Long-term evaluation of the timing of corticosteroid therapy in an IgA nephropathy cohort

ABSTRACT Background Current proposed KDIGO guidelines suggest systemic corticosteroid therapy to reduce glomerular inflammation in immunoglobulin A nephropathy (IgAN), however the optimal timing for initiating steroid treatment remains a topic of debate. This study evaluates the impact of early versus delayed steroid initiation on long-term outcomes in IgAN patients. Methods We conducted a retrospective study of 268 IgAN patients treated with corticosteroids for >3 months within 3 years of kidney biopsy. Patients were categorized into early therapy (steroids within 30 days) and delayed therapy (after 30 days). Propensity score matching created matched cohorts. Kaplan–Meier curves and Cox regression assessed outcomes. The primary endpoint was a composite renal outcome [estimated glomerular filtration rate (eGFR) >50% reduction, end-stage kidney disease or renal death]. Secondary endpoints included eGFR decline >30% or >40% and an eGFR slope and time-average proteinuria. Results Propensity score matching identified 191 individuals for analysis. The primary outcome was significantly better in the early therapy group, with a hazard ratio (HR) of 0.41 [95% confidence interval (CI) 0.17–0.96, P = .041]. Significant benefits were also observed for secondary outcomes, including a lower frequency of >30% and >40% eGFR decline in the early therapy group, with HRs of 0.48 (95% CI 0.24–0.98, P = .04) and 0.34 (95% CI 0.14–0.81, P = .01), respectively. Cox regression confirmed that the timing of steroid initiation (early vs delayed) was a significant factor associated with kidney progression [HR = 0.33 (95% CI 0.14–0.77), P = .01]. The average eGFR slope over 10 years was more favorable in the early therapy group (–1.0 ± 6.0 vs –2.9 ± 6.8 mL/min/1.73 m2 per year, P = .039). No significant differences in baseline characteristics were found to influence the timing of steroid use in progressive IgAN. Conclusions Early corticosteroid therapy may help reduce renal decline and preserve long-term kidney function in IgAN patients requiring steroid treatment.