Significant Care Costs for Obesity Medications Associated With High Rates of Treatment Discontinuation

Key Takeaways:

• In a study comparing newer obesity medications against the older drug phentermine, the newer medications accumulated higher drug costs 3 years after initiation, with liraglutide having the highest prescription costs.
• All 4 cohorts demonstrated low treatment durations after initiation, showcasing how high drug costs negatively impact treatment adherence.
• Rates of health care utilization were similar across cohorts, although phentermine users had a greater increase in primary care visits.

Ever since the US Food and Drug Administration (FDA) approved semaglutide and tirzepatide for the treatment of obesity, prescriptions of obesity medications have increased. However, high drug costs and lack of coverage lead patients to discontinue treatment within 1 year. Not only is coverage for newer obesity medications limited, but many payers require patients to initiate treatment with older, less expensive therapies.

Using data taken from the Merative MarketScan claims database between 2012 and 2023, researchers compared care costs and health care utilization across 4 different types of obesity medications: phentermine, phentermine-topiramate-extended release (ER), naltrexone-bupropion-sustained release (SR), and liraglutide.

The study identified 136 788 patients receiving phentermine, 13 888 phentermine-topiramate-ER users, 28 712 individuals being treated with naltrexone-bupropion-SR, and 49 266 patients using liraglutide.

Continuous treatment durations were low across cohorts. After initiation, phentermine users averaged 4.4 months; naltrexone-bupropion-SR users averaged 5.4 months; phentermine-topiramate-ER users averaged 6.5 months; liraglutide users averaged 6.7 months.

Pharmacy and Care Costs

Three years after medication initiation, drug costs were higher for phentermine-topiramate-ER, naltrexone-bupropion-SR, and liraglutide compared to phentermine. Liraglutide had the highest increase, with an estimated $8263 rise in drug costs in year 1.

In on-treatment models, the cost of a 30-day supply of each medication was $12.67 for phentermine, $214.26 for phentermine-topiramate-ER, $265.38 for naltrexone-bupropion-SR, and $1259.78 for liraglutide.

Phentermine was associated with lower total care costs than the other cohorts. Similar to pharmacy costs, patients using liraglutide accumulated the greatest increases in care costs.

Health Care Utilization

Although all cohorts experienced an increase in primary care visits after treatment initiation, newer obesity medications were associated with slightly lower rates of visits compared to phentermine.

During the first year of treatment, phentermine users had a lower risk of emergency department (ED) visits or hospitalizations compared to the other cohorts. By year 3, liraglutide patients had the lowest rates of ED visits and hospitalizations.

Implications for Managed Care

This study illustrates how care costs can pose a significant access barrier for patients with obesity. Despite newer medications being more effective, their clinical benefits may be outweighed by high drug costs, which are associated with high rates of treatment discontinuation.

“These findings support the need for strategies to improve patients’ ability to durably access treatment, in part by reducing the cost of [obesity medications] themselves.”

Reference

Lewis KH, Zhang F, LeCates RF, et al. Health care costs and use of patients prescribed four different obesity medications. Obes. 2026;34(6):1331-1342. doi:10.1002/oby.70208