Variations in cause and management of atrial fibrillation in a prospective registry of 15 400 emergency department patients in 46 countries: The RE-LY atrial fibrillation registry

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia; however, little is known about patients in a primary care setting from high-, middle-, and low-income countries. Methods and results: This prospective registry enrolled patients presenting to an emergency department with AF at 164 sites in 46 countries representing all inhabited continents. Patient characteristics were compared among 9 major geographic regions. Between September 2008 and April 2011, 15 400 patients were enrolled. The average age was 65.9, standard deviation 14.8 years, ranging from 57.2, standard deviation 18.8 years in Africa, to 70.1, standard deviation 13.4 years in North America, P<0.001. Hypertension was globally the most common risk factor for AF, ranging in prevalence from 41.6% in India to 80.7% in Eastern Europe, P<0.001. Rheumatic heart disease was present in only 2.2% of North American patients, in comparison with 21.5% in Africa and 31.5% in India, P<0.001. The use of oral anticoagulation among patients with a CHADS₂ score of ≥2 was greatest in North America (65.7%) but was only 11.2% in China, P<0.001. The mean time in the therapeutic range was 62.4% in Western Europe, 50.9% in North America, but only between 32% and 40% in India, China, Southeast Asia, and Africa, P<0.001. Conclusions: There is a large global variation in age, risk factors, concomitant diseases, and treatment of AF among regions. Improving outcomes globally requires an understanding of this variation and the conduct of research focused on AF associated with different underlying conditions and treatment of AF and predisposing conditions in different socioeconomic settings.