The development of low-molecular-weight (LMW) heparin has provided physicians with the opportunity to treat deep venous thrombosis (DVT) on an outpatient basis. This ability is important because there are more than 200,000 first lifetime cases of venous thrombosis and 100,000 to 200,000 deaths from pulmonary embolism per year in the United States. Previously, standard treatment of DVT included the intravenous administration of unfractionated heparin for five to seven days on an inpatient basis. A Canadian study found that LMW heparin (enoxaparin) was safe and effective when used to treat DVT on an out-patient basis, compared with unfractionated heparin. The study also demonstrated cost reduction in the group treated with LMW heparin. Spyropoulos and colleagues studied the safety, efficacy, and cost reduction of LMW heparin versus unfractionated heparin in a managed care setting in the United States.

The study design was a retrospective analysis of medical and administrative records of health plan members who were diagnosed with DVT. To be included in the study, participants had to meet the same inclusion and exclusion criteria of the Canadian study. Persons with DVT diagnosis were treated with unfractionated heparin in the hospital setting for the first portion of the study. These records were compared with those of patients treated in the latter part of the study, who received LMW heparin. In each group, warfarin therapy was initiated for long-term treatment of DVT.

Clinical data obtained were death from thromboembolic causes, recurrent DVT or pulmonary emboli, and major bleeding episodes. Minor clinical data obtained included minor bleeding episodes while taking heparin or warfarin, and heparin-induced thrombocytopenia. Administrative information gathered included demographics, medical services, and prescription drugs.

There was no statistical difference between the LMW heparin group and those treated with unfractionated heparin with regard to recurrent thromboembolic events or bleeding events. There was no recurrent pulmonary emboli or major bleeding in the warfarin phase in either of the groups. There was only one episode of major bleeding, which occurred in the LMW heparin group. The aver-age cost savings in the LMW heparin group was $2,583 per patient.

The authors conclude that the treatment of acute proximal DVT with LMW heparin in a primary outpatient setting is safe and effective. In addition, the use of this type of heparin can lead to reduction in cost of treatment by eliminating or reducing the number of inpatient stays.