Oral Anticoagulation and the Risk of Stroke or Death in Patients With Atrial Fibrillation and One Additional Stroke Risk Factor The Loire Valley Atrial Fibrillation Project

BACKGROUND: It remains uncertain whether patients with atrial fibrillation (AF) and a single additional stroke risk factor (congestive heart failure, hypertension, age >= 75 years, diabetes mellitus, prior stroke or thromboembolism, vascular disease, age 65-74 years, and sex category [CHA(2)DS(2)-VASc] score = 1 in men, 2 in women) should be treated with oral anticoagulation (OAC). We investigated the risk of ischemic stroke, systemic embolism, and death in a community-based cohort of unselected patients with AF with zero to one stroke risk factor based on the CHA2DS2-VASc score. METHODS: Among 8,962 patients with AF seen between 2000 and 2010, 2,177 (24%) had zero or one additional stroke risk factor, of which 53% were prescribed OAC. RESULTS: Over a follow-up of 979 +/- 1,158 days, 151 (7%) had a major adverse event (stroke/systemic thromboembolism/death). Prescription of OAC was not associated with a better prognosis for stroke/systemic thromboembolism/death for patients in the "low-risk" category (ie, CHA(2)DS(2)-VASc score = 0 for men or 1 for women; adjusted hazard ratio [HR], 0.68; 95% CI, 0.35-1.31; P = .25). OAC use was independently associated with a better prognosis in patients with AF with a single additional stroke risk factor (ie, CHA(2)DS(2)-VASc score = 1 in men, 2 in women; adjusted HR, 0.59; 95% CI, 0.40-0.86; P = .007). CONCLUSIONS: Among patients with AF with a single additional stroke risk factor (CHA(2)DS(2)-VASc score = 1 in men, 2 in women), OAC use was associated with an improved prognosis for stroke/systemic thromboembolism/death.