Abstract
BACKGROUND: Respiratory syncytial virus (RSV) is a common respiratory viral illness which can cause severe outcomes in older and immunosuppressed populations. There is little data regarding RSV outcomes among people with systemic autoimmune rheumatic diseases (SARDs). METHODS: This retrospective cohort study examined risk factors for hospitalization in individuals with SARDs and documented RSV infection between 2015 and 2023 at Mass General Brigham (Boston, MA). Clinical data were collected from electronic health records. Multivariable adjusted logistic regression was used to identify factors associated with hospitalization for RSV infection. RESULTS: Of 188 individuals with SARDs and RSV (mean age 68.5 years, 75.5% female), 96 (51.0%) were hospitalized. Higher Charlson Comorbidity Index (aOR 1.16 per point, 95% CI: 1.04-1.31), Claims-Based Frailty Index (aOR 4.80 vs. robust/pre-frail, 95% CI: 2.32-9.94), and concurrent infection (aOR 2.52 vs. RSV alone, 95% CI: 1.07-5.92) were associated with increased odds of hospitalization. CD20 inhibitor treatment (aOR 3.84 vs. csDMARD, 95% CI: 0.99-15.20) and older age (OR 1.03 per year, 95% CI: 1.01-1.05) were associated with numerically increased odds of RSV hospitalization. Among hospitalized individuals, 56% required oxygen. There were 12 deaths within 90 days (12.5% of those hospitalized; 6% of all with RSV). CONCLUSIONS: This study highlights the increased risk of severe outcomes of RSV infection in individuals with SARDs. Factors associated with RSV hospitalization included frailty, higher comorbidity burden, and concurrent infection at the time of RSV. These findings should inform clinical decisions regarding RSV vaccination and prevention strategies.