Cost-Effectiveness of Varying Weight Loss Interventions: Elena Losina, PhD

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The glucagon peptide-1 receptor agonist (GLP-1 RA) tirzepatide was found to be more cost-effective than semaglutide when treating patients with knee osteoarthritis and obesity, reported a recent study published in the Annals of Internal Medicine. 1

Anti-obesity medications have been shown to provide substantial pain relief for patients with obesity and knee osteoarthritis. The weight loss helped relieve patients of pain, slowed cartilage loss in those with knee osteoarthritis, and may have also had anti-inflammatory and immunomodulatory benefits.2 However, GLP-1 RA usage is often long-term, and over time the cumulative costs have the potential to outweigh health benefits, thus disproportionately affecting marginalized communities. The study assessed the cost-effectiveness based on a lifetime quality-adjusted life-year (QALY) threshold that quantifies the number of life years gained and the health-related quality of life based on a health intervention like GLP-1 RAs. The cost-effectiveness threshold is a predefined value that determines whether a health care intervention is good value for its cost, represented by the amount a payer (ie, insurers or government programs such as Medicaid and Medicare) is willing to pay per QALY.

For a health care intervention to be considered cost-effective, the incremental cost-effectiveness ratio (ICER) (ie, the additional cost divided by the additional health benefit) must be below a certain threshold. A commonly accepted threshold among payers for cost-effectiveness is $100,000 per QALY.

Nonpharmacologic interventions like diet and exercise had a lower QALY, ranging from $25,400 to $57,400, which indicates they provide good value even in a setting with limited health care benefits. Other weight loss interventions like tirzepatide and bariatric surgery had higher thresholds at $57,400 and $30,700, respectively, meaning they are considered worthwhile investments since health care systems are more willing to allocate larger sums per QALY gained.

The American Journal of Managed Care® spoke with corresponding author Elena Losina, PhD, codirector of the Orthopedics and Arthritis Center for Outcomes Research at Brigham and Women’s Hospital, about paired QALYs of GLP-1 RAs and diet and exercise, GLP-1 RAs and bariatric surgery, or just bariatric surgery.

“In the United States, there is no commonly accepted willingness-to-pay or cost-effectiveness ratio. So, different payers have different cost-effectiveness thresholds,” Losina said. “So, for payers with low-cost effectiveness thresholds, diet and exercise may be the preferred strategy. For payers with higher cost-effectiveness thresholds, then tirzepatide may be a better option in terms of providing more clinical benefits without exceeding the cost-effectiveness threshold.”

While tirzepatide was seen to be more cost-effective than semaglutide, bariatric surgery, which includes gastric bypass and laparoscopy, showed a significantly lower ICER of $20,600 per QALY.

“You put the cost upfront for bariatric surgery, and patients experience benefits for a long period of time,” Losina said. “Comparing those 2 strategies, then, bariatric surgery shows that it provides better benefit without exceeding the cost-effectiveness threshold. That's why it is shown to be a cost-effective option for those patients who are eligible and willing.”

This study highlights the complex balance between clinical benefit and cost when considering GLP-1 RA therapies for obesity and knee osteoarthritis. Although tirzepatide was more cost-effective than semaglutide, bariatric surgery offered even greater long-term value below commonly accepted thresholds. Ultimately, treatment decisions may depend on payer willingness-to-pay benchmarks and patient eligibility, underscoring the need for individualized approaches that align clinical outcomes, economic realities, and equitable access to care.

References

1. Betensky DJ, Smith KC, Katz JN, et al. The cost-effectiveness of semaglutide and tirzepatide for patients with knee osteoarthritis and obesity. Ann Intern Med. Published online September 16, 2025. doi:10.7326/ANNALS-24-03609

2. Anderer S. Semaglutide eases knee osteoarthritis pain in people with obesity. JAMA. 2025;333(1):12. doi:10.1001/jama.2024.24260