Serum Albumin at Partial Remission Predicts Outcomes in Membranous Nephropathy.

BACKGROUND

In primary membranous nephropathy (MN), partial remission (PR) (≥50% reduction of proteinuria to <3.5 g/d) is associated with a greater risk of relapse and end-stage kidney disease (ESKD) compared with complete remission (CR). We aimed to determine factors associated with relapse or renal failure in patients who attain the standard definition of PR.

METHODS

We captured PR, CR, relapse, and the composite of doubling of serum creatinine or ESKD in a cohort of 267 patients with MN, nephrotic syndrome, and >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.