Enhanced dose–response to warfarin in W, due to lower mean BMI and SRDs in warfarin metabolism via P450 enzymesSignificantly higher free plasma levels in W; they require lower doses of warfarin than M to maintain the INRMeta-analysis (6 RCTs; n = 63 602; 28% W): W with AF on warfarin were at higher residual risk of CVA/SE than M (P = 0.001)W treated with warfarin spend more time outside the therapeutic range than M. This evidence concerns the gene CYP2B6 and atrial fibrillation.