Cost utility of substituting enoxaparin for unfractionated heparin for prophylaxis of venous thrombosis in the hospitalized medical patient.

BACKGROUND Both heparin and enoxaparin are effective for the prevention of venous thromboembolism (VTE) in medical patients. On the basis of price, heparin appears preferable because it is less expensive. However, choosing enoxaparin may have greater cost utility when the outcomes of heparin-induced thrombocytopenia (HIT) and heparin-induced thrombocytopenia with thrombosis (HITT) are considered. OBJECTIVE To determine the cost utility of substituting enoxaparin for heparin from payer and institutional perspectives. DESIGN A decision analysis model was used. Cost data were based on Medicare reimbursement and the medication and laboratory costs for a multi-institutional healthcare system. Quality-adjusted life years (QALYs) saved by preventing HIT/HITT through the use of enoxaparin were based on published data. Costs are expressed on a per-day basis, and the incremental cost of enoxaparin over that of heparin was used in the calculation of cost/QALY. A sensitivity analysis also was performed. SETTING Inpatient medicine. PATIENTS All medical patients for whom VTE prophylaxis was appropriate. INTERVENTIONS Substitution of enoxaparin for heparin. MEASUREMENT Cost/QALY. RESULTS From a payer perspective, using enoxaparin resulted in a decrease in cost of 28.61 dollars over that of heparin and saved 0.00629 QALYs in the base case, resulting in a savings of 4550.17 dollars/QALY. The sensitivity analysis showed this finding of decreased cost and increased effectiveness to be consistent. From an institutional perspective, the use of heparin generally appeared less costly but was dependent on medication price, length of stay required, and bed utilization. CONCLUSIONS From a payer and, by extrapolation, a societal perspective, cost-utility analysis supports the use of enoxaparin in place of heparin for the prevention of VTE in medical inpatients. From an institutional perspective, the decision is more complicated, but in most cases, the use of enoxaparin also is supported.