Abstract
BACKGROUND: Patients with atrial fibrillation (AF) are at a substantial risk of ischemic stroke. The CHA₂DS₂-VASc score predicts the risk of thromboembolism, but its role in predicting major bleeding in patients taking oral anticoagulants is unclear. METHODS: We used the National Health Insurance Research Database (NHIRD) of Taiwan to identify patients with AF from 2010 to 2016. They were divided into four groups according to the oral anticoagulants. The outcomes were ischemic stroke/systemic thromboembolism, and major bleeding. RESULTS: A total of 279,776 patients were identified. Ischemic stroke or systemic embolism events were observed in 1.73%, 3.62%, 4.36%, and 5.02% of the patients in the apixaban, rivaroxaban, dabigatran, and warfarin groups, respectively. Major bleeding was recorded in 1.18%, 2.66%, 3.23%, and 4.70% of the patients in the apixaban, rivaroxaban, dabigatran, and warfarin groups, respectively. The highest rates for both ischemic stroke and bleeding events occurred in the patients with a CHA₂DS₂-VASc score of five or more. CONCLUSION: Non-valvular AF patients with high CHA₂DS₂-VASc scores are susceptible to both systemic thromboembolism and major bleeding. The trend was consistently observed in patients who took non-vitamin K oral anticoagulants (NOACs) or warfarin. NOACs might be potentially more effective in reducing overall events.