Cohort study of advanced IgA nephropathy: efficacy and limitations of corticosteroids with tonsillectomy.

BACKGROUND: Elevated serum creatinine is associated with poor outcome in IgA nephropathy (IgAN). The efficacy and limitations of corticosteroids in advanced IgAN (Cr >or=1.5 mg/dl), however, remains controversial. METHODS: We retrospectively investigated 70 patients with advanced IgAN (Cr >or=1.5 mg/dl) classified into three groups according to their treatment regimens, that is, steroid pulse with tonsillectomy, conventional steroid, and supportive therapy. We evaluated the three groups to elucidate predictors for the endpoints ESRF and doubled serum creatinine from baseline. RESULTS: Steroid pulse with tonsillectomy, conventional steroid and supportive therapy were performed in 30, 25 and 15 patients, respectively. During the mean follow-up period of 70.3 (12-137) months, 41.4% of patients reached ESRF (13.3 vs. 56.0 vs. 73.3%, p < 0.001) and 45.7% doubled serum creatinine from baseline (16.7 vs. 64.0 vs. 73.3%, p < 0.001). The incidence of ESRF in the patients treated by steroid pulse with tonsillectomy was significantly lower than the incidences in the patients treated by conventional steroid and supportive therapy at a baseline creatinine level of 1.5-2 mg/dl, but no statistical difference was observed at a level of >2 mg/dl. The Kaplan-Meier estimated probability of renal survival without ESRF was 89.2, 74.1 and 72.2% at 5 years and 82.8, 51.0 and 45.1% at 8 years, respectively (p = 0.017). The predictors for ESRF, identified in a Cox proportional hazards model, were baseline serum creatinine (p < 0.001) and interstitial infiltrate (p = 0.003). Steroid pulse with tonsillectomy also had a protective effect on the risk of reaching ESRF (p = 0.013). By target cross-stratification, the patients with baseline creatinine of 1.5-2 mg/dl who underwent steroid pulse with tonsillectomy showed a better renal survival rate than the others (p < 0.001). CONCLUSION: Steroid pulse therapy combined with tonsillectomy may be more effective than conventional steroid therapy in patients with a baseline creatinine level of <or=2 mg/dl.