Role of immunosuppressive therapy and predictors of therapeutic effectiveness and renal outcome in IgA nephropathy with proteinuria

INTRODUCTION The aim of the study was to analyze the role of immunosuppressive therapy and identify independent predictors of therapeutic effectiveness and outcome in IgA nephropathy (IgAN) patients with proteinuria. MATERIAL AND METHODS Two hundred and six IgAN patients with proteinuria (1-3.5 g/day) were included between January 2005 and December 2011, and divided into two groups: group A (n = 125), receiving renin-angiotensin system blockade therapy alone; and group B (n = 81), combining the above with immunosuppressive therapy. The clinicopathological features, response and safety were recorded. In univariate and multivariate models, the factors that influence response to therapy and renal outcome, especially pathologic features, were analyzed. RESULTS The patients in group B presented more severe proteinuria and hypoalbuminemia with more severe hematuria (p < 0.05) but no significant difference in the pathologic changes compared with group A. After follow-up, the response rate was higher in group B than in group A (p < 0.001). No pathologic feature or clinical parameter apart from steroid therapy (HR = 0.500, 95% CI: 0.304-0.821, p = 0.006) was strongly associated with therapeutic effectiveness. Endocapillary hypercellularity (HR = 2.849, 95% CI: 1.244-6.524, p = 0.013) seemed to be an independent predictor of poor response to steroid therapy. The renal survival rate was not significantly different between the two groups (p = 0.074). Estimated glomerular filtration rate at baseline may be an independent predictor of renal outcome. CONCLUSIONS Steroid therapy could be an effective therapy in proteinuric IgAN patients, and endocapillary hypercellularity seemed to predict poor response to steroid. Renal function at baseline rather than treatment strategies and pathologic features may be independently associated with renal survival.