1. For older adults with atrial fibrillation (AF), warfarin, dabigatran, and rivaroxaban are associated with higher risk of ischemic stroke and major bleeding events compared to apixaban, and this risk is higher for patients with dementia.
Evidence Rating Level: 2 (Good)
Guidelines for adults living with atrial fibrillation (AF) recommend anticoagulation therapy due to the increased risk of embolic stroke. While the effectiveness and safety profile of oral anticoagulants (OACs) have been studied across many demographics, patients with dementia have often been excluded from trials, likely due to the complexity of informed consent. Therefore, this comparative effectiveness study examined the ischemic stroke risk and risk of major bleeding events on various OACs for AF patients 65 years and older, stratified by dementia status. The study made use of claims data in the United States and identified patients filling a new prescription for an OAC, with no other indication for anticoagulation apart from AF, enrolled in coverage for at least 1 year. 3 cohorts were made, comparing warfarin, dabigatran, and rivaroxaban respectively to apixaban, the OAC generally preferred amongst older adults. The composite end point outcome was ischemic stroke or major bleeding events over 6 months follow-up. In total, there were 1,160,462 patients in the study, 7.9% of whom had dementia. The results showed that compared to apixaban, warfarin patients had higher rates of the composite outcome (adjusted hazard ratio 1.5, 95% CI 1.3-1.7), and the same was true for dabigatran (aHR 1.5, 95% CI 1.2-2.0) and rivaroxaban (aHR 1.3, 95% CI 1.1-1.5). When examining the rate differences (RDs) of the composite outcome per 1000 person-years across all 3 cohorts, the RD estimates were consistently higher for patients with dementia compared to those without. For the warfarin vs apixaban cohort, the RD estimate was 29.8 (95% CI 18.4-41.1) events compared to 16.0 (95% CI 13.6-18.4) events in patients with and without dementia respectively; for dabigatran vs apixaban, it was 29.6 (95% CI 11.6-47.6) events compared to 5.8 (95% CI 1.1-10.4) events; and for the rivaroxaban vs apixaban cohort, it was 20.5 (95% CI 9.99-31.1) compared to 15.9 (95% CI 11.4-20.3) events. Overall, this study demonstrated that apixaban has lower risk of ischemic stroke and major bleeding events compared to other OACs, and that this benefit is particularly more pronounced in patients with dementia.
Image: PD
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