Economic analysis of low-dose heparin vs the low-molecular-weight heparin enoxaparin for prevention of venous thromboembolism after colorectal surgery

Background: Low-dose heparin and low-molecular-weight heparin are effective strategies for preventing venous thromboembolism in colorectal surgery. Th e economic attractiveness of these 2 strategies in North America is unknown . We conducted an economic analysis of low-dose heparin calcium compared wi th enoxaparin sodium, a low-molecular-weight heparin, for thromboembolism p rophylaxis after colorectal surgery. Methods: We used decision analysis, with an economic perspective of a third -party payer. Efficacy data were obtained from the Canadian Multicentre Col orectal Deep Vein Thrombosis Prophylaxis Trial and a literature review. Can adian costs for diagnosis and treatment of deep vein thrombosis (DVT), pulm onary embolism (PE), and major bleeding were obtained from chart review and a national hospital database of colorectal surgery, American costs were ob tained from published literature. The main outcomes were incremental benefi ts (symptomatic DVTs, symptomatic PEs, and major bleeding events avoided) a nd incremental costs for every 1000 patients treated. Results: In the Canadian Colorectal Trial, the relative risk of DVT and PE for enoxaparin compared with low-dose heparin was 1.0 (95% confidence inter val, 0.7-1.5), and the relative risk of major bleeding was 1.8 (95% confide nce interval, 0.8-3.9). With the use of these data in the baseline analysis , a strategy of enoxaparin prophylaxis was associated with equal numbers of symptomatic DVTs and PEs, and an excess of 12 major bleeding episodes for every 1000 patients treated, with an additional cost of $86 050 (Canadian d ata) or $145 667 (US data). In a sensitivity analysis using optimal assumpt ions for efficacy and safety of enoxaparin (relative risk of DVT, 0.8; rela tive risk of PE, 0.4; relative risk of major bleeding, 1.0), a strategy of enoxaparin prophylaxis was associated with 0.8 fewer symptomatic DVT, 3 few er symptomatic PEs, and equal numbers of major bleeding episodes for every 1000 patients treated, with an additional cost of $15 217 (Canadian data) o r $107 614 (US data). Conclusion: Although heparin and enoxaparin are equally effective, low-dose heparin is a more economically attractive choice for thromboembolism proph ylaxis after colorectal surgery.