Cost effectiveness of thromboprophylaxis with a low-molecular-weight heparin versus unfractionated heparin in acutely ill medical inpatients.

OBJECTIVE To compare the cost effectiveness of prophylaxis with a low-molecular-weight heparin with that of prophylaxis with unfractionated heparin for the prevention of venous thromboembolism in acutely ill medical inpatients. STUDY DESIGN Cost-effectiveness analysis based on decision-tree model. PARTICIPANTS AND METHODS A hypothetical cohort of 10 000 patients was assumed to receive either (1) prophylaxis with enoxaparin, a low-molecular-weight heparin, 40 mg daily; (2) prophylaxis with unfractionated heparin, 5000 IU twice daily; or (3) no prophylaxis. We developed a decision-analytic model with parameter estimates derived from published clinical trials and other secondary sources. Then, for each strategy, we estimated the risks of venous thromboembolism, complications of prophylaxis and treatment (heparin-induced thrombocytopenia and bleeding), mortality, and costs of prophylaxis and treatment within a 30-day period. RESULTS In a hypothetical cohort of 10 000 inpatients, expected numbers of deaths attributable to venous thromboembolism or drug complications related to both prophylaxis for and treatment of VTE over a 30-day period were 37 with enoxaparin prophylaxis, 53 with unfractionated heparin prophylaxis, and 81 with no prophylaxis. In 2001, corresponding expected costs of prevention, diagnosis, and management of VTE were $3 502 000 for enoxaparin, $3 772 000 for unfractionated heparin, and $3 105 000 for no prophylaxis. The incremental cost per death averted with enoxaparin prophylaxis versus no prophylaxis was $9100. Enoxaparin dominated unfractionated heparin by being both more effective and less costly in the base-case analysis, as well as in sensitivity analyses in which equal efficacy and equal risks of bleeding were assumed. CONCLUSIONS Thromboprophylaxis with this low-molecular-weight heparin represents a cost-effective use of healthcare resources in acutely ill medical inpatients and dominates thromboprophylaxis with unfractionated heparin.