Statin use and medically attended acute respiratory illness among influenza vaccine recipients

Background: Previous studies have suggested that statins decrease influenza vaccine effectiveness and increase risk of medically attended acute respiratory illness (MAARI). Objectives: To examine the association of incident statin use and MAARI in a cohort of influenza vaccine recipients. Methods: This retrospective cohort study evaluated influenza vaccine recipients within the Tricare population. The primary outcome compared MAARI incidence during the follow-up period in a propensity score-matched cohort of incident statin users and statin non-users. Secondary analysis included propensity score-adjusted comparisons between incident statin users and statin non-users in the entire cohort and prespecified sub-cohorts with and without comorbidities. The propensity score was derived from 72 variables encompassing demographics, medical history, comorbidities, medication use, and healthcare utilization. Results: MAARI incidence in statin users was similar to non-users in the propensity score-matched cohort (odds ratio [OR] 0.92; 95% confidence interval [CI] 0.84–1.01). In contrast, statin users with lower comorbidity had lower OR for MAARI compared to non-users (Charlson Score zero cohort: 0.85 [CI 0.74–0.98]; No Diabetes cohort: 0.88 [CI 0.80–0.96]). Conclusion: Incident statin use was not associated with increased MAARI incidence and may be associated with lower incidence of MAARI in those with less comorbidity. This study thus offers reassurance regarding the effectiveness of the influenza vaccine in statin users.