Cost effectiveness of dalteparin for preventing venous thromboembolism in abdominal surgery

Introduction: Patients undergoing abdominal surgeries face substantial risk of experiencing venous thromboembolic events in the perioperative period. The low-molecular-weight heparin dalteparin sodium is clinically effective in reducing the incidence of venous thromboembolism (VTE) in these patients. Dalteparin may be used in low (2500 units [U]) and high (5000U) once-daily doses for this indication. However, the cost effectiveness of dalteparin 5000U compared with dalteparin 2500U and unfractionated heparin (UFH) for this indication has not been studied. Objective: To conduct a cost-utility analysis to evaluate the cost effectiveness of dalteparin compared with UFH for preventing VTE in patients undergoing elective abdominal surgery. Methods: A Markov model, from a healthcare perspective, was constructed to evaluate the cost effectiveness of dalteparin 5000U and dalteparin 2500U compared with UFH. A 69-year-old mixed sex patient population was studied using pooled probabilities of clinical outcomes from randomised, controlled trials. Cost data were mostly derived from Medicare reimbursement, in year 2002-03 values. Cost effectiveness was measured as cost per QALY gained over the patient's lifetime. Results: Total costs for patients given UFH, dalteparin 2500U and dalteparin 5000U were $US45_855, $US45_882 and $US46_308, respectively, while QALYs were 9.5603, 9.5632 and 9.5811, respectively. Hence, the incremental cost effectiveness of dalteparin 5000U over dalteparin 2500U and UFH was $US23_799/QALY and $US21_779/QALY gained, respectively. Similarly, cost effectiveness for dalteparin 2500U over UFH was $US9310/QALY gained. Univariate sensitivity analysis showed that dalteparin 5000U maintained its cost effectiveness (incremental cost-effectiveness ratio [ICER] =90% patients receive the benefit of the medication, policy makers would need to commit substantially more resources than suggested by the baseline ICERs.