AIMS: The risk of stroke in patients with atrial fibrillation (AF) increases with age. In the ARISTOTLE trial, apixaban when compared with warfarin reduced the rate of stroke, death, and bleeding. We evaluated these outcomes in relation to patient age. METHODS AND RESULTS: A total of 18 201 patients with AF and a raised risk of stroke were randomized to warfarin or apixaban 5 mg b.d. with dose reduction to 2.5 mg b.d. or placebo in 831 patients with ≥2 of the following criteria: age ≥80 years, body weight ≤60 kg, or creatinine ≥133 μmol/L. We used Cox models to compare outcomes in relation to patient age during 1.8 years median follow-up. Of the trial population, 30% were <65 years, 39% were 65 to <75, and 31% were ≥75 years. The rates of stroke, all-cause death, and major bleeding were higher in the older age groups (P < 0.001 for all). Apixaban was more effective than warfarin in preventing stroke and reducing mortality across all age groups, and associated with less major bleeding, less total bleeding, and less intracranial haemorrhage regardless of age (P interaction >0.11 for all). Results were also consistent for the 13% of patients ≥80 years. No significant interaction with apixaban dose was found with respect to treatment effect on major outcomes. CONCLUSION: The benefits of apixaban vs. warfarin were consistent in patients with AF regardless of age. Owing to the higher risk at older age, the absolute benefits of apixaban were greater in the elderly.

Boston University Medical Center Boston MA USA

Bristol Myers Squibb Princeton NJ USA

Cardiovascular Centre University Hospital Motol Prague Czech Republic

Department of Cardiology B Oslo University Hospital Oslo 0407 Norway

Department of Cardiology B Oslo University Hospital Oslo 0407 Norway Institute of Clinical Medicine University of Oslo Norway

Department of Medical Sciences Cardiology and Uppsala Clinical Research Center Uppsala University Uppsala Sweden

Division of Hematology University of Washington Seattle WA USA

Duke Clinical Research Institute Duke University Medical Center Durham NC USA

Faculty of Medicine Ankara University Ankara Turkey

G D'Annunzio Università Chieti and Fondazione Toscana G Monasterio Pisa Italy

Medical Department Hospital Unit West Herning Holstbro Denmark

National Institute of Cardiology Warsaw Poland

Ann Intern Med. 2014 Jun 17;160(12):JC7. doi: 10.7326/0003-4819-160-12-201406170-02007. PubMed

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