Efficacy and safety of apixaban compared with aspirin in the elderly: A subgroup analysis from the AVERROES trial

Abstract

Background: increasing age is associated with a higher prevalence of atrial fibrillation (AF), and higher risks of stroke andbleeding. We report the effects of apixaban versus acetylsalicylic acid (ASA) in older patients (≥75 years and ≥85 years) comparedwith younger patients with AF unsuitable for vitamin K antagonists.Methods: AVERROES (Apixaban Versus ASA to Prevent Stroke In AF Patients Who Have Failed or Are Unsuitable forVitamin K Antagonist Treatment) trial (n = 5,599) included 1,898 patients ≥75 years and 366 patients ≥85 years. We comparedthe baseline characteristics and effects of apixaban compared with aspirin on clinical outcomes by age.Results: compared with aspirin, apixaban was more efficacious for preventing strokes and systemic embolism in patients ≥85years (absolute rate [AR] 1%/year on apixaban versus 7.5%/year on aspirin; hazard ratio [HR] 0.14, 95% confidence interval[CI] 0.02-0.48) compared with younger patients (AR 1.7%/year on apixaban versus 3.4%/year on aspirin; HR 0.50, 95% CI0.35-0.69) (P-value for interaction = 0.05). Major haemorrhage was higher in patients ≥85 years compared with youngerpatients but similar with apixaban versus aspirin in both young and older individuals (4.9%/year versus 1.0%/year on aspirinand 4.7%/year versus 1.2%/year on apixaban) with no significant treatment-by-age interaction (P-value = 0.65).Conclusions: older patients with AF are at particularly high risk of stroke if given aspirin and have substantially greater relativeand absolute benefits from apixaban compared with younger patients with no greater risk of haemorrhage.Clinical Trial Registration: ClinicalTrials.gov number: NCT00496769. URL: https://clinicaltrials.gov/ct2/show/NCT00496769.