Who Will Do Well on Warfarin? Does It Matter?

In the ARISTOTLE trial, apixaban, a new oral factor Xa inhibitor, was superior to warfarin for reduction of stroke, mortality, and bleeding rates in patients with atrial fibrillation (JW Cardiol 2011 Aug 29). However, the average time in therapeutic range (TTR) of international normalized ratio (INR) in the warfarin group was low (66%). To compare apixaban and warfarin outcomes in relation to factors affecting TTR, investigators …