Summary
This study aimed to evaluate the cost-effectiveness of prophylaxis with rivaroxaban
vs. enoxaparin in the prevention of venous thromboembolism (VTE) after total hip replacement
(THR) and total knee replacement (TKR) from the perspective of the Canadian healthcare
system. A model was developed that included both acute VTE (represented as a decision
tree) and long-term complications (represented as a Markov process with one-year cycles).
Transition probabilities were derived from phase III clinical trials comparing rivaroxaban
with enoxaparin and published literature. Costs were derived from the Ontario Case
Costing Initiative and publicly available sources. Utilities were derived from published
literature. The model reported VTE event rates, quality-adjusted life expectancy and
direct medical costs over a five-year horizon. Costs are reported in 2007 Canadian
Dollars (C$). When rivaroxaban and enoxaparin are compared in patients undergoing
THR, rivaroxaban dominates enoxaparin. That is, rivaroxaban is associated with improved
health outcomes as measured by increased quality-adjusted life years (QALYs; 0.0006)
and fewer symptomatic VTE events (0.0061), and also with lower cost (savings of C$300)
per patient. Similarly, rivaroxaban dominates enoxaparin in patients undergoing TKR,
achieving a gain of 0.0018 QALYs, a reduction of 0.0192 symptomatic venous thromboembolic
events and savings of C$129 per patient. Rivaroxaban is a cost-effective alternative
to enoxaparin for VTE prophylaxis in patients undergoing THR and TKR. Over a five-year
horizon, rivaroxaban dominated enoxaparin in the prevention of VTE events in patients
undergoing THR and TKR, providing more quality-of-life benefit at a lower cost.
Keywords
Anticoagulants - surgery - thrombosis