Benefit of Anticoagulation Unlikely in Patients With Atrial Fibrillation and a CHA2DS2-VASc Score of 1

BACKGROUND: Patients with atrial fibrillation (AF) and ≥1 point on the stroke risk scheme CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category) are considered at increased risk for future stroke, but the risk associated with a score of 1 differs markedly between studies. OBJECTIVES: The goal of this study was to assess AF-related stroke risk among patients with a score of 1 on the CHA2DS2-VASc. METHODS: We conducted this retrospective study of 140,420 patients with AF in Swedish nationwide health registries on the basis of varying definitions of "stroke events." RESULTS: Using a wide "stroke" diagnosis (including hospital discharge diagnoses of ischemic stroke as well as unspecified stroke, transient ischemic attack, and pulmonary embolism) yielded a 44% higher annual risk than if only ischemic strokes were counted. Including stroke events in conjunction with the index hospitalization for AF doubled the long-term risk beyond the first 4 weeks. For women, annual stroke rates varied between 0.1% and 0.2% depending on which event definition was used; for men, the corresponding rates were 0.5% and 0.7%. CONCLUSIONS: The risk of ischemic stroke in patients with AF and a CHA2DS2-VASc score of 1 seems to be lower than previously reported.