Long-term outcome of secondary steroid-resistant nephrotic syndrome in Chinese children

Introduction Secondary steroid-resistant nephrotic syndrome (SRNS) refers to the condition when patients with initial steroid-sensitive nephrotic syndrome develop steroid resistance in subsequent relapses. Long-term outcomes of secondary SRNS in children are uncertain. Methods This was a single-center retrospective study of 56 children with secondary SRNS between 2006 and 2016. The survival curve was estimated using the Kaplan-Meier method. Independent risk factors for end-stage renal disease (ESRD) were determined using Cox proportional hazards model. Results The median time from nephrotic syndrome onset to secondary SRNS was 7.8 months. Biopsy results at diagnosis secondary SRNS showed that 64.3% of cases were minimal change disease (MCD). No remission was observed in seven (12.5%) patients within the first year. The mean follow-up time was 7.8 ± 3.2 years. Eight patients were clinically cured, one died before ESRD, 10 reached ESRD, and 75.0% (3 of 4) of patients recurred post-transplantation. The 10-year ESRD-free survival rate was 85.8%. No response to intensified immunosuppression (IIS) in the first year was the independent predictor for ESRD. Repeat biopsies were performed in 20 cases, revealing that the reclassification from MCD to mesangial hypercellularity and focal segmental glomerulosclerosis (FSGS) in two when secondary steroid resistance appeared, from MCD and mesangial hypercellularity to FSGS in seven who developed multidrug resistance, and from FSGS to MCD and mesangial hypercellularity in two with favorable outcomes. Conclusions The long-term outcome in children with secondary SRNS was heterogeneous, and no response to IIS in the first year was the independent predictor for ESRD. In patients with repeat biopsy, changes in histological appearance to FSGS were associated with multidrug resistance.