Introduction: Extended duration anticoagulation with rivaroxaban for an additional 6-12 months can reduce recurrent venous thromboembolic events (VTE) compared to placebo by ~82%, but at the detriment of increased bleeding. We sought to estimate the cost-effectiveness of extended duration prophylaxis of recurrent VTE with rivaroxaban.
Material and methods: A Markov model was developed to estimate the cost-effectiveness of extended duration rivaroxaban, 20mg daily, compared to placebo using a Medicare perspective, a one-monthcycle length and a 40-year time horizon. The model assumed a cohort of 58-year-old patients who had already completed an initial 6-12 months of anticoagulation with rivaroxaban or a vitamin K antagonist; and whom prescribers had clinical equipoise with respect to the need for continued anticoagulation. Data sources included EINSTEIN-Extension and other published studies of VTE. Outcomes included direct treatment costs (in 2013US$), quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs).
Results: Extended duration rivaroxaban resulted in higher treatment costs ($22,645 vs. $22,083) but yielded greater QALYs (16.167 vs. 16.134) as compared to placebo; corresponding to an ICER of $17,030/QALY gained. Our model was most sensitive to the baseline risk of bleeding and recurrent VTE, the hazard ratio of developing a recurrent event while on rivaroxaban and time horizon. Monte Carlo Simulation suggested rivaroxaban would be cost-effective in 66% of 10,000 iterations, assuming a willingness-to-pay threshold of $50,000/QALY.
Conclusion: Despite the cost of rivaroxaban and an increased risk of bleeding, extending VTE treatment for an additional 6-12 months with rivaroxaban was found cost-effective compared to the placebo over a 40-year time horizon.
Keywords: Anticoagulation; Cost-effectiveness analysis; Extended treatment; Markov model; Rivaroxaban; Venous thromboembolism.
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