Early Association of Low-Grade Albuminuria and Allograft Dysfunction Predicts Renal Transplant Outcomes

Background. Data on the combined associations of albuminuria and estimated glomerular filtration rate (eGFR) with renal transplant outcomes are limited. Our objective was to explore how renal transplant outcomes could be predicted by a combined variable of early low-grade albuminuria and allograft dysfunction. Methods. We studied a cohort of adult deceased-donor kidney transplant recipients who were subdivided into four groups according to median albuminuria (100 mg/day, interquartile range, 0-470 mg/day) and median eGFR (60 mL/min/1.73 m(2); interquartile range, 30-73 mL/min/1.73 m2) at third month posttransplantation as follows: group I (albuminuria <100 and eGFR >60, n = 238); group II (albuminuria >= 100 and eGFR >60, n = 151); group III (albuminuria <100 and eGFR <= 60; n = 167); and group IV (albuminuria >= 100 and eGFR <= 60, n = 228). Results. Death-censored graft survival was significantly lower in group IV compared with the rest (P<0.0001). Multivariate Cox regression analysis using fixed and time-dependent covariates showed that the combination of low-grade albuminuria and lower eGFR was associated with graft failure (hazard ratio, 2.2, 95% confidence interval, 1.3-3.7; P=0.003). Likewise, but to a lesser extent, the risk of mortality was increased for group IV (hazard ratio, 1.7, 95% confidence interval, 1.01-2.8; P=0.042). Conclusions. Early association of low-grade albuminuria and allograft dysfunction represents an important risk factor of graft failure and mortality. This additive effect should be considered to identify individuals at risk for adverse kidney transplantation outcomes.