A Cost-Effectiveness Analysis of Rivaroxaban Compared to Warfarin for the Management of Venous Thromboembolism in Western Kenya.

BACKGROUND AND

OBJECTIVE

Access to direct oral anticoagulants (DOACs) in sub-Saharan Africa is limited due to prohibitive upfront costs, making warfarin the standard of care for many patients, especially those relying on public-sector healthcare. This study evaluated the cost-effectiveness of using the DOAC, rivaroxaban, compared to warfarin for treating venous thromboembolism (VTE), a cardiovascular disorder caused by blood clots in the veins, in western Kenya.

METHODS

We developed a discrete-time individual state-transition Markov model to simulate a VTE patient's quality-adjusted life-years (QALYs) and annual treatment costs under a rivaroxaban or warfarin therapy strategy. Transition state probabilities were derived from real-world event-rate data observed in patients treated with rivaroxaban (n = 160) or warfarin (n = 116) for VTE at Moi Teaching and Referral Hospital in western Kenya. Base-case parameter values were obtained from cohort event rates, local costs, and literature-derived utility values. Cost-effectiveness was assessed over a 1-year time horizon using an incremental cost-effectiveness ratio (ICER) threshold of (US)$6020.40 per QALY gained (equivalent to three times Kenya's 2021 per capita GDP). Deterministic and probabilistic sensitivity analyses were conducted to assess parameter and model uncertainty.

RESULTS

After 12 months, total mean treatment costs per patient were $216.00 and $173.00 using warfarin and rivaroxaban, respectively. In the base-case analysis, rivaroxaban therapy resulted in an additional 0.023 QALYs per patient compared to warfarin, with an ICER of $- 1862.00 per QALY gained. Based on probabilistic sensitivity analysis with Monte Carlo simulation, when costs, utility values, and event rates were varied, rivaroxaban was cost-effective compared to warfarin in 84.1% of all simulations at a willingness-to-pay threshold of $6020.40 per QALY. One-way sensitivity analyses and scenario analyses were stable with rivaroxaban therapy, resulting in fewer costs and higher QALYs.

CONCLUSIONS

In this study, rivaroxaban is a clinically and economically superior alternative to warfarin. This research may catalyze further discussions with policymakers and industry partners to scale up the appropriate use of rivaroxaban in resource-constrained settings.