Thrombosis prophylaxis in the acutely ill medical patient: insights from the prophylaxis in medical patients with enoxaparin (MEDENOX) trial

The clinical benefit and cost-effectiveness of routine thromboprophylaxis in surgical patients has been well documented, but use of this approach in general medical patients remains controversial. Following is an overview of major insights from the prophylaxis in Medical patients with Enoxaparin (MEDENOX) trial, which was undertaken to evaluate the efficacy of 2 dosage regimens of the low-molecular-weight heparin enoxaparin for prevention of venous thromboembolism in acutely ill medical patients. MEDENOX was a prospective, double-blind, randomized, placebo-controlled trial, which enrolled 1,102 hospitalized patients from 68 centers in 9 countries. Patients were randomly assigned to receive 40 mg of enoxaparin, 20 mg of enoxaparin, or placebo, given subcutaneously once a day for 6-14 days. The primary outcome was venous thromboembolism (deep-vein thrombosis or pulmonary embolism) between days 1 and 14. At the 40-mg dose, the risk of venous thromboembolism was significantly reduced in patients with heart failure, as well as in patients with other medical illnesses, including respiratory failure, infectious disease, or rheumatic disorders. The incidence of venous thromboembolism was 5.5% in the group that received 40 mg of enoxaparin as compared with 14.9% in the group that received placebo (p <0.001), a benefit that was maintained at 3-month follow-up. There was no significant difference in the incidence of venous thromboembolism between the group that received 20 mg of enoxaparin (15%) and the placebo group. Adverse effects did not significantly differ between the placebo group and either enoxaparin group. This study clearly establishes an effective strategy for lowering the risk of venous thromboembolism in the acutely ill population and provides a framework for future trials in this area.