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.

[Display omitted] • GFR slope in DKD group was steeper than in non-DKD with diabetes (NDKD + DM) group. • GFR slope in DKD group was steeper than in nephrosclerosis (NS) group. • GFR slope was equivalent between NDKD + DM and NS groups. • Risk of rapid GFR decline in NS group was high even with low proteinuria (UPCR). • Upon UPCR matching, UPCR's impact on rapid GFR decline was similar in DKD and NS. It 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. In 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. The 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. The risk of rapid kidney function decline in NS-DM patients with low levels of proteinuria may be greater than initially predicted. [ABSTRACT FROM AUTHOR]