Influenza vaccination was associated with lower risks of incident atrial fibrillation (AFib) and multiple cardiovascular outcomes, according to an observational cohort study published July 11 in EHJ. The findings support vaccination as a potential AFib prevention strategy and underscore the need for randomized trials focused on AFib-related outcomes.

In the large retrospective study, Laurent Fauchier, MD, et al., used the international TriNetX Global Collaborative Federated Research Data Network, which included adults with a routine health care visit in 2022. Vaccination exposure was defined as influenza vaccination within the preceding year vs. no recorded vaccination.

Researchers performed 1:1 propensity score matching across 65 baseline variables to assess incident AFib, cardiovascular events and mortality, with subgroup analyses by age and baseline cardiovascular disease. The matched cohort included 276,888 patients in two well-balanced groups of 138,444 each (mean age, 53 years; 57% women).

During three years of follow-up, influenza vaccination was associated with a significant 20% lower risk of AFib (hazard ratio [HR], 0.80; p<0.0001). Annualized AFib incidence was lower among vaccinated vs. unvaccinated patients (0.9% vs. 1.1%).

Vaccination was also associated with lower risks of all-cause mortality (HR, 0.85), myocardial infarction (HR, 0.91), incident heart failure (HR, 0.92) and cardiovascular hospitalization (HR, 0.97). Benefits were consistent across age and cardiovascular disease subgroups, with no evidence of significant effect modification.

“…these findings support consideration of influenza vaccination as part of comprehensive cardiovascular and [AFib] prevention strategies in routine care,” write the authors. “…pragmatic randomized approaches – including cluster-randomized trials, registry-based studies or [health care] system-embedded interventions – may offer a more feasible strategy to efficiently evaluate [AFib]-related outcomes in broad populations.”