Low-molecular-weight heparin versus unfractionated heparin for prophylaxis of venous thromboembolism in medicine patients--a pharmacoeconomic analysis.

BACKGROUND: Prevention of in-hospital venous thromboembolism (VTE) is identified internationally as a priority to improve patient safety. Advocated alternatives include low-dose unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). Although LMWHs are as effective as UFH, less frequent administration and potentially safer adverse effect profile associated with LMWHs might off-set greater drug acquisition costs. The objective of this study was to determine the most cost-effective thromboprophylaxis strategy for hospitalized medicine patients and specific subgroups in Canada.

METHODS: A decision-analytic model assessed costs and outcomes of LMWH compared to UFH for thromboprophylaxis in at-risk hospitalized medicine patients from an institutional perspective. The outcome of interest was the incremental cost-effectiveness ratio (ICER) for preventing deep vein thrombosis (DVT) and combined untoward events (pulmonary embolism [PE], major bleed, and death). The time horizon of the model was the hospital stay.

RESULTS: In the base-case analysis, LMWH thromboprophylaxis resulted in higher costs ($7.40), but 3.6 and 1.1 fewer DVT and untoward events per 1000 patients, respectively, with associated ICERs of $2042 and $6832. Results remained predominantly stable when alternative assumptions were evaluated in the sensitivity analysis. Low-molecular-weight heparin had the most favorable economic profile in patients with a history of DVT. In the probabilistic sensitivity analysis, in 33% of simulations LMWH was less costly and more effective, whereas the reverse was true for UFH only in 13% of simulations.

CONCLUSIONS: Low-molecular-weight heparin administration is a cost-effective alternative for thromboprophylaxis strategy in Canadian hospitalized medicine patients.