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Comparative clinical outcomes between direct oral anticoagulants and warfarin among elderly patients with non-valvular atrial fibrillation in the CMS medicare population


Atrial fibrillation (AF) prevalence increases with age; > 80% of US adults with AF are aged ≥ 65 years. Compare the risk of stroke/systemic embolism (SE), major bleeding (MB), net clinical outcome (NCO), and major adverse cardiac events (MACE) among elderly non-valvular AF (NVAF) Medicare patients prescribed direct oral anticoagulants (DOACs) VS warfarin. NVAF patients aged ≥ 65 years who initiated DOACs (apixaban, dabigatran, and rivaroxaban) or warfarin were selected from 01JAN2013-31DEC2015 in CMS Medicare data. Propensity score matching was used to balance DOAC and warfarin cohorts. Cox proportional hazards models estimated the risk of stroke/SE, MB, NCO, and MACE. 37,525 apixaban-warfarin, 18,131 dabigatran-warfarin, and 55,359 rivaroxaban-warfarin pairs were included. Compared to warfarin, apixaban (HR: 0.69; 95% CI 0.59-0.81) and rivaroxaban (HR: 0.82; 95% CI 0.73-0.91) had lower risk of stroke/SE, and dabigatran (HR: 0.88; 95% CI 0.72-1.07) had similar risk of stroke/SE. Apixaban (MB: HR: 0.61; 95% CI 0.57-0.67; NCO: HR: 0.64; 95% CI 0.60-0.69) and dabigatran (MB: HR: 0.79; 95% CI 0.71-0.89; NCO: HR: 0.84; 95% CI 0.76-0.93) had lower risk of MB and NCO, and rivaroxaban had higher risk of MB (HR: 1.08; 95% CI 1.02-1.14) and similar risk of NCO (HR: 1.04; 95% CI 0.99-1.09). Compared to warfarin, apixaban had a lower risk for stroke/SE, MB, and NCO; dabigatran had a lower risk of MB and NCO; and rivaroxaban had a lower risk of stroke/SE but higher risk of MB. All DOACs had lower risk of MACE compared to warfarin.

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