Tirzepatide one-year persistence holds near 65% while semaglutide rate climbs
Claims data show one-year persistence on weight-loss GLP-1 drugs has risen sharply since 2021, though about a third of patients still stop within a year.
Real-world claims data show that about two-thirds of commercially insured US adults without diabetes stayed on tirzepatide (Zepbound) for a full year, while one-year persistence on semaglutide (Wegovy) rose sharply between 2021 and mid-2024 [1].
The analysis drew on Prime Therapeutics' integrated medical and pharmacy claims, covering an average monthly membership of 17.9 million commercially insured people. Researchers identified 62,650 members without diabetes who newly started a high-potency, weight-loss-indicated GLP-1 receptor agonist between January 1, 2021, and June 30, 2024. Of those, 33,607 (53.6%) met the full study criteria, which included continuous enrollment and no prior GLP-1 claim in the year before starting. The mean age was 45.7 years, and 75.5% were female [1].
The study measured persistence as no more than a 60-day gap between the end of one prescription's days supply and the next fill within the 365 days after the first claim. Patients who switched from one GLP-1 product to another were still counted as persistent. The researchers also measured adherence, defined as covering at least 80% of days, but adherence rates are not reported in the abstract [1].
Across all products in the study, one-year persistence rose from 33.2% for people who started in 2021 to 60.9% for those who started in the first half of 2024. For semaglutide, the yearly rates were 33.2% in 2021, 34.1% in 2022, 39.8% in 2023, and 58.6% in the first half of 2024. For tirzepatide, persistence was 64.0% in 2023 and 64.8% in the first half of 2024 — the only periods in which that product was available inside the study window [1].
The authors wrote that the resolution of GLP-1 shortages may have improved persistence. They also pointed to better dose escalation, better management of side effects, and weight-loss lifestyle programs as possible factors. They said more research is needed to understand why people stop treatment and to assess the long-term cost-effectiveness of these drugs [1].
The findings come with limits. The data cover commercially insured people only, so they do not describe Medicare, Medicaid, or uninsured patients. Everyone in the sample had no diabetes diagnosis or diabetes drug claim in the year before starting, so the results do not apply to people using these drugs for type 2 diabetes. Four of the authors are employed by the study sponsor, Prime Therapeutics, which is listed as a conflict of interest [1].
Why it matters for patients
Staying on treatment is not the same as success, but it is part of how these drugs work outside clinical trials, where the weight-loss results depended on people continuing therapy. This analysis suggests that staying on a GLP-1 for a year has become more common since 2021, when supply problems and shifting coverage disrupted treatment for many patients [1].
The gap between the two products is also notable. One-year persistence on tirzepatide stayed near 65% in both periods measured, while semaglutide's rate reached 58.6% in the first half of 2024. The study does not explain the difference, and the two drugs were not compared head-to-head in a trial here; these are observational claims data [1].
Because the study counted patients as persistent even if they switched products, the numbers reflect continued GLP-1 treatment overall rather than loyalty to one brand. Cost, insurance coverage changes, side effects, and supply are all factors patients and clinicians weigh, though the analysis does not break out which of these drove the trends it found [1].
What is not yet known
The analysis does not report why people stopped treatment, how much weight they lost, or whether they restarted later. It also does not report adherence rates, only the definition used to measure them. The authors state that additional research is needed on reasons for discontinuation and on the long-term cost-effectiveness of these treatments [1].
No publication date for the analysis is given in the record reviewed, and no timeline for follow-up studies has been disclosed [1].
One detail worth keeping in mind: the study tracked only the weight-loss-indicated versions of these molecules — Wegovy and Zepbound. It did not include Ozempic, Rybelsus, or Mounjaro, which are used for type 2 diabetes, and it excluded people with a diabetes diagnosis [1].
Sources
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