Objectives: A cost-effectiveness model for rivaroxaban evaluated the cost-effectiveness of prophylaxis with rivaroxaban (a once-daily, orally administered Factor Xa inhibitor) vs enoxaparin in the prevention of venous thromboembolism (VTE) after total hip replacement (THR) and total knee replacement (TKR). This Canadian analysis was conducted using the Ontario Ministry of Health perspective over a 5-year time horizon. The model combined clinical data and builds upon existing economic models.
Methods: The model included both acute VTE (represented as a decision tree) and long-term complications (represented as a Markov process with 1-year cycles) phases. The model allowed VTE event rates, quality-adjusted life expectancy and direct medical costs to be estimated over a 5-year time horizon, based on current approved practice patterns in Canada. A number of one-way sensitivity analyses were performed on the baseline assumptions, including a comparison of rivaroxaban with dalteparin, and probabilistic sensitivity analyses were performed to address any uncertainty concerning model inputs.
Results: When comparing equal durations of therapy, rivaroxaban dominated enoxaparin in the prevention of VTE events in patients undergoing THR and TKR, providing more benefit at a lower cost. Rivaroxaban was cost-effective when comparing 35 days' prophylaxis with 14 days' prophylaxis with enoxaparin following THR. One-way and probabilistic sensitivity analyses demonstrated that the results of the economic analysis were robust to variations in key inputs. Rivaroxaban remained dominant during one-way sensitivity analyses comparing rivaroxaban with dalteparin after THR or TKR.
Limitations: Although clinical trial data were used in the prophylaxis module, assumptions and values used in the post-prophylaxis and long-term complication (LTC) modules were based on several different literature sources; it was not always possible to source Canadian data.
Conclusions: This economic analysis suggests that the use of rivaroxaban for the prophylaxis of VTE after THR or TKR in Canada was cost-effective.