Trimethoprim-sulfamethoxazole prophylaxis during treatment of granulomatosis with polyangiitis with rituximab in the United States of America: a retrospective cohort study

Background Antibiotic prophylaxis is recommended during ANCA-associated vasculitis (AAV) induction. We aimed to describe the frequency, persistence, and factors associated with trimethoprim-sulfamethoxazole (TMP-SMX) use in an adult population sample with granulomatosis with polyangiitis (GPA) treated with rituximab (RTX). Methods We identified adults with GPA treated with RTX within the Merative (TM) Marketscan (R) Research Databases (2011-2020). TMP-SMX prophylaxis was defined as a >= 28-day prescription dispensed within a month of starting RTX. We estimated TMP-SMX persistence, allowing prescription refill gaps of 30 days. Multivariable logistic regression and Cox proportional hazards regression assessed the factors associated with baseline TMP-SMX use and persistence, respectively. Covariates included age, sex, calendar year, insurance type, immunosuppressant use, hospitalization, and co-morbidities. Results Among 1877 RTX-treated GPA patients, the mean age was 50.9, and 54% were female. A minority (n = 426, 23%) received TMP-SMX with a median persistence of 141 (IQR 83-248) days. In multivariable analyses, prophylaxis was associated with prednisone use in the month prior to RTX (>= 20 mg/day vs none, OR 3.96; 95% CI 3.0-5.2; 1-19 mg/day vs none, OR 2.63; 95% CI 1.8-3.8), and methotrexate use (OR 1.48, 95% CI 1.04-2.1), intensive care (OR 1.95; 95% CI 1.4-2.7), and non-intensive care hospitalization (OR 1.56; 95% CI 1.2-2.1) in the 6 months prior to RTX. Female sex (OR 0.63; 95% CI 0.5-0.8) was negatively associated with TMP-SMX use. Conclusions TMP-SMX was dispensed to a minority of RTX-treated GPA patients, more often to those on glucocorticoids and with recent hospitalization. Further research is needed to determine the optimal use and duration of TMP-SMX prophylaxis following RTX in AAV.