The multivariable analysis also revealed a similar increased risk of stroke in women (adjusted baseline comorbid conditions, individual components of the score, and warfarin treatment.372 There was a signifi- cant (P=0.02) interaction of age with sex, with the increased stroke risk confined to women aged 75 years. The age-sex interaction on stroke risk in patients with AF was again con- firmed recently in a large Swedish nationwide drug registry Interestingly, warfarin use was associated with greater stroke reduction in women (60%; RR, 0.4; 95% CI, Appropriateness of Anticoagulation by Sex The appropriateness of anticoagulation in women with AF <65 years of age with no other major or clinically relevant risk factors is controversial. The European Society of Cardiology recommends anticoagulation for patients with AF and a -VASc score 1.387 The Canadian Cardiovascular Society recommends anticoagulation for AF patients with a According to these guidelines, anticoag- ulation would be recommended for all women with AF alone (and no other risk factors). Two large observational studies provide some guidance. The Swedish study (n=100802) found that the risk of stroke among patients with AF aged 65 years without risk fac- tors was comparably low in both women (0.7%) and men Another nationwide study from Denmark that included 73538 patients with AF looked at the short- and long-term risk of thromboembolic events by combining the risk factors included in CHA2 The authors found that female sex alone was the weaker risk factor, showing a nonsignificant increase in the risk of thromboembolic events 0.70 1.06) and 10-year (0.82; 95% CI, 0.68 1.00) follow-up. The increased risk of thromboembolic events rose in women The AHA provides recommendations based on CHADS2 . 