Incidence, Risk Factors, and Outcomes in Stressor-Associated Atrial Fibrillation: Insights From the VITAL-AF Trial

BACKGROUND: Stressor-associated atrial fibrillation (AF), defined as newly diagnosed AF in the setting of a reversible physiological stressor, is common. However, risk factors, outcomes, and current management practices remain poorly understood. METHODS: We analyzed data from VITAL-AF, a pragmatic, cluster-randomized AF screening trial conducted in 2018 and 2019 comprising adults ≥65 years of age across 16 primary care practices affiliated with Massachusetts General Hospital. All participants had longitudinal follow-up for adjudicated incident AF (including whether stressor-associated versus nonstressor-associated ["primary"]) and clinical outcomes. We compared associations between clinical AF risk factors and incident AF group (stressor-associated versus primary) using Fine-Gray models handling death and each AF group as competing risks. We also quantified oral anticoagulant initiation rates after AF diagnosis. We then fit Cox proportional hazards models to quantify associations between incident AF group (as a time-varying covariate) and a composite end point of major bleeding, stroke, and all-cause mortality, with adjustment for CHA₂DS₂-VASc (congestive heart failure, hypertension, age >74, diabetes, stroke or transient ischemic attack or thromboembolism, vascular disease, age 65-74, sex category; stroke) and ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation; bleeding) scores and time-varying oral anticoagulant exposure. RESULTS: <0.001). The incidence of the composite end point was 2.30 per 100 person-years (95% CI, 2.17-2.44) for no AF, 15.09 (95% CI, 12.22-18.42) for primary AF, and 22.71 (95% CI, 16.91-29.87) for stressor-associated AF. In adjusted models and using no AF as the referent, both primary AF (hazard ratio [HR], 3.91 [95% CI, 2.89-5.28]) and stressor-associated AF (HR, 6.13 [95% CI, 4.31-8.72]) were associated with substantially higher risk of the composite end point. CONCLUSIONS: Among >30 000 primary care patients with adjudicated AF events, nearly one-third of incident AF cases were stressor associated. Despite similar risk factor profiles and comparably high rates of adverse outcomes, oral anticoagulant initiation is lower when AF is stressor associated. Future work is needed to define optimal approaches to prevention, surveillance, and management of stressor-associated AF.