Urinary protein and renal prognosis in idiopathic membranous nephropathy: a multicenter retrospective cohort study in Japan

AbstractBackground: Several studies have revealed a relationship between proteinuria and renal prognosis in idiopathic membranous nephropathy (IMN). The benefit of achieving subnephrotic proteinuria (<3.5 g/day), however, has not been well described.Methods: This multicenter, retrospective cohort study included 171 patients with IMN from 10 nephrology centers in Japan. The relationship between urinary protein over time and a decrease of 30% in estimated glomerular filtration rate (eGFR) was assessed using time-dependent multivariate Cox regression models adjusted for clinically relevant factors.Results: During the observation period (median, 37 months; interquartile range, 16–71 months), 37 (21.6%) patients developed a 30% decline in eGFR, and 2 (1.2%) progressed to end-stage renal disease. Time-dependent multivariate Cox regression models revealed that lower proteinuria over time were significantly associated with a lower risk for a decrease of 30% in eGFR (primary outcome), adjusted for clinically relev...