Economic evaluations of antiobesity medications: A systematic literature review

The global prevalence of obesity is rising rapidly. With several antiobesity medications approved and many more in development, understanding their economic value is increasingly important. This study reviews full economic evaluations of approved antiobesity medications to assess cost-effectiveness and inform reimbursement and access decisions. We systematically reviewed full economic evaluations of approved antiobesity medications in adults with overweight or obesity, including tirzepatide, semaglutide, liraglutide, naltrexone/bupropion, orlistat, phentermine and phentermine/topiramate. Ovid MEDLINE, Embase and government websites were searched for studies comparing these medications with standard care or with each other. Methodological quality was assessed using the BMJ checklist and reporting quality using CHEERS 2022. A narrative synthesis was performed, focusing on quality-adjusted life years and incremental cost-effectiveness ratios. The review followed PRISMA guidelines and was registered on PROSPERO (CRD420251139475). Twenty-six studies met inclusion criteria. All were conducted in high or upper-middle-income countries, predominantly from payer perspectives. Results were heterogeneous and sensitive to model assumptions; however, consistent trends emerged. Semaglutide demonstrated variable cost-effectiveness but consistently outperformed liraglutide, which was generally not cost-effective. Tirzepatide produced greater health gains and frequently favourable ICERs, though it often exceeded willingness-to-pay (WTP) thresholds in lower-threshold settings. Among older agents, phentermine/topiramate appeared economically competitive, largely due to lower acquisition costs. The cost-effectiveness of antiobesity medications is highly context-dependent. Semaglutide is generally more cost-effective than liraglutide, while tirzepatide offers greater clinical benefit but may exceed WTP thresholds. Direct comparative economic evidence between newer agents remains limited. Long-term real-world data and clearer distinctions between cost-effectiveness and affordability are needed to inform policy decisions.