In this retrospective cohort study, we aim to evaluate the effect of endocapillary hypercellularity (E) lesions on the renal prognosis and response to immunosuppressive therapy, especially diffuse endocapillary hypercellularity lesion in IgA nephropathy (IgAN). A total of 365 patients with IgAN and E lesions and 31 patients with diffuse E lesions and over 12-month follow-up period were included in this study. We performed an 1∶1 propensity score to identify controls with matched clinical and pathological features from 769 IgAN patients without E lesions. The end-point was defined as a 30% decrease in estimated glomerular filtration rate (eGFR) or end-stage kidney disease. The kidney survival of the two groups was compared by Kaplan-Meier analysis. During median follow-up period of 41 months, kidney survival rates in patients with E lesions were 96.0% at 1 year, 83.6% at 3 years, 67.7% at 5 years; while they were 96.9% at 1 year, 83.6% at 3 years, and 68.7% at 5 years in patients without E lesions (P=0.265).The HRof immunosuppressive therapy was 1.038 (95%CI 0.749-1.440) and 1.113 (95%CI 0.770-1.609) in patients not receiving immunosuppressive therapy (P=0.781). (2) During median follow-up period of 52.5 months, the kidney survival rates in patients with diffuse E-lesion were 100.0% at 1 year, 96.2% at 3 years, 74.5% at 5 years; while they were 96.2% at 1 year, 82.3% at 3 years, and 63.7% at 5 years in patients without E-lesion (P=0.158). The HR of immunosuppressive therapy was 0.625 (95%CI 0.213-1.839) and 0.447 (95%CI 0.028-7.191) in patients not receiving immunosuppressive therapy (P=0.825). E lesion or diffuse E lesion may not be associated with prognosis or response to immunosuppressive therapy.

Nephropathy,IgA; Endocapillary hypercellularity; Propensity analysis; Cohort studies