High Albumin Clearance Predicts the Minimal Change Nephrotic Syndrome Relapse.

Abstract

Although albuminuria leakage that occurs in minimal change nephrotic syndrome (MCNS) may be related to the disease state, albumin kinetics in MCNS has never been evaluated. In this study, we investigated albumin kinetics in adult Japanese patients with MCNS by the estimated 24-h albumin clearance (eCALB) and examined the association between eCALB and relapse. We retrospectively identified 103 adult patients with a histological diagnosis of MCNS from four hospitals in Japan (2010-2020). The primary outcome is the first relapse in 2 years after complete remission (CR) following corticosteroid therapy. The estimated 24-h albumin clearance (eCALB) [µL/min] was defined as (2.71828log(0.0445 + 0.9488*log(urinary protein) [g/24h]/(serum albumin [g/dL] × 1440 [min/24 h]) for women and (2.71828log(-0.1522 + 0.9742*log(urinary protein) [g/24h]/(serum albumin [g/dL] × 1440 [min/24 h]) for men. Relapse was observed in 44 patients (103 kidney biopsy samples; 42.7%). The mean patient age was 41.0 years. Patients had an estimated glomerular filtration rate (eGFR) of 71.0 mL/min/1.73 m2, urinary protein excretion (UPE) of 6.8 g/day, serum albumin of 1.4 g/dL, and eCALB of 2.27 μL/min. eCALB was strongly associated with hypoalbuminemia, severe proteinuria, lipid abnormalities, and coagulopathy. In the multivariable analysis, a high eCALB was significantly associated with relapse after adjusting for age, eGFR, time to CR, and UPE (adjusted hazard ratio = 5.027, 95% confidence interval 1.88-13.47, P = 0.001). This study revealed that eCALB, which could substitute albumin kinetics, reflected the severity of MCNS, and a high eCALB was associated with recurrence.