Lilly study links Zepbound to lower medical costs in adults over 55

Eli Lilly said Aug. 26, 2026 that a company-funded real-world study found adults over 55 with overweight or obesity who stayed on Zepbound (tirzepatide) had lower medical costs than similar adults who were not treated ^[1]. The results were published in the journal Diabetes, Obesity and Metabolism, and Lilly described them as the first of their kind in this age group ^[1][2].

What the study measured

The retrospective study used claims data from Komodo's Healthcare Map, which includes de-identified records for more than 330 million people enrolled in U.S. health plans. It included 15,843 adults over 55, with an average age of 64.5, who had obesity (BMI of 30 or higher) or overweight (BMI of 27 or higher) plus at least one obesity-related complication, and who started Zepbound between November 2023 and September 2025. Each was matched 1-to-1 with a control who met the same criteria but did not start any GLP-1 or GIP/GLP-1 medication. Matching used baseline demographics, clinical characteristics, obesity-related complications and prior healthcare use. All participants had at least 12 months of continuous insurance enrollment before the study period ^[1].

Researchers excluded the cost of Zepbound from total treatment costs, saying claims data do not capture the drug's net price. The reported differences therefore reflect potential savings that could offset the price of Zepbound, not the net cost impact of treatment overall ^[1].

At six months, the analysis that directly compared matched pairs found costs 15% lower, a difference of $181 per patient per month. The second method, which reweighted results so that patients who left the study early were still represented, found 12% lower costs, or $145 per patient per month ^[1]. At 12 months, the pairwise analysis estimated a difference of $607 per patient per month, or 38% lower on average, while the reweighted analysis estimated $319 per patient per month, or 25% lower ^[1].

Lilly said the estimated savings nearly covered the Medicare GLP-1 Bridge program's monthly treatment cost of $195 per patient starting at six months, and exceeded the cost of Zepbound treatment starting at 12 months ^[1].

In the primary analysis, people treated with Zepbound had lower rates of hospital admissions and emergency department visits at every follow-up period, and numerically higher rates of routine outpatient and office visits, which Lilly said was consistent with greater engagement in routine care. Lilly noted that those differences were numerically lower in the secondary pairwise analysis but were not statistically significant there ^[1]. The study was an observational analysis of claims, not a randomized trial.

"This compelling real-world evidence highlights the impact that treating obesity with Zepbound can have on older patients and the healthcare system," said Ilya Yuffa, executive vice president and president of Lilly USA and Global Customer Capabilities ^[1][2]. "This analysis shows treatment costs can be lowered, and in some cases more than covered, by savings elsewhere in care – including for payers and in Medicare," he said, adding that the data "should help shape decisions" as coverage expands across Medicare, states and employers ^[1][2].

The release came the same week as a Business Group on Health survey that found 60% of employers covered GLP-1 drugs for weight loss in 2026, down from 72% in 2025 ^[2]. Business Group CEO Ellen Kelsay said the cost of these drugs is forcing employers to consider trade-offs in access, and that benefits were taking time to materialize ^[2]. In Medicare, the temporary Bridge program launched July 1 and runs through the end of 2027, while a broader coverage model, in which insurers would cover the cost, has been delayed indefinitely ^[2]. Lilly and rival Novo Nordisk both participate in the Bridge program ^[2].

Why it matters for patients

The study speaks to a question that shapes whether insurers and employers pay for these drugs: whether medical savings outside the drug's own price offset its cost. Because the analysis excluded Zepbound's price, it does not show a net cost or net savings figure, and Lilly said claims data do not capture the drug's net price ^[1]. Whether any savings identified would translate into lower premiums or broader coverage for patients has not been reported. The comparison group received no GLP-1 or GIP/GLP-1 medication at all, so the study does not compare Zepbound with semaglutide or other treatments ^[1]. The two analytic methods also produced different totals, with the company reporting a range of $319 to $607 per patient per month at 12 months depending on the model ^[1].

What happens next

The Medicare GLP-1 Bridge program is scheduled to remain in place through the end of 2027 ^[2]. A broader Medicare coverage model that would shift costs to insurers has been delayed indefinitely, and no new date has been announced ^[2]. Lilly said the study data should help shape coverage decisions by Medicare, states and employers ^[1].