Abstract:
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.