Evaluation of Excessive Anticoagulation in a Group Model Health Maintenance Organization

Abstract
ORAL anticoagulant therapy has demonstrated clinical effectiveness for several indications, including the prevention and treatment of thromboembolism and the prevention of systemic embolism in patients with artificial heart valves or atrial fibrillation. Consequently, each year more than 1 million patients are treated with warfarin sodium in the United States.1 The main complication associated with warfarin therapy is bleeding.2 In a summary of various studies involving oral anticoagulant therapy, the average annual frequency of total, major, and fatal bleeding was estimated to be 9.6%, 3.0%, and 0.6%, respectively.3