The association of 5-year therapeutic responsiveness with long-term renal outcome in IgA nephropathy.

Abstract

Immunoglobulin A nephropathy (IgAN) is the most common type of primary glomerulonephritis. Since most patients have a relatively benign renal prognosis, long-term follow-up is required. During such a long course of disease, relapse of IgAN is occasionally observed after upper respiratory tract infection or without any trigger. However, little is known about the impact of relapse on long-term renal outcomes. In this retrospective cohort study of biopsy-proven primary IgAN, we analyzed the association of 5-year therapeutic responsiveness (relapse) with the subsequent development of end-stage kidney disease (ESKD) using a 5-year landmark analysis (Cox model) and explored predictors of relapse from histological and clinical data at baseline. Among 563 patients from the exploratory cohort, most relapses (13.7%) occurred within 5years after treatment. Using 5-year landmark analysis, among 470 patients, 79 developed ESKD during a median follow-up period of 155months. Even after adjustment for clinicopathological relevant confounders, hazard ratios (95% confidence intervals) in the relapse and non-responder groups compared with the remission group were 2.86 (1.41-5.79) and 2.74 (1.48-5.11), respectively. Among 250 patients who achieved remission within 5years, proteinuria, eGFR, mesangial hypercellularity, endocapillary hypercellularity, segmental sclerosis, and crescent, but not interstitial fibrosis/tubular atrophy, were independent predictors of 5-year relapse in multivariable logistic regression analysis, CONCLUSIONS: Both relapsers and non-responders had similarly strong association with ESKD in patients with IgAN. We also confirmed the predictors of relapse 5years after renal biopsy, which may guide the treatment strategies for patients with IgAN who occasionally relapse after remission.