Idiopathic membranous nephropathy with focal segmental sclerosis

Aim. To evaluate the clinical and pathological features and prognosis of idiopathic membranous nephropathy (IMN) with focal segmental sclerosis (FSGS) in a group of Russian patients. Materials and methods. 101 patients with morphologically verified IMN were enrolled in our single-center cohort retrospective study. The patients were divided into IMN group and IMN+FSGS group. The primary and secondary outcomes were analyzed in 59 patients, which had follow-up data for period more than 6 months. Results. At the time of renal biopsy the median age was 46.0 (33.0; 55.0) years and the median follow-up was 6.8 (4.0; 15.6) months. Secondary FSGS was revealed in 15 (14.9%) patients with IMN. The IMN and IMN+FSGS groups did not differ in gender, age of onset IMN and age of renal biopsy. In the IMN+FSGS group proteinuria was higher and estimated glomerular filtration rate was lower than that in the IMN group (p0.05). The systolic arterial pressure and creatinine levels in the IMN+FSGS group were slightly higher than in the IMN group, but the difference was not significant. Anti-PLA2R positivity was similar in both groups. Chronic kidney disease (CKD) progression was observed in 10/52 (19.2%) and 5/7 (71.4%) patients in IMN and IMN+FSGS groups, respectively. In a multivariate Cox regression model, age of renal biopsy (odds ratio – OR 1.12, 95% confidence interval – CI 1.03–1.22; р=0.07), FSGS (OR 0.05, 95% CI 0.01–0.34; р=0.002) и response to initial course of immunosuppression (OR 0.33, 95% CI 0.12–0.95; р=0.039) were associated with the CKD progression. Conclusion. In patients with IMN secondary FSGS is associated with a greater severity of proteinuria and a decrease in estimated glomerular filtration rate, and is also an independent factor of the CKD progression.