Non-vitamin K antagonist oral anticoagulants in very elderly east Asians with atrial fibrillation: A nationwide population-based study.

Background: The evidence of effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (NOACs) among elderly East Asians is limited.

Objectives: We aimed to describe the effectiveness and safety outcomes associated with NOACs and warfarin among elderly Koreans aged ≥80 years.

Methods: Using the Korean Health Insurance Review and Assessment service database, patients with atrial fibrillation (AF) who were naïve to index oral anticoagulant between 2015 and 2017 were included in this study (20,573 for NOACs and 4086 for warfarin). Two treatment groups were balanced using the inverse probability of treatment weighting (IPTW) method. The clinical outcomes including ischemic stroke, major bleeding including intracranial hemorrhage (ICH) and gastrointestinal bleeding (GIB), and a composite of these outcomes were evaluated.

Results: Compared to warfarin, NOACs were associated with lower risks of ischemic stroke (hazard ratio 0.74 [95% confidence interval 0.62-0.89]), and composite outcome (0.78 [0.69-0.90]). NOACs showed nonsignificant trends towards to lower risks of GIB and major bleeding than warfarin. The risk of ICH of NOAC group was comparable with the warfarin group. Among NOACs, apixaban and edoxaban showed better composite outcomes than warfarin. Among the clinical outcomes, only ischemic stroke and the composite outcome had a significant interaction with age subgroups (80-89 years and ≥90 years, P-for-interaction = .097 and .040, respectively).

Conclusion: NOACs were associated with lower risks of ischemic stroke and the composite outcome (ischemic stroke and major bleeding) compared to warfarin in elderly East Asians. Physicians should be more confident in prescribing NOACs to elderly East Asians with AF.