Long-term outcomes of IgA nephropathy patients with less than 25% crescents and mild proteinuria

Background: Whether immunosuppressive therapy in IgA nephropathy (IgAN) patients with less than 25% crescents (C1) and mild proteinuria can improve the renal outcome is still unclear.

Methods: We recruited 140 IgAN patients with C1 and proteinuria < 1 g/24 h who received supportive care (n = 52) or steroid-based immunosuppressive therapy (n = 88) in Xijing Hospital from July 2008 to December 2016. The primary outcome was the rate of renal function decline.

Results: The median of proteinuria was 575.5 mg/24 h, the fraction of crescents was 7% (5%, 12%) and follow-up time was 69.1 months. The rate of renal function decline [0.5 (- 1.5, 3.2) vs - 0.7 (- 3.5, 0.5) ml/min per 1.73 m² per year; P = 0.01] was slower in steroid-based immunosuppressive therapy group than supportive care group. Multivariate linear regression analyses showed steroid-based immunosuppressive therapy significantly slowed down the rate of renal function decline (β = - 0.220, 95% CI - 3.804 to - 0.449, P = 0.013) after adjusting age, sex, MAP, proteinuria, eGFR, M1, E1, S1, T1-2, the fraction of crescents and RASB. In the matched cohort, the rate of renal function decline was also slower in steroid-based immunosuppressive therapy group. The incidence of adverse events was similar between the two groups.

Conclusion: Steroid-based immunosuppressive therapy may slow down the rate of renal function decline of IgAN patients with C1 and proteinuria ≤ 1 g/24 h.