Abstract

Background: Atrial fibrillation (AF) is a major risk factor (RF) for ischemic stroke. Its prevalence and prognostic impact in patients with atherothrombosis are unclear. Methods: Risk factors, drug usage, and 1-year cardiovascular (CV) outcomes (CV death, myocardial infarction [MI], and stroke) were compared in AF and non-AF patients from the REduction of Atherothrombosis for Continued Health (REACH) Registry, an international, prospective cohort of 68,236 stable outpatients with established atherothrombosis or ≥3 atherothrombotic RFs. Results: Atrial fibrillation and 1-year follow-up data are available for 63,589 patients. The prevalence of AF was, 12.5%, 13.7%, 11.5%, and 6.2% among coronary artery disease, CV disease, peripheral artery disease, and RF-only patients, respectively. Of the 6,814 patients with AF, 6.7% experienced CV death, nonfatal MI, or nonfatal stroke within a year. The annual incidence of nonfatal stroke (2.4% vs 1.6%, P < .0001) and unstable angina (6.0% vs 4.0%, P < .00001) was higher, and CV death was more than double (3.2% vs 1.4%, P < .0001), in AF versus non-AF patients. In these patients with or at high risk of atherothrombosis, most patients with AF received antiplatelet agents, but only 53.1% were treated with oral anticoagulants. Even with high CHADS2 (congestive heart failure, hypertension, aging, diabetes mellitus, and stroke) scores, anticoagulant use did not exceed (59%). The rate of bleeding requiring hospitalization was higher in AF versus non-AF patients (1.5% vs 0.8%, P < .0001), possibly related to the more frequent use of anticoagulants (53.1% vs 7.1%). Conclusions: Atrial fibrillation is common in patients with atherothrombosis, associated with more frequent fatal and nonfatal CV outcomes, and underuse of oral anticoagulants. © 2008 Mosby, Inc. All rights reserved.