Corticosteroids pulse therapy and oral corticosteroids therapy for IgA nephropathy patients with advanced chronic kidney disease: results of a multicenter, large-scale, long-term observational cohort study

BACKGROUND: Corticosteroids are widely used to reduce the urine protein levels of patients with immunoglobulin A nephropathy (IgAN). However, their potential preventive effects on end-stage kidney disease (ESKD) are unclear. METHODS: We previously performed a large-scale, long-term multicenter cohort study of patients with biopsy-proven IgAN treated between 1981 and 2013 (n = 1923). Based on the results, we reported that corticosteroids pulse therapy was potentially effective for the treatment of patients with an eGFR ≥30 ml/min/1.73m(2) and a urine protein amount of ≥1 g/gCr. In the present study, we extracted 766 patients with chronic kidney disease (CKD), stage G3–G4 (15 ≤ estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73m(2)) from the same cohort. We divided these patients into a steroid pulse (SP) group, oral steroid (OS) group, and no steroid (NS) group, and analyzed the risk of end-stage kidney disease (ESKD) stratified by eGFR and urine protein (UP) amounts. RESULTS: Over the median long-term follow-up of 70 ± 115 months, 37.1% of the patients with UP ≥1.0 g/day and 11.2% of the patients with UP < 1.0 g/day reached ESKD. Among the patients with UP ≥1 g/gCr, the SP group showed significantly better renal outcome (p < 0.001) than the OS and NS groups. In patients with UP < 1 g/gCr, there were no differences in renal survival among the treatment groups. These trends appeared even in the CKD stage G4 patients, and were also apparent in patients taking renin-angiotensin system inhibitors. The unprecedented long-term observation period in this study may have been necessary to reveal the favorable effect of corticosteroids on ESKD progression. CONCLUSIONS: In our long-term multicenter study, Corticosteroids pulse therapy was associated with better renal outcomes in IgAN patients with higher UP values, even if their eGFR values were low.