Abstract 261: Applying Clinical Trial Data to Real-World: Apixaban, Dabigatran, and Rivaroxaban
BACKGROUND: Data from randomized controlled trials and a real-world sample of non-valvular atrial fibrillation patients were combined to estimate the absolute effect of each new oral anticoagulant (NOAC, apixaban, dabigatran, and rivaroxaban) versus warfarin on stroke and major bleeding rates in real-world clinical practice. METHODS: Non-valvular atrial fibrillation patients were selected from Medco healthplans during 2007-2010. Reference rates for stroke and major bleeding excluding intracranial hemorrhage (to avoid double counting) were calculated for real-world Medco patients during warfarin use. Real-world event rates for NOACs were estimated by multiplying the corresponding relative risk from the randomized clinical trials by each reference rate. Absolute risk reductions and numbers needed to treat (NNT) or numbers needed to harm (NNH) for each NOAC vs. warfarin were then estimated. Reduction in net clinical outcome was calculated by summing the absolute risk reductions for stroke and major bleeding excluding intracranial hemorrhage for each NOAC versus warfarin. RESULTS: Each NOAC resulted in a reduction in stroke events compared with warfarin in the real-world (TABLE). Apixaban was the only NOAC to reduce the rate of major bleeding excluding intracranial hemorrhage compared with warfarin. The NNT to avoid one net clinical outcome (stroke plus major bleeding excluding intracranial hemorrhage) per year was 32 and 84 for apixaban and dabigatran, respectively. Rivaroxaban resulted in an increase in net clinical outcome (NNH=166). CONCLUSIONS: If relative risk reductions from randomized clinical trials persist in the real-world, apixaban would result in the greatest clinical benefit versus warfarin of all NOACs in terms of stroke and major bleeding excluding intracranial hemorrhage events avoided.