Increase seen in clinically relevant and major bleeding events, no reduction in stroke risk
FRIDAY, July 8 (HealthDay News) -- Combination antithrombotic therapy for patients with atrial fibrillation (AF) is associated with an increased risk of bleeding and no reduction in the risk of stroke, according to a study published in the July issue of Chest.
Deirdre A. Lane, Ph.D., of the University of Birmingham Centre for Cardiovascular Sciences in the United Kingdom, and colleagues analyzed data from 4,576 patients enrolled in the Evaluating the Use of SR34006 Compared to Warfarin or Acenocoumarol in Patients with AF (AMADEUS) trial. Participants were randomly allocated to receive 2.5 mg of idraparinux weekly (2,283) or Vitamin K antagonists (2,293). Of the total number of patients, 848 received antiplatelet therapy in addition to antithrombotic therapy (combination antithrombotic therapy).
The investigators found that a total of 572 (15.3 percent per year) clinically relevant bleeding and 103 (2.6 percent per year) major bleeding events occurred, for which a 2.3- to 2.5-fold increased risk, respectively, was found in patients receiving combination antithrombotic therapy when compared to those receiving anticoagulation therapy only. A significant increase in the risks of clinically relevant bleeding and major bleeding events was seen for those age 65 to 74 years (hazard ratio [HR], 1.44 and 2.26, respectively), age ≥ 75 years (HR, 1.59 and 4.19, respectively), and for participants treated with combination antithrombotic therapy (HR, 2.47 and 2.23, respectively). The combination antithrombotic therapy did not decrease the risk of ischemic stroke compared with anticoagulant therapy only (adjusted HR, 2.01).
"Combination antithrombotic treatment is justified only in patients with a clear indication that the benefit of adding antiplatelet therapy to anticoagulant treatment outweighs the increased risk of bleeding," the authors write.
Several of the study authors disclosed financial ties to the pharmaceutical industry, including Sanofi-Aventis, which funded the AMADEUS trial.
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