Background: Implementation of appropriate oral anticoagulant treatment for the prevention of stroke in very elderly patients with atrial fibrillation is challenging because of concerns regarding bleeding.
Methods: We conducted a phase 3, multicenter, randomized, double-blind, placebo-controlled, event-driven trial to compare a once-daily 15-mg dose of edoxaban with placebo in elderly Japanese patients (≥80 years of age) with nonvalvular atrial fibrillation who were not considered to be appropriate candidates for oral anticoagulant therapy at doses approved for stroke prevention. The primary efficacy end point was the composite of stroke or systemic embolism, and the primary safety end point was major bleeding according to the definition of the International Society on Thrombosis and Haemostasis.
Results: A total of 984 patients were randomly assigned in a 1:1 ratio to receive a daily dose of 15 mg of edoxaban (492 patients) or placebo (492 patients). A total of 681 patients completed the trial, and 303 discontinued (158 withdrew, 135 died, and 10 had other reasons); the numbers of patients who discontinued the trial were similar in the two groups. The annualized rate of stroke or systemic embolism was 2.3% in the edoxaban group and 6.7% in the placebo group (hazard ratio, 0.34; 95% confidence interval [CI], 0.19 to 0.61; P<0.001), and the annualized rate of major bleeding was 3.3% in the edoxaban group and 1.8% in the placebo group (hazard ratio, 1.87; 95% CI, 0.90 to 3.89; P = 0.09). There were substantially more events of gastrointestinal bleeding in the edoxaban group than in the placebo group. There was no substantial between-group difference in death from any cause (9.9% in the edoxaban group and 10.2% in the placebo group; hazard ratio, 0.97; 95% CI, 0.69 to 1.36).
Conclusions: In very elderly Japanese patients with nonvalvular atrial fibrillation who were not appropriate candidates for standard doses of oral anticoagulants, a once-daily 15-mg dose of edoxaban was superior to placebo in preventing stroke or systemic embolism and did not result in a significantly higher incidence of major bleeding than placebo. (Funded by Daiichi Sankyo; ELDERCARE-AF ClinicalTrials.gov number, NCT02801669.).
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