CrCl and estimated GFR by MDRD, modified Jelliffe (JF), Mayo-Clinic (CM) and Cockroft-Gault (C-G) equations. Variables To evaluate degree of agreement, we grouped patients regarding 24-CrCl as normal (>70), moderate dysfunction (69–50) or severe renal dysfunction (< 50 mL/min/1.73 m 2). Results 307 patients, aged 54±18, 69.7% males. Measured 24-CrCl was 109.2±78.2 mL/min/1.73 m 2 and the estimate one 95.5±56.7 for JF, 87.4±53.4 for C-G, 86.9±55.9 for MDRD and 85.6±39.9 for CM. The difference was significant (p<0.001) for all estimates but lower for (13.7±53.2 mL/min/1.73 m 2) than C-G (21.9±58.3), CM (23.6±59.6) or MDRD (22.3±60.4). Correlation coefficient was 0.73 for JF, 0.67 C-G or CM and 0.64 for MDRD. The degree of agreement was only fair for all measures (Kappa 0.55 for JF or MDRD, 0.51 for C-G and 0.5 for CM). Conclusions Modified Jelliffe equation showed higher agreement with 24-CrCl than Cockroft-Gault, MDRD or Mayo-Clinic equations when used in critically ill patients. However, when exact measurement is needed, none of the equations can be considered adequate and in these cases, the CrCl should be calculated.