Abstract:

Objectives: To iinvestigate the long-term renal survival rate and related risk factors of progression to renal failure in Chinese adult patients with IgA nephropathy (IgAN) and to quantify the effects of proteinuria during the follow-up on outcome in patients with IgAN. Methodology: The patients with biopsy-proven primary IgAN in the Nanjing Glomerulonephritis Registry were studied. Renal survival and the relationships between clinical parameters and renal outcomes were assessed. Results: 1126 patients were enrolled in this study. The 10, 15, and 20-year cumulative renal survival rates, calculated by Kaplan-Meier method, were 85%, 76% and 67% respectively. At the time of biopsy, proteinuria>1.0g/d (HR 3.3，P<0.001), eGFR<60 ml/min per 1.73m2 (HR 2.2，P<0.001), hypertension (HR 2.0，P<0.001), and hyperuricemia (HR 1.8，P=0.002) were the independent risk factors. Multivariate COX analysis showed the time-average proteinuria (TA-P) during follow-up was the most important risk factor of renal failure. The patients with TA-P>1.0g/d were associated with a 9.8-fold risk than that patients with TA-P<1.0g/d (P<0.001), and 67.7-fold risk than those with TA-P<0.5g/d (P<0.001). The patients with TA-P<0.5g/d were better than those with TA-P between 0.5 and 1.0g/d (HR 13.1, P<0.001). Conclusions: 33% of Chinese adult patients with primary IgAN have progressed to End Stage Renal Disease (ESRD) within 20 years. Four clinical features--higher proteinuria, hypertension, impaired renal function, and hyperuricemia are independent predictors of an unfavorable renal outcome. The basic goal of antiproteinuric therapy for Chinese patients is to lower proteinuria to <1.0g/d, and the optimal goal is to lower proteinuria to <0.5g/d.