Affiliation:
1. Clinical Epidemiology Program Veterans Affairs Medical Center White River Junction Vermont USA
2. PBM, Center for Medication Safety US Department of Veterans Affairs Hines Illinois USA
3. Department of Health Services, Policy, and Practice Brown University School of Public Health Providence Rhode Island USA
4. Global Medical Evidence Generation Sanofi Swiftwater Pennsylvania USA
5. Vaccine and Drug Evaluation Centre, Department of Community Health Sciences University of Manitoba Winnipeg Manitoba Canada
Abstract
ABSTRACTBackgroundInfluenza may contribute to coronary/cerebrovascular events and exacerbate underlying conditions.MethodsWe used self‐controlled case series (SCCS) design to analyze data from US Veterans ≥18 years with coronary/cerebrovascular or exacerbation event +/−1 year of lab‐confirmed influenza (LCI) during 2010–2018. We estimated the incidence ratio (IR) (95% CI) of the event for risk interval (Days 1–7 post‐LCI) versus control interval (all other times +/−1 year of LCI) with fixed‐effects conditional Poisson regression. We included biomarker data for mediation analysis.ResultsWe identified 3439 episodes with coronary/cerebrovascular‐related hospitalizations. IRs (95% CI) for LCI risk versus control interval were STEMI 0.6 (0.1, 4.4), NSTEMI 7.3 (5.8, 9.2), ischemic stroke 4.0 (3.0, 5.4), hemorrhagic stroke 6.2 (3.4, 11.5), and coronary spasm 1.3 (0.5, 3.0). IR significantly increased for NSTEMI and ischemic stroke among those ≥ 65 years. IR for NSTEMI and ischemic stroke dropped 26% and 10%, respectively, when white blood cell (WBC) and platelet count were considered. LCI was significantly associated with exacerbation of preexisting asthma, chronic obstructive pulmonary disease, and congestive heart failure.ConclusionsWe found significant association between LCI and hospitalization for NSTEMI, ischemic stroke, and hemorrhagic stroke, the latter possibly due to unaccounted time‐varying confounding in SCCS design.