Apixaban Versus Warfarin in Patients With Atrial Fibrillation

Study Questions:

Is the factor Xa inhibitor apixaban as effective as warfarin for preventing strokes in patients with atrial fibrillation?


In this double-blind, randomized clinical trial, 18,201 patients (mean age 70 years) with AF and ≥1 risk factor for stroke were randomly assigned to therapy with apixaban, 5 mg twice daily, or adjusted-dose warfarin with a target international normalized ratio (INR) of 2-3. The median duration of follow-up was 1.8 years. The primary outcome was ischemic/hemorrhagic stroke and systemic embolism.


The primary outcome occurred 21% less often in the apixaban group than in the warfarin group (1.27%/year vs. 1.6%/year, respectively). The rates of major bleeding (2.1% vs. 3.1%), hemorrhagic stroke (0.24 vs. 0.47%), and all-cause mortality (3.5% vs. 3.9%) also were significantly lower in the apixaban group than the warfarin group.


The authors concluded that apixaban is superior to warfarin for prevention of stroke and systemic embolism in the setting of AF, and is associated with a lower risk of death.


As is the case with dabigatran, apixaban is more convenient than warfarin because it does not require monitoring of the INR and because its anticoagulation effect is not influenced by dietary factors. A comparison of clinical trial results suggests that apixaban may be superior to warfarin in regards to safety and efficacy to a greater degree than dabigatran. Apixaban is not yet available in the United States and is approved in Europe for prevention of deep venous thrombosis after orthopedic procedures such as hip or knee replacement. It is anticipated that apixaban will be approved in the United States for stroke prevention in patients with AF in the next 12 months.

Clinical Topics: Anticoagulation Management, Dyslipidemia, Vascular Medicine, Lipid Metabolism, Novel Agents

Keywords: Stroke, Follow-Up Studies, Warfarin, Orthopedic Procedures, Risk Factors, Pyrazoles, Europe, Fibrinolytic Agents, International Normalized Ratio, Intracranial Hemorrhages, beta-Alanine, Benzimidazoles, Venous Thrombosis, Factor Xa, Embolism, Pyridones, United States

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