Corticosteroids or immunosuppressants were not superior to supportive care in IgA nephropathy patients with mild proteinuria.

Background: We aimed to evaluate the effect of immunosuppressant therapy for immunoglobulin A nephropathy (IgAN) patients with mild proteinuria (<1 g/d).

Methods: We recruited patients with biopsy-proven IgAN from 4 study centers. Patients were followed for more than 1 year or up to the study end point. Clinical indexes, renal pathological data, and treatment information were collected during the follow-up period. IgAN patients with mild proteinuria (<1 g/d at biopsy) were included. Patients were divided into a supportive care group (SC) and an immunosuppressant group (IT). Patients in the SC group received the optimal dose of renin angiotensin system inhibitors (RASi). Patients in the IT group received corticosteroids or immunosuppressant therapy plus RASi. Responses to therapy included complete remission (CR), partial remission (PR), no response (NR), and end stage renal disease (ESRD). A 50% decline in estimated glomerular filtration rate (eGFR) and/or ESRD was the primary end point of this study.

Results: 295 patients (36.3% male and 63.7% female) were included in this study and were followed for 49.46 ± 24.35 months. We found a significant difference in estimated glomerular filtration rate, urine protein, mesangial hypercellularity, segmental glomerulosclerosis, cellular or fibrocellular crescents, and glomerulosclerosis between the 2 treatment groups at baseline. At the final follow-up, 224 patients (75.9%) achieved CR, 7 patients (2.4%) achieved PR, 55 patients (18.6%) had NR, and 9 patients (3.1%) reached ESRD. However, no significant differences were observed between the SC and IT groups with respect to CR (76.4% vs 73.5%, P = .659), PR (2.0% vs 4.1%, P = .329), NR (18.3% vs 20.4%, P = .728), and ESRD (3.3% vs 2.0%, P = 1.000). Kidney survival rates were also comparable between the SC and IT groups (93.7% vs 94.1%, P = .808). We observed similar results after subgroup analysis according to chronic kidney disease stages or pathological manifestations. A multivariate model showed that segmental sclerosis (HR 9.55, 95% CI 1.04-88.16, P = .047) and glomerulosclerosis (HR 21.09, 95% CI 1.39-320.53, P = .028) were independent predictors of poor renal survival.

Conclusions: Corticosteroids or immunosuppressants were not superior to supportive care in IgA nephropathy patients with mild proteinuria.