This Figure shows TTR data from the ACTIVE (Atrial fibrillation Clopidogrel Trial with Irbesartan for prevention of Vascular Events) W trial,[87] assessing antiplatelet therapy with aspirin plus clopidogrel (Plavix; Bristol-Myers Squibb/Sanofi) versus warfarin in 7554 patients with AFib and at least one risk factor for stroke.  The Figure shows that if the time in therapeutic range (TTR) is <65%, there was no difference in event rates between antiplatelet and anticoagulant therapy.  For patients with TTR ≥65%, however, the relative risk of events was more than double (RR=2.14, p=0.0001) for patients on aspirin plus clopidogrel instead of warfarin. In other words, there is a dramatic benefit in favor of the oral anticoagulant agent, but only when warfarin is administered correctly; being on warfarin, but not in the therapeutic range consistently, is not effective therapy.

Reiffel JA. Am J Med 2013; 126: 00-00.