Real-World Analysis of Patients With C3 Glomerulopathy in the United States.

Introduction: C3 glomerulopathy (C3G) is a rare kidney disease caused by alternative pathway (AP) overactivation. This analysis describes demographic and clinical characteristics of patients with C3G in the United States (US) and evaluates chronic kidney disease (CKD) stage progression. Methods: This retrospective cohort study used electronic health records (EHRs) to identify patients aged ≥ 12 years with a C3G diagnosis (index) and with continuous clinical activity ≥ 12 months before (baseline) and ≥ 6 months after index (follow-up; until death or data end). Patients were stratified by prior kidney transplant status, CKD stage progression during follow-up, and baseline serum C3 level. CKD stage progression was assessed in patients with CKD stages 1 to 4 (at index) and adequate data to assess progression during follow-up. Results: Overall, 260 patients with C3G were identified: 51.9% were female; mean (SD) age was 47.8 (20.6) years; median follow-up was 2.1 years. Of those assessed, most had CKD stage ≥ 3 (56.6%) and proteinuria (54.4%) at index. Posttransplant recurrent C3G was reported in 27 patients (10.4%). Of those assessed for CKD stage progression, 102 (59.0%) and 45 (26.0%) progressed to a higher CKD stage or CKD stage 5 or kidney failure, respectively. Median time to progression of CKD stage or to stage 5 or kidney failure was 14.9 months and not estimable (NE), respectively. Conclusion: In a real-world US population of patients with C3G, we identified a population with both advanced kidney disease around the time of diagnosis and high rates of CKD stage progression, highlighting the need to utilize novel treatments to improve patient outcomes.