The Cost-Effectiveness of Enoxaparin Compared with Aspirin for Thromboprophylaxis in Patients with Orthopaedic Trauma.

Abstract

Although clinical guidelines endorse enoxaparin for the prevention of venous thromboembolism in patients with orthopaedic trauma, recent evidence from a large clinical trial has demonstrated that aspirin provides comparable protection against death and pulmonary embolism. This study evaluated the cost-effectiveness of thromboprophylaxis with enoxaparin compared with that with aspirin in patients with orthopaedic trauma from the perspective of the U.S. health-care system. The study modeled a hypothetical cohort of adult patients with an operatively treated extremity, pelvic, or acetabular fracture based on data from a recent clinical trial and national databases. We used a decision analysis model to compare 30 mg of enoxaparin with 81 mg of aspirin, administered twice daily in-hospital and prescribed for 21 days after discharge. Health-care costs and quality-adjusted life-years (QALYs) within 1 year after the injury derived from published research and publicly available cost data were based on potential disease states, including death or a combination of pulmonary embolism, proximal deep vein thrombosis, distal deep vein thrombosis, or a bleeding complication. We assessed cost-effectiveness compared with a willingness-to-pay threshold of $150,000 per QALY. Our model estimated that the 1-year health-care costs among patients prescribed enoxaparin were $35,301, producing 0.6705 QALYs. Aspirin was associated with $35,067 in 1-year health-care costs and 0.6701 QALYs. The overall health-care costs were $234 higher with enoxaparin but yielded only a 0.0004 improvement in QALYs, for an incremental cost-effectiveness ratio for enoxaparin of $635,340 per QALY, indicating that enoxaparin is not cost-effective compared with aspirin. In a sensitivity analysis, the probability of enoxaparin thromboprophylaxis being cost-effective compared with aspirin was 9.8% in 10,000 iterations. The findings suggest that enoxaparin is not cost-effective relative to aspirin for thromboprophylaxis in patients with orthopaedic trauma. The results support consideration of aspirin as a preferred agent in future guidelines, especially given the consistent patient preference for its oral administration. Economic and Decision Analysis Level I. See Instructions for Authors for a complete description of levels of evidence.