Tirzepatide: 6-month US persistence data

Roughly two-thirds of US adults who started tirzepatide for obesity or overweight were still taking it six months later, according to a claims-database study published in Diabetes, Obesity and Metabolism on 10 August 2026^[1]. The finding matters because persistence on any chronic-disease medicine is one of the stronger predictors of whether the clinical benefit seen in controlled trials transfers to everyday practice.

The study, led by Theresa Hunter Gibble and colleagues at Eli Lilly and the Healthcare Integrated Research Database (HIRD), tracked 22,512 adults who initiated tirzepatide between November 2023 and June 2024. Participants had no prior dispensing of a GLP-1 or GIP receptor agonist, had obesity or at least one weight-related complication, and were followed for six months post-initiation.

What the numbers show

Of the 22,512 initiators, 68% (n=15,208) remained persistent over the six-month period, defined as no gap of more than 45 days between fills^[1]. Adherence, measured by a proportion of days covered (PDC) of at least 80%, was somewhat lower: 55% (n=12,292) met that threshold. The two figures are not the same thing. Persistence captures whether someone stayed on the drug at all; adherence captures whether they stayed on it consistently enough to be expected to benefit.

Among the subset with weight recorded in the database (n=808), mean body weight fell by 10.5% at six months^[1]. The subgroup with no prior GLP-1 experience saw slightly larger reductions, at 12.0%. The authors also report numerical improvements in cardiometabolic markers, though the abstract does not give specific figures for blood pressure or lipid panels.

Who was in the study

The cohort was predominantly female (73%) with a mean age of 46 years^[1]. Ninety-one percent had at least one obesity-related complication on record. The most common were dyslipidemia, hypertension, and anxiety. The analysis used administrative claims and electronic health records from the HIRD, with 12-month pre-index and 6-month post-index enrollment requirements to ensure continuity of data.

What real-world persistence data adds beyond trials

The key SURMOUNT trials enrolled selected participants under close follow-up with scheduled injection training and regular clinic contact. Real-world claims data captures what happens when tirzepatide is prescribed outside that structure. A 68% six-month persistence rate is not directly comparable to trial completion rates, but it provides a baseline for what payers, prescribers, and health systems can expect from a general initiating population.

A parallel UK cohort study published days earlier in the same journal, drawing on 630,545 patients from a digital prescribing service, found that patients who ordered regularly lost more weight^[2]. The UK data showed 13.5% mean weight loss at six months among those with recorded weights, and 17.4% at twelve months, with persistence correlated with area-level socioeconomic status.

A 2026 narrative review of GLP-1 receptor agonist discontinuation noted that many patients stop treatment but that this is often nonpermanent, and that inconsistency in how persistence is defined across studies makes cross-study comparison difficult^[3]. The Gibble study addresses that last point by reporting both persistence (gap-based) and adherence (PDC-based) separately.

Caveats worth reading before drawing conclusions

Several limitations apply. First, the study is funded by Eli Lilly, the manufacturer of tirzepatide (Zepbound/Mounjaro), which means the design and reporting choices should be read with that in mind^[1]. Second, weight data was available for only 808 of the 22,512 initiators, so the 10.5% weight-loss figure describes a small and potentially selected subset rather than the full cohort.

Third, the study period runs November 2023 through June 2024, which is early in the US commercial launch of tirzepatide for obesity (Zepbound was approved November 2023). Persistence patterns may differ as the prescribing population broadens and as drug shortages, coverage decisions, and patient expectations evolve.

Fourth, administrative claims capture fills, not injections. A filled prescription that goes unused shows as persistence even if the patient stopped injecting. This is a standard limitation of pharmacy-claims methodology and not specific to this study.

What we do not yet know

The study does not report what drove the 32% of patients who discontinued within six months. Cost, side effects, insufficient weight loss, and insurance coverage changes are all plausible explanations, but the claims database cannot distinguish between them. The 2026 GLP-1 discontinuation review identified patient behavior and healthcare system factors as understudied dimensions^[3]. Twelve-month and longer-term persistence data from this cohort are also not yet available.

For per-country access and coverage information that affects whether patients can stay on tirzepatide long enough to benefit, see the tirzepatide regulation pages.

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