When a study asks whether people stay on GLP-1 drugs, the usual answer is a single number: what fraction are still filling prescriptions a year later. A new analysis in Diabetes, Obesity and Metabolism ↗ argues that the single number hides the more useful story, which is that people do not divide neatly into stayers and quitters but into several distinct patterns of use.
The researchers pulled commercial insurance claims from the MarketScan database, covering 2021 to 2023, for people aged 10 and up who started a GLP-1 receptor agonist for obesity and did not have diabetes. That gave them 201,229 adults and 1,139 children and teenagers. Instead of averaging everyone's adherence together, they used a method called group-based trajectory modeling, which sorts people by the shape of their month-to-month use over the first year rather than by a single endpoint.
Adults sorted into five groups. About 19.6% were immediate discontinuers, who filled once or twice and stopped. Another 23.5% were early discontinuers, who dropped off within the first few months. 20.7% were late discontinuers, who held on longer before fading out. A small group of 5.5% used the drugs intermittently, on and off across the year. And 30.7% were persistent users who stayed on treatment. The gap between the groups was wide. Measured as proportion of days covered, which is the share of days a person actually had the drug on hand, the average ran from 0.10 in the lowest group to 0.87 in the persistent group.
So the headline number, that roughly a third of adults are still on the drug at a year, is real, but it sits on top of four different ways of not staying on it. An immediate discontinuer and a late discontinuer both count as non-adherent at twelve months, yet they are not the same patient and they do not call for the same response.
The children and teenagers split into five groups too, but more evenly. Each pattern held roughly a fifth of the pediatric cohort, and the persistent group was smaller than in adults at 20.3%. That is a notable difference. Pediatric obesity guidelines increasingly support GLP-1 drugs for adolescents, and this is one of the first real-world looks at whether that population stays on them. The early read is that they stay on at a lower rate than adults, and more of them land in the on-and-off patterns.
Geography mattered more than expected. Compared with people in the South, those in the Northeast were more likely to be persistent users, with an odds ratio of 1.32 in adults and 1.65 in children. An odds ratio of 1.65 means the pediatric patients in the Northeast were about two-thirds more likely to sustain treatment than their Southern counterparts. Claims data cannot say why, but the size of the regional gap points at access, cost, and coverage rules that vary by state rather than at anything about the patients themselves.
The drugs behind these numbers are the familiar ones. Semaglutide ↗ and tirzepatide ↗ dominate obesity prescribing, with liraglutide ↗ the older option, and all of them act on the GLP-1 receptor ↗, with tirzepatide adding a second action at the GIP receptor ↗.
This lands next to an earlier finding covered here ↗ that fewer people quit GLP-1 drugs overall than assumed, but more of those who quit did so because of side effects. The trajectory analysis is the natural next step. It stops treating adherence as a coin flip and starts treating it as a set of distinct paths, which is what a clinician deciding when to check in on a patient actually needs.