Do Patients' Stroke and Bleeding Risks Affect Apixaban's Advantage over Warfarin?
In an ARISTOTLE subanalysis, apixaban maintained its edge across the range of risk scores in patients with atrial fibrillation, but stronger confirmation is needed.
In the manufacturer-sponsored ARISTOTLE trial, apixaban outperformed warfarin for prevention of stroke or systemic embolism in 18,201 patients with atrial fibrillation (JW Cardiol Aug 29 2011). In a secondary analysis of the ARISTOTLE data, investigators have analyzed whether the results differed according to patients' scores on CHADS2 (available online), CHA2DS2VASc (available online), and HAS-BLED (available online), models commonly used to predict risks for stroke and bleeding.
Compared with warfarin, apixaban was associated with a significant reduction in stroke or systemic embolism that was unaffected by risk for stroke or for bleeding. Rates of major bleeding were lower in apixaban recipients than in warfarin recipients, with no significant differences among risk-score groups. The relative reduction in risk for intracranial bleeding with apixaban was greater in patients with HAS-BLED scores of 3 or higher (hazard ratio, 0.22; 95% confidence interval, 0.10–0.48; without significant interaction) than in those with scores of 0–1.
Lopes RD et al. Efficacy and safety of apixaban compared with warfarin according to patient risk of stroke and of bleeding in atrial fibrillation: A secondary analysis of a randomised controlled trial. Lancet 2012 Oct 2; [e-pub ahead of print].
Vassiliou VS and Flynn PD. Apixaban in atrial fibrillation: Does predicted risk matter? Lancet 2012 Oct 2; [e-pub ahead of print].