Apixaban compared favorably with warfarin in decreasing risk for stroke or systemic embolism among patients with atrial fibrillation, according to results from the ARISTOTLE trial.
The study also indicated greater absolute benefits from apixaban among older patients, due to an increased risk for these events.
The double blind, randomized trial included 18,201 patients with AF or atrial flutter and one or more risk factors for stroke or systemic embolism. Patients were randomly assigned at a 1:1 ratio to 5 mg apixaban (Eliquis, Bristol-Myers Squibb) twice daily or dose-adjusted warfarin. For patients with two or more of the following factors, the apixaban dose was adjusted to 2.5 mg twice daily: age at least 80 years, body weight ≤60 kg and/or serum creatinine levels ≥133 mcmol/L. The incidence of stroke, systemic embolism or all-cause mortality was compared according to patient age during a median 1.8 years of follow-up. Secondary safety outcomes included total and intracranial bleeding.
Of the study population, 30% were younger than 65 years, 39% were aged 65 to 75 years and 31% were aged at least 75 years. Patients were aged at least 80 years in 13% of cases. Annualized rates of stroke or systemic embolism increased with age, from 0.93% among those younger than 65 years to 1.86% to those aged at least 75 years. Both CV-related and all-cause mortality increased significantly with age, along with incidence of major bleeding and intracranial hemorrhage (P<.0001 for all).
Across all age groups, apixaban was more successful than warfarin in the prevention of stroke and systemic embolism (P=.11 for interaction with continuous age) and all-cause mortality (P=.43). Apixaban also yielded less major bleeding (P=.63 for interaction with continuous age), fatal bleeding or hemorrhagic stroke (P=.23) and intracranial hemorrhage, independent of age. Similar results were observed among patients aged at least 80 years. No significant interaction with age was observed on the effect of apixaban vs. warfarin for any of the evaluated outcomes.
“In this study, apixaban was shown to be superior to warfarin with respect to stroke prevention, bleeding complications and mortality, with consistency across all age groups,” the researchers wrote. “Taken together with the lack of need for coagulation monitoring and the few drug interactions, apixaban appears to be an attractive alternative for elderly patients with AF.”
Disclosure: Please see the full study for a list of relevant disclosures.