A Cost-Effectiveness Analysis of Fondaparinux Sodium Compared with Enoxaparin Sodium as Prophylaxis Against Venous Thromboembolism: Use in Patients Undergoing Major Orthopaedic Surgery

Objective: To determine the cost effectiveness of fondaparinux sodium compared with enoxaparin sodium for prophylaxis against venous thromboembolism in patients undergoing major orthopaedic surgery. Methods: Using a cohort simulation model, two primary analyses were conducted from the perspective of the US healthcare payer. Probabilities for a trial-based analysis were obtained from patients participating in the fondaparinux clinical trial programme supplemented with data from published literature. Probabilities for a label-based analysis were estimated for a hypothetical cohort of US patients receiving either fondaparinux or enoxaparin as recommended by US FDA-approved labelling. Resource use and costs were obtained from large US healthcare databases. Outcome measures were rates of symptomatic thromboembolic events and healthcare costs. Costs were in 2003 values. Results: In the trial-based analysis, fondaparinux was estimated to prevent 15.1 symptomatic venous thromboembolic events (per 1000 patients) at 3 months for patients undergoing major orthopaedic surgery compared with enoxaparin. The cost savings (per patient) of using fondaparinux over enoxaparin are $US61 at 30 days, $US89 at 3 months, and $US155 at 5 years. In the label-based analysis, fondaparinux was estimated to prevent 17.8 venous thromboembolic events (per 1000 patients) at 3 months compared with enoxaparin, producing savings per patient of $US25 at discharge, $US112 over 1 month, $US141 over 3 months and $US234 over 5 years. Results remain robust to clinically plausible variation in input parameters and assumptions. Conclusion: Our model suggests that fondaparinux, when compared with the current standard regimen of enoxaparin for prophylaxis of venous thromboembolism in major orthopaedic surgery, improves outcomes and is cost saving from a US healthcare-payer perspective over the broad range of assumptions evaluated.