Adults with obesity have more choices than ever before of therapies that reduce body mass index (BMI) and consequently improve related chronic health conditions. Bariatric procedures are among the most well-studied options with the longest follow-up. Despite achieving the greatest reductions in BMI and rates of diabetes remission, uptake of bariatric surgery remains low. Endoscopic sleeve gastroplasty (ESG), a minimally invasive approach that avoids any skin incisions, reduced BMI and improved metabolic health conditions compared with lifestyle intervention (LI) in one randomised trial, and the first devices for ESG were authorised by the US Food and Drug Administration (FDA) in 2022. However, evidence of the long-term effectiveness of ESG is limited, and the procedure is not yet covered by most health insurance plans.

Glucagon-like peptide (GLP-1) agonists, initially approved for diabetes and used off-label to treat obesity, have been shown to achieve substantial weight loss and improvement in cardiovascular health. Two of these agents—liraglutide and semaglutide—and the dual incretin agonist tirzepatide are now approved for obesity treatment, and demand appears to be high. However, many questions remain about the long-term effectiveness and side effects of GLP-1 agonists for treating obesity, and they have entered the US market at list prices approaching or exceeding US$1000 per month.

At an individual level, patients seeking obesity treatment may consider multiple options and make a decision based on personal preference for various attributes of the method, including the trade-off between expected benefits and harms. At a population level, when numerous options are available to manage a given condition, decision-makers are justified in questioning the value that each option provides in relation to its cost. Economic evaluation in general, and cost-effectiveness analysis specifically, are tools for answering these questions. Cost-effectiveness analysis provides an estimate of what we get—in terms of health benefit—for what we spend …