Serum Albumin at Partial Remission Predicts Outcomes in Membranous Nephropathy

Abstract

Background: In primary membranous nephropathy (MN), partial remission (PR) (≥50% reduction of proteinuria to 12 months of follow-up. Characteristics at the time of PR associated with the composite outcome or relapse were evaluated using a time-to-event analysis. Results: A total of 192 patients attained PR and 86 attained CR. Serum albumin at PR (hazard ratio [HR]: 1.58 per 0.5 g/dl decrease from 4.0 g/dl; 95% confidence interval [CI]: 1.03–2.43) and duration of nephrotic proteinuria (HR: 1.01 per month increase; 95% CI: 1.00–1.03) were independent risk factors for the composite endpoint. Serum albumin at PR was associated with an increased risk of relapse (HR: 1.58 per 0.5 g/dl decrease below 4.0 g/dl; 95% CI: 1.24–2.01). A cutoff for serum albumin ≤3.5 g/dl at PR performed best in predicting relapse and composite outcome. Conclusions: Patients with serum albumin >3.5 g/dl at PR have decreased risk of composite outcome or relapse compared with PR with low albumin. A definition of PR that includes normalization of serum albumin may be a more robust surrogate endpoint in MN than the traditional definition of PR. Keywords: albuminemia, membranous nephropathy, nephrotic syndrome, proteinuria, remission, surrogate endpoint