Cost-effectiveness of low-molecular weight heparin and unfractionated heparin in treatment of deep vein thrombosis

Background: Acute deep vein thrombosis has traditionally been treated with unfractionated heparin (UFH), administered intravenously, but low-molecular-weight heparins (LMWH), administered subcutaneously, have recently become available. The authors sought to determine which therapy was more cost-effective for inpatient and outpatient treatment of deep vein thrombosis. Methods: An incremental cost-effectiveness analysis based on a decision tree was performed for 4 treatment strategies for deep vein thrombosis. Rate of major hemorrhage while receiving heparin, rate of recurrence of venous thromboembolism 3 months after treatment and mortality rate 3 months after treatment were determined by meta-analysis. Costs for the UFH therapy were prospectively collected by a case-costing accounting system for 105 patients with deep vein thrombosis treated in fiscal year 1995/96. The costs for LMWH therapy were modelled, and cost-effectiveness was determined by decision analysis. Results: Meta-analysis revealed a mean difference in risk of hemorrhage of -1.1% (95% confidence interval [Cl] -2.4% to 0.3%), a mean difference in risk of recurrence of venous thromboembolism of -2.6% (95% Cl -4.5% to -0.7%) and a mean difference in risk of death of -1.9% (95% Cl -3.6% to -0.4%), all in favour of subcutaneous unmonitored administration of LMWH. The cost to treat one inpatient was $2993 for LMWH and $3048 for UFH. Even more would be saved if LMWH was delivered on an outpatient basis (cost of $1641 per patient). The cost-effectiveness analysis showed that LMWH in any treatment setting is more cost effective than UFH. A sensitivity analysis demonstrated the robustness of this conclusion. Interpretation: Treatment of deep vein thrombosis with LMWH is more cost effective than treatment with UFH in both inpatient and outpatient settings.