Edoxaban versus Warfarin in high-risk patients with atrial fibrillation: A comprehensive analysis of high-risk subgroups

Background: To compare the efficacy and safety of edoxaban vs warfarin in high-risk subgroups. Methods: ENGAGE AF-TIMI 48 was a multicenter randomized, double-blind, controlled trial in 21,105 patients with atrial fibrillation (AF) within 12 months and CHADS₂ score >2 randomized to higher-dose edoxaban regimen (HDER) 60 mg/reduced 30 mg, lower-dose edoxaban regimen (LDER) 30 mg/reduced 15 mg, or warfarin, and followed for 2.8 years (median). The primary outcome for this analysis was the net clinical outcome (NCO), a composite of stroke/systemic embolism events, major bleeding, or death. Multivariable risk-stratification analysis was used to categorize patients by the number of high-risk features. Results: The annualized NCO rates in the warfarin arm were highest in patients with malignancy (19.2%), increased fall risk (14.0%), and very-low body weight (13.5%). The NCO rates increased with the numbers of high-risk factors in the warfarin arm: 4.5%, 7.2%, 9.9% and 14.6% in patients with 0 to 1, 2, 3, and >4 risk factors, respectively (P_trend <0.001). Versus warfarin, HDER was associated with significant reductions of NCO in most of the subgroups: elderly, patients with moderate renal dysfunction, prior stroke/TIA, of Asian race, very-low body weight, concomitant single antiplatelet therapy, and VKA-naïve. With more high-risk features (0->4+), the absolute risk reductions favoring edoxaban over warfarin increased: 0.3%->2.0% for HDER; 0.4%->3.4% for LDER vs warfarin (P = .065 and P < .001, respectively). Conclusions: While underuse of anticoagulation in high-risk patients with AF remains common, substitution of effective and safer alternatives to warfarin, such as edoxaban, represents an opportunity to improve clinical outcomes.