Evaluating the safety and effectiveness of direct oral anticoagulants compared with warfarin in very elderly patients with atrial fibrillation with and without low bodyweight.

ABSTRACT

BACKGROUND: Limited data exist on the safety and effectiveness of using direct oral anticoagulants (DOACs) in patients with atrial fibrillation aged 80 years or more with and without low bodyweight (LBW). OBJECTIVES: We aimed to evaluate the safety and effectiveness of using DOACs in this population compared with warfarin. METHODS: This retrospective active comparator new-user cohort study included veteran patients with atrial fibrillation who were newly initiated on either warfarin or DOACs between January 1, 2015, and January 1, 2021. The primary outcome was incidence of major bleeding and ischemic stroke. All outcomes were compared between treatment groups in 2 propensity score-matched cohorts of patients aged 80 years older with (AW) and without LBW (age-only cohort). Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs). RESULTS: Matched AW and age-only cohorts included 493 and 11 909 patients, respectively, in each of the DOAC and warfarin exposure groups. Greater than 90% were male, with a mean age of ∼87 years. The rate of major bleeding was lower in the DOAC group compared with warfarin in both the AW (aHR, 0.63; 95% CI, 0.46-0.87) and age-only cohorts (aHR, 0.58; 95% CI, 0.49-0.77). A significantly lower rate of ischemic stroke occurred in the DOAC group compared with warfarin in the AW cohort (aHR, 0.62; 95% CI, 0.45-0.84) and age-only cohort (aHR, 0.63; 95% CI, 0.58-0.68). CONCLUSION: DOAC use was associated with lower risk of major bleeding and ischemic stroke compared with warfarin in patients aged 80 years or older with and without LBW.