Predictors of response in patients with progressive IgA nephropathy treated with leflunomide and medium/low-dose corticosteroid

Objective To investigate the factors affecting the efficacy of leflunomide combined with medium/low dose corticosteroids in the treatment of progressive IgA nephropathy (IgAN). Methods Clinical and pathological parameters were collected retrospectively in patients of primary IgAN with proteinuria＞1.0 g/24 h and chronic kidney disease (CKD) stage 1-3 treated with leflunomide combined with medium/low dose corticosteroids in Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University from Jan 2005 to Dec 2010. According to the treatment effects, patients were divided into complete remission group and non-complete remission group. The biochemical and pathological indexes of the two groups were compared. Results A total of 42 patients were included. The remission rates at 3, 6, 9 and 12 months were 62%, 64%, 67% and 74%, respectively. Seventeen (40.5%) and fourteen (33.3%) patients achieved complete and partial remission after one-year treatment, and the remission rate remained stable within one year after withdrawal of drugs. The 24-hour proteinuria was 1.50 (0.67, 2.66) g, which was significantly reduced compared with the baseline 2.44 (1.36, 3.74) g (P＜0.01). The decrease rate was 31.3%. There was a slight decrease in proteinuria within one year after withdrawal of drugs. Estimated glomerular filtration rate (eGFR) remained stable during the treatment and a year of follow-up. No serious adverse event was observed during the follow-up period. Among 31 responder patients, 6(19.4%) patients relapsed. Logistic multivariate regression analysis suggested that the degree of renal interstitial inflammatory infiltration was an independent predictor of complete remission with one-year treatment of leflunomide combined with medium / low dose corticosteroids (HR=0.067, 95%CI 0.008-0.535, P=0.011). Conclusions IgAN treated with leflunomide and medium/low dose corticosteroids can achieve remission in early stage, and the remission rate remains stable after withdrawal of drugs. It is a safe option for the treatment of IgAN. Renal interstitial inflammatory infiltration is an independent predictor of complete remission.