Reclassification of chronic kidney disease patients for end-stagerenal disease risk by proteinuria indexed to estimated glomerular filtration rate: multicentre prospective study in nephrology clinics

Background.In non-dialysis chronic kidney disease (CKD), ab-solute proteinuria (Uprot) depends on the extent of kidneydamage and residual glomerular filtration rate (GFR). Wetherefore evaluated, as compared with Uprot, the strength of as-sociation of proteinuria indexed to estimated GFR (eGFR) withend-stage renal disease (ESRD) risk.Methods.In a multi-cohort prospective study in 3957 CKDpatients of Stages G3–G5 referred to nephrology clinics, wetested two multivariable Cox models for ESRD risk, with either Uprot (g/24 h) or filtration-adjusted proteinuria (F-Uprot) cal-culated as Uprot/eGFR100.Results.Mean6SD age was 67614 years, males 60%, dia-betics 29%, cardiovascular disease (CVD) 34%, eGFR32613 mL/min/1.73 m2, median (interquartile range) Uprot0.41 (0.12–1.29) g/24 h and F-Uprot 1.41 (0.36–4.93) g/24 h per100 mL/min/1.73 m2eGFR. Over a median follow-up of44 months, 862 patients reached ESRD. At competing riskanalysis, ESRD risk progressively increased when F-Uprot was1.0–4.9 and5.0 versus<1.0 g/24 h per 100 mL/min/1.73 m2eGFR in Stages G3a–G4 (P