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 1,000 patients) at 3 months for patients undergoing major orthopaedic surgery compared with enoxaparin. The cost savings (per patient) of using fondaparinux over enoxaparin are US 61 dollars at 30 days, US 89 dollars at 3 months, and US 155 dollars at 5 years. In the label-based analysis, fondaparinux was estimated to prevent 17.8 venous thromboembolic events (per 1,000 patients) at 3 months compared with enoxaparin, producing savings per patient of US 25 dollars at discharge, US 112 dollars over 1 month, US 141 dollars over 3 months and US 234 dollars 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.