In the double-blind placebo-controlled study, Dr. Meyer Samama of the Hotel Dieu in Paris, France, and colleagues randomly assigned 1102 hospitalized patients into one of three treatment groups: 40 mg of enoxaparin, 20 mg of enoxaparin or placebo. The patients, who received subcutaneous injections once daily for six to 14 days, were over the age of 40 and had either congestive heart failure, acute respiratory failure or some other condition that put them at risk for developing venous thromboembolism.

From hospital days 1 to 14, venous thromboembolism occurred in only 5.5% of the group that received 40 mg enoxaparin, significantly less than the 15% in the 20-mg group and 14.9% in the placebo group. The difference was maintained in the 40-mg group at a 3-month follow-up. No differences in adverse events were observed among the three groups.

The authors also point out that "[o]ur trial, which was not designed to investigate differences in mortality, revealed a clinically relevant trend, with a 2.5% absolute reduction in the overall risk of death at three months in the group assigned to 40 mg of enoxaparin."

"[D]aily injections of 40 mg of enoxaparin," the researchers conclude, "significantly reduced the incidence of venous thromboembolism in acutely ill medical patients during hospitalization without increasing the risk of major hemorrhage."

N Engl J Med 1999;341:793-800.