Prevalence of Atrial Fibrillation, Oral Anticoagulation Prescription and Associated Factors in Brazilian Older Adults

Abstract

INTRODUCTION: Atrial fibrillation increases five times the risk of stroke. Anticoagulation reduces the incidence of cerebrovascular events. However, many patients do not receive thromboprophylaxis. OBJECTIVES: To estimate the prevalence of atrial fibrillation in the older patients at a Brazilian university hospital and the proportion of anticoagulation prescription. Secondary objectives were to identify the therapeutic options, the main reasons for non-prescription and the factors associated with ineffectiveness or lack of treatment. METHODS: This was a cross-sectional study with a consecutive sample of 1,630 outpatients selected at Hospital de Clínicas de Porto Alegre between April and June of 2017. Atrial fibrillation was identified in 220 (13.50%) individuals. Medical records from 145 patients were accessed, followed by a telephone interview. The association between variables and outcomes was checked using the Mann-Whitney's U Test and a chi-squared test. RESULTS: The prevalence of atrial fibrillation was 13.50%. Anticoagulation therapy was prescribed in 77.93% of cases. In 76.11% of patients, warfarin was the chosen drug. There was a tendency towards no prescription in patients with previous bleeding (RR = 2.32; 95%CI 0.95 – 5.64; p = 0.06) and falls (RR = 2.02; 95%CI 0.82 – 5.03; p = 0.08). We found an association between reduced functional capacity (Barthel's Activities of Daily Living Score < 80) and higher rate of anticoagulation in therapeutic target (RR = 0.22; 95%CI 0.06 – 0.87; p = 0.04). CONCLUSION: The prevalence of atrial fibrillation in this population was 13.50% and in 77.93% of cases anticoagulant were prescribed. Functional impairment was associated with a higher rate of anticoagulation in therapeutic target.

Keywords

• atrial fibrillation
• anticoagulants
• prevalence
• geriatrics
• cerebral infarction