Abstract
Background Atrial fibrillation (AF) increases the risk of stroke and extracranial systemic embolic events (SEEs), but little is known about the magnitude of the association of AF with SEE. Methods and Results This analysis included 14 941 participants of the ARIC (Atherosclerosis Risk in Communities) study (mean age, 54.2±5.8, 55% women, 74% White) without AF at baseline (1987-1989) followed through 2017. AF was identified from study ECGs, hospital discharges, and death certificates, while SEEs were ascertained from hospital discharges. CHA(2)DS(2)-VASc was calculated at the time of AF diagnosis. Cox regression was used to estimate associations of incident AF with SEE risk in the entire cohort, and between CHA(2)DS(2)-VASc score and SEE risk in those with AF. Among eligible participants, 3114 participants developed AF and 270 had an SEE (59 events in AF). Incident AF was associated with increased risk of SEE (hazard ratio [HR], 3.58; 95% CI, 2.57-5.00), after adjusting for covariates. The association of incident AF with SEE was stronger in women (HR, 5.26; 95% CI, 3.28-8.44) than in men (HR, 2.68; 95% CI, 1.66-4.32). In those with AF, higher CHA(2)DS(2)-VASc score was associated with increased SEE risk (HR per 1-point increase, 1.24; 95% CI, 1.05-1.47). Conclusions AF is associated with more than a tripling of the risk of SEE, with a stronger association in women than in men. CHA(2)DS(2)-VASc is associated with SEE risk in AF patients, highlighting the value of the score to predict adverse outcomes and guide treatment decisions in people with AF.