Anticoagulation in women with non-valvular atrial fibrillation in the stroke prevention using an oral thrombin inhibitor (SPORTIF) trials

Aims The risk of stroke is greater among women with atrial fibrillation (AF) than men. Warfarin protects against stroke, but treatment-related bleeding occurs more often in women than in men. Methods and results SPORTIF III (open label, n=3410) and V (double-blind, n=3922) included 2257 women with AF and one or more stroke risk factors randomized to warfarin [target international normalized ratio (INR) 2.0-3.0] or ximelagatran (36 mg twice daily). Primary outcomes were all stroke (ischaemic/haemorrhagic) and systemic embolic event. Women were older, on average, than men, 73.4 +/- 8.0 vs. 69.8 +/- 9.0 years (P < 0.0001). More women were > 75-years old and women had more risk factors than men had (P < 0.0001). The INR on warfarin (mean 2.5 +/- 0.7) was within target range for 67% of follow-up regardless of gender. Women more often developed primary events [2.08%/year, 95% confidence interval (CI) 1.60-2.56%/year vs. 1.44%/year, 95% CI 1.18-1.71%/year in men; P=0.016). Major bleeding rates were similar (P=0.766) but women experienced more overall (major/minor) bleeding (P < 0.001). Warfarin was associated with more overall bleeding in both genders and more major bleeding in women than in men (P=0.001). Conclusion When compared with men with AF, women in these studies were older and had more stroke risk factors. Women were more prone to anticoagulant-related bleeding; the higher rate of thrombo-embolism among women was related to more frequent interruption of anticoagulant therapy.