A prescription can look simple on paper: start treatment, follow the plan and check in later. In real life, an appointment gets delayed, coverage changes or side effects make the next step uncertain.
Researchers use the word “persistence” to describe whether people appear to keep taking a treatment over time. It’s a useful question, but the answer depends on how the study defines a gap and what records it can see.
What does persistence mean in a study?
One study used pharmacy and medical claims from commercially insured adults without diabetes who started certain weight-management medicines. It looked for continued treatment over a year, allowing people to switch between the studied products and allowing a gap of up to 60 days between the end of one supply and the next fill.
Under that definition, one-year persistence was about a third among people who started in 2021 and about three in five among those who started in the first half of 2024. The study included 33,607 people who met its enrollment and other criteria.
Those numbers describe groups within that insurance dataset. They are not the odds that any one reader will continue treatment, and they don’t cover every way people pay for or receive care.
A refill record has limits
A pharmacy claim can show that a prescription was filled. It cannot prove that every dose was taken, explain every pause or show a conversation that happened outside the records available to the researchers.
The rules also affect the result. A study that allows a 60-day gap and switching may count people differently from one that uses a different gap, follows a single product or relies on prescriptions in an electronic health record. Two percentages can differ without either describing the same group in the same way.
It helps to look at the dates too. Supply, coverage and the treatments people could access changed over the period studied. Researchers suggested several possible explanations for the trend, but the claims did not establish a reason for each interruption.
Why might someone stop?
In a separate health-system study, documented reasons included being lost to follow-up with the original prescriber, side effects and loss of insurance coverage. Those findings describe that clinic’s records; they aren’t a complete list for everyone.
A pause may be planned with a clinician, related to an unrelated illness, or prompted by a practical problem. Sometimes a person changes treatment. Sometimes the record simply doesn’t capture what happened next.
That is why it’s unhelpful to treat every gap as a lack of motivation. Access and tolerability are part of a treatment plan, not footnotes to it.
How is this different from a clinical trial?
Trials often provide scheduled visits, study procedures and follow-up within a defined research setting. Real-world data can add a view of what happens in ordinary care, but the groups may differ and the records may be incomplete.
Neither kind of study answers every question. A randomized trial can help compare treatments; a claims study can help describe patterns across covered patients. The best interpretation keeps the strengths and limits of each in view.
Make room for practical questions
If your own plan is getting harder to follow, say what’s getting in the way. That could be nausea, an upcoming change in coverage, travel or uncertainty about a missed appointment. Your care team can help consider the next step.
If treatment has been interrupted, ask your prescriber for product-specific guidance before restarting an old supply. Our article on how long GLP-1 treatment might last has more questions for that conversation.
A refill record is useful evidence, but it isn’t the whole story. The practical details are worth discussing before a small obstacle becomes a longer gap.