Controlled, prospective trial of steroid treatment in IgA nephropathy: A limitation of low-dose prednisolone therapy

Background: No accepted therapy has been established for progressive immunoglobulin A (IgA) nephropathy. Methods: A prospective, randomized, controlled trial of low-dose prednisolone therapy was performed in patients with IgA nephropathy with moderate histological characteristics. Forty-three patients in the steroid group and 47 patients in the control group were included in the study. The initial dose of prednisolone was 20 mg/d, gradually tapered to 5 mg/d during 2 years. Results: Baseline urine protein-creatinine ratio (UP-UCR) was significantly greater in the steroid group than in controls. Follow-up duration was 65 ± 25 months in the steroid group and 64 ± 23 months in controls. Changes in UP-UCR from baseline, ie, UP-UCR at last follow-up minus UP-UCR at baseline, were significantly lower in the steroid group than in controls (steroid group, -0.84 ± 1.78; controls, 0.26 ± 1.65; P = 0.0034). Kidney survival was similar in both groups. Patients were divided into two subgroups according to clinical course. There were 28 improved patients and 15 unimproved patients in the steroid group and 27 improved patients and 20 unimproved patients in the control group. In the steroid group, UP-UCR was significantly greater in the unimproved than improved subgroup (3.1 ± 2.6 versus 1.8 ± 1.5). Conclusion: These data suggest that our protocol had an antiproteinuric effect, but could not improve kidney survival. Because the effect of steroid therapy to prevent the progression of IgA nephropathy is believed to be linked closely to reduction in urinary potein, an insufficient dose of prednisolone in our protocol may be the reason for the discrepancy between the effect on proteinuria and kidney survival.