Clinical Profile and Outcome of C3-dominant Glomerulonephritis: Retrospective study

ABSTRACT: Background: Complement 3(C3)-dominant Glomerulonephritis (GN) are rare diseases resulting from alternative complement pathway dysregulation, include C3 Glomerulopathy(C3G), paraprotein associated GN and C3 dominant infection-related glomerulonephritis (IRGN). To our knowledge long-term follow-up studies of clinical profile and outcomes of this rare disorder are sparse. We studied kidney histopathology baseline findings, outcomes, treatment, and its complications of C3-dominant GN in our setting. Objectives: We studied the clinical, pathological profiles and outcomes of patients with C3-dominant GN. Methods: Design: Single centre, retrospective, case record based observational study. Participants: Consecutive patients of C3-dominant GN on kidney biopsy from 2013 to 2023. Measurements: Demography, laboratory and histopathological data, treatment and outcomes were studied. Results: Of 2175 kidney biopsies, 141(6.48%) showed C3-dominant Glomerulonephritis; 74 (52.5%) C3G, 67(47.5%) IRGN. Median age was 43 years (IQR 29-59.5), males 90 (63.8%). Preceding skin/throat infections were seen in 32/141 (22.7%). At presentation median serum creatinine was 1.7mg/dL (IQR: 1.2-3.6), eGFR <60ml/min/1.73m2 in 91/141 (64.5%), 111/141 (78.7%) had low serum C3 levels. Nephrotic proteinuria was seen in 65/141 (46%), Crescents in 45(31.9%). Remission was partial in 38/141(27%), complete in 45/141(31.9%) and 31/141(22%) progressed to End stage kidney disease (ESKD). On immunosuppression commonest infection was pneumonia in 15/70 (21.4%) and 27/141(19.1%) died at an average follow up of 25.7 months. Diabetes mellitus, percentage sclerosis and presence of crescents predicted development of CKD stage 5. Conclusion: Over ten years, C3-dominant GN represented 6.48% of kidney biopsies. Nephrotic proteinuria and kidney failure are common at presentation with 58% achieving some remission, 22 % going on to ESKD and mortality of 19%.