Objective: In the current study, we evaluated the efficacy of methylprednisolone (MP) pulse therapy in IgA nephropathy (IgAN) patients with established renal function impairment.
Patients and methods: We retrospectively analyzed the effect of MP pulse therapy in patients with histologically active IgAN (8 males, 12 females) whose estimated glomerular filtration rate was less than 60 mL/min/1.73 m2 (33.4 +/- 13.1, mean +/- SD). The efficacy of the MP pulse therapy was analyzed by calculating the regression coefficients (dL/mg/month) from the slopes of the 1/serum creatinine (Cr), urine protein/creatinine ratio (g/g x Cr), and the estimated interval from the pulse therapy to dialysis (that is, for Cr to reach 8 mg/dL, as calculated from the slope of 1/Cr) or the actual interval.
Results: All patients showed improved regression coefficients (-0.0214 +/- 0.00166 vs. 0.00236 +/- 0.00895, 1 year before vs. after treatment, p < 0.01). The severity of proteinuria decreased significantly from a mean urine protein/creatinine ratio of 2.9 +/- 1.7 before therapy to 1.1 +/- 0.8 (p < 0.01) at 6 months and 0.8 +/- 0.7(p < 0.01) at 12 months after therapy. Although 7 patients underwent dialysis, the average interval from pulse therapy to dialysis was prolonged from an estimated interval of 1.1 +/- 0.9 years to an actual interval of 4.1 +/- 3.5 years. Six patients showed positive regression coefficients at the last observation (4.1 +/- 3.0 years after therapy). The remaining 7 patients who had not undergone dialysis also showed prolongation of the estimated interval from pulse therapy to dialysis of 5.9 +/- 5.1 years before pulse therapy to 25.7 +/- 20.6 years at the final observation (4.9 +/- 3.5 years after therapy). No serious side effects were observed in any of the patients.
Conclusion: MP pulse therapy can slow the progression of renal deterioration in patients with active IgAN, even in those patients in whom renal function impairment has set in.