A comparison of three months of anticoagulation with extended anticoagulation for a first episode of idiopathic venous thromboembolism

People who have had one episode of venous thromboembolism should be treated with anticoagulant drugs for longer than three months. Venous thromboembolism occurs when blood clots form in the legs and travel to other parts of the body. Normally, when people have a first occurrence they are treated with anticoagulants for three months. Researchers randomly assigned 162 patients who had been treated for three months to continue taking warfarin or a placebo. Warfarin treatment beyond three months reduced the risk of a recurrence by 95% compared to placebo.