Effect of proteinuria on the rapid kidney function decline in chronic kidney disease depends on the underlying disease: A post hoc analysis of the BRIGHTEN study

Abstract

AimsIt is unclear whether the effect of proteinuria on rapid kidney function decline is equivalent among diabetic kidney disease (DKD), non-DKD with diabetes (NDKD+DM), and nephrosclerosis without diabetes (NS-DM), particularly in advanced chronic kidney disease patients. MethodsIn total, 1038 chronic kidney disease patients who participated in the BRIGHTEN study were included in the present study. A linear mixed effect model was applied to estimate the annual estimated glomerular filtration rate decline in each disease group. ResultsThe prevalence of rapid decliners (rapid kidney function decline, defined as an eGFR loss of > 5 mL/min/1.73 m2/year) in the DKD group (44.6 %) was significantly higher compared with the NDKD+DM (27.9 %) and NS-DM (27.0 %) groups. By contrast, the prevalence of rapid decliners in different urine total protein to creatinine ratio (UPCR) categories (<0.5, 0.5 to < 1.0, 1.0 to < 3.5, and ≥ 3.5 g/g) were equivalent between the DKD and NS-DM groups. Moreover, the prevalence of a UPCR < 1.0 g/g in rapid decliners of the NS-DM group was more than double than in those of the DKD and NDKD+DM groups. ConclusionsThe risk of rapid kidney function decline in NS-DM patients with low levels of proteinuria may be greater than initially predicted.