Outcomes Associated With Microalbuminuria: Effect Modificatin By Chronic Kidney Disease.

Abstract

OBJECTIVES: To compare association of microalbuminuria with outcomes in patients with different comorbidities. BACKGROUND: The risk of adverse outcomes associated with proteinuria has been found to be linearly decreasing with even low-normal levels of microalbuminuria. It is unclear if comorbid conditions change these associations. METHODS: We examined the association of urine microalbumin-creatinine ratio (UACR) with mortality and the slopes of estimated glomerular filtration rate (eGFR) in a nationally representative cohort of 298,875 US veterans. Associations of UACR with all-cause mortality overall and in subgroups of patients with and without diabetes, hypertension, cardiovascular disease, congestive heart failure and advanced CKD were examined in Cox models, and with the slopes of eGFR in linear and logistic regression models. RESULTS: Very low levels of UACR were linearly associated with decreased mortality and less progression of CKD overall: adjusted mortality hazard ratio and estimated glomerular filtration rate slope (95%CI) associated with UACR =200, compared to <5 mcg/mg were 1.53 (1.38-1.69, p<0.001) and -1.59 (-1.83, -1.35, p<0.001). Similar linearity was present in all examined subgroups, except in patients with CKD in whom a U-shaped association was present and in whom a UACR of 10-19 was associated with the best outcomes. CONCLUSIONS: The association of UACR with mortality and with progressive CKD is modified in patients with CKD, who experience higher mortality and worse progression of CKD with the lowest levels of UACR. Proteinuria-lowering interventions in patients with advanced CKD should be implemented cautiously, considering the potential for adverse outcomes.