Abstract
BACKGROUND: Baloxavir marboxil, an antiviral used only in private hospitals in Hong Kong since February 2019 for treating influenza, is recognized for its efficacy against strains resistant to standard antiviral agents, providing an alternative to neuraminidase inhibitors such as oseltamivir. METHODS: This study compares the cost-effectiveness of baloxavir and oseltamivir for influenza treatment in otherwise healthy (OwH) and high-risk (HR) adult outpatients in Hong Kong from the healthcare-payer's perspective. A decision tree was utilized to study the progression of influenza and estimate associated costs and quality-adjusted life-years (QALYs) over 14 days for each antiviral. FINDINGS: In the general population, the incremental cost-effectiveness ratio (ICER) for baloxavir is $89,921 per QALY. Compared to oseltamivir, baloxavir shows a QALY gain with an incremental cost of $13,626 per QALY, below the $152,667 willingness-to-pay (WTP) threshold. At this WTP level, there is a 92% chance the additional cost of baloxavir is accepted. As oseltamivir resistance rises, its economic benefit decreases, while baloxavir's improves. In the OwH population, baloxavir's ICER is $145,316 compared to baseline and $115,811 compared to oseltamivir, with a 49% probability of baloxavir being cost-effective. In the HR population, baloxavir dominates, with ICERs of $36,163 and $-15,072, and a 99% probability of cost-effectiveness. CONCLUSION: As a result, baloxavir could potentially be considered as the influenza agent of choice over oseltamivir in Hong Kong, despite a higher acquisition cost. Therefore, we recommended that integrating baloxavir into the Hospital Authority Drug Formulary in Hong Kong could enhance healthcare resource allocation and improve patient outcomes.