Atrial fibrillation: prevalence in a large database of primary care patients in Brazil

AIMS: Although an increasing prevalence of atrial fibrillation (AF) has been reported worldwide, there are few studies from low- and middle-income countries. Our objective is to assess the prevalence of AF and the associated medical conditions in Brazilian primary care patients. METHODS AND RESULTS: This is an observational retrospective study. Patients ≥5 years of age from primary care centres of 658 municipalities in Minas Gerais, Brazil, who performed digital electrocardiograms (ECGs) by a public telehealth service in 2011 were assessed. Clinical data were self-reported, and ECGs were interpreted by a team of trained cardiologists using standardized criteria. To assess the relation between clinical characteristics and AF, odds ratios were estimated by logistic regression. A total of 262 685 primary care patients were included, mean (SD) age of 50.3 (19.3) years, 59.6% female. Hypertension was reported in 32.0%, family history of coronary heart disease in 15.0%, diabetes in 5.4%, hyperlipidaemia in 2.8%, Chagas disease in 2.9%, and 7.1% reported current smoking. The prevalence of AF was 1.8% overall: 2.4% in men (ranging from 0.001% from 5-19 years old to 14.6% in nonagenarians) and 1.3% in women (ranging from 0.001% from 5-19 years old to 8.7% in nonagenarians) (P < 0.001). The prevalence of AF increased with advancing age. The comorbidities associated with AF were Chagas disease, previous myocardial infarction, hypertension, and chronic obstructive pulmonary disease. Vitamin K antagonist use was reported by 1.5% of patients. CONCLUSION: The prevalence and age distribution of AF were similar to studies in high-income countries. The proportion of patients who reported the use of anticoagulants was alarmingly low. Our findings point out the necessity to formulate effective treatment strategies for AF in Brazilian primary care settings.