Abstract
OBJECTIVE: Treatment regimens combining glucocorticoids with cyclophosphamide or rituximab or both are used to induce remission in ANCA-associated glomerulonephritis (ANCA-GN). There is a paucity of data on the efficacy and safety of these regimens in elderly patients with ANCA-GN. This study aimed to examine outcomes and adverse events in elderly AAV patients with three induction regimens: cyclophosphamide (CYC), cyclophosphamide and rituximab (CYC + RTX), and rituximab (RTX). METHODS: This single-center retrospective cohort study included patients 60 years and older diagnosed with ANCA-GN. Baseline characteristics and outcomes across several clinical parameters were recorded and compared for significance using Kruskal-Wallis test, Chi-squared test, Fisher exact test, univariate, and multivariate logistic regression as appropriate. Cox proportional hazard regression model was used for survival analysis. RESULTS: Seventy-five patients were included. The mean (SD) age at diagnosis was 70 (± 6) years. The mean (SD) follow-up duration was 5.17 (± 3.47) years. Remission induction therapy with glucocorticoids plus CYC was used in 25 patients, glucocorticoids plus CYC and RTX in 12 patients, and glucocorticoids plus RTX in 38 patients. RTX-treated patients had a higher baseline estimated glomerular filtration ratio (eGFR) (p = 0.00009). High remission rates were achieved in all groups (100% vs. 100% vs. 94.6% respectively, p = 0.368). The incidence of end-stage renal disease (ESRD) at one year was 8% among all groups (p = 0.999). There was no difference in the number of infections requiring hospitalization (p = 0.822), but a statistical difference in leukopenia was noted (32% vs. 25% vs. 3% respectively, p = 0.005). The use of RTX only was associated with reduced leukopenia (aOR = 0.1, 95% CI = 0.005-0.8) after adjusting for other variables. CONCLUSIONS: CYC, CYC + RTX, and RTX are equally effective for remission induction in elderly patients with ANCA-GN. Induction therapy with RTX only was associated with a lower risk of leukopenia compared to CYC-containing regimens. Infections requiring hospitalization were similar among all groups. End-stage kidney disease at one year was comparable among the 3 groups. Key Points • Cyclophosphamide, Rituximab, and Cyclophosphamide+Rituximab are equally effective in remission induction in elderly patients with ANCA glomerulonephritis. • The use of Rituximab only was associated with a lower risk of bone marrow suppression compared to Cyclophosphamide only. • More information is needed on the comparative safety of induction therapy strategies in elderly ANCA glomerulonephritis patients.