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™ Marketscan® Research Databases (2011–2020). TMP-SMX prophylaxis was defined as a [Formula: see text] 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 ([Formula: see text] 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. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13075-023-03114-7.