Cost-effectiveness of prolonged thromboprophylaxis after cancer surgery

Background: Consensus guidelines recommend prolonged thromboprophylaxis for up to 4 weeks after major abdominopelvic cancer operations. Several factors impede widespread adoption of these guidelines. These include lack of awareness, cost, increased bleeding complications, increased incidence of heparin-induced thrombocytopenia, and poor patient compliance. Methods: A cost-effectiveness model was constructed comparing four potential strategies to postdischarge thromboprophylaxis in surgical oncology patients: (1) low-molecular-weight heparin (LMWH) once daily; (2) low-dose unfractionated heparin (LDUH) three times daily; (3) oral aspirin once daily; or (4) no prolonged prophylaxis. Probabilities and costs were estimated on the basis of published literature and average Medicare reimbursement. The decision analysis was conducted from the perspective of the health care system, with the primary end point being cost per patient without venous thromboembolism (VTE). Sensitivity analyses tested the robustness of the results. Results: LDUH was most cost-effective, saving $154 per patient without VTE compared with no prophylaxis. LMWH was not cost-effective, incurring a cost of $230 per patient without VTE compared with no prophylaxis. Aspirin was a viable alternative to LDUH, saving $123 compared with no prophylaxis. When poor compliance was considered, aspirin became the dominant strategy. Sensitivity analyses failed to show any instance where LMWH was cost-effective. In terms of population costs, widespread use of LDUH after discharge would save $30.3 million per year in the United States. Conclusions: Although all chemical prophylaxis is effective in preventing VTE in the outpatient setting after cancer surgery, either LDUH or aspirin are the most cost-effective, depending on patient compliance.