Lilly-funded study finds lower health costs for Zepbound users over 55

A peer-reviewed study funded by Eli Lilly found that adults over 55 who stayed on Zepbound (tirzepatide) for weight management had lower monthly health care costs than matched adults who started no similar medication, and that the gap widened over 18 months ^[1][2]. The analysis, published online August 24, 2026 in Diabetes, Obesity and Metabolism, excluded the cost of Zepbound itself ^[1][2].

The study matched 15,843 people who started tirzepatide 1:1 with 15,843 people who started no GLP-1 or GIP/GLP-1 medication, drawing on de-identified claims from Komodo's Healthcare Map ^[1][2]. Participants were over 55 (mean age 64.5), had obesity or overweight plus at least one obesity-related complication, and had no type 2 diabetes ^[2]. Everyone had at least 12 months of continuous enrollment before the study period, and tirzepatide initiations ran from November 2023 to September 2025 ^[2].

In the primary analysis, monthly all-cause costs in the tirzepatide group moved from $1,061 at baseline to $955 over 18 months, while costs in the untreated group rose from $1,031 to $1,244 ^[1]. The difference was $145 per person per month at 6 to 12 months (95% CI, -266 to -25; P = .022), a 12.3% relative reduction, and $319 per person per month at 12 to 18 months (95% CI, -544 to -94; P = .015), a 25.4% relative reduction, both favoring the treated group ^[1]. A secondary method that compared matched pairs directly produced larger gaps — $181 and $607 per person per month in the same windows ^[1]. Lilly described the secondary results as up to 15% and up to 38% lower costs ^[2]. The authors treated the reweighted method as primary because fewer than 10% of patients remained uncensored by the 12- to 18-month mark ^[1].

The cost gap tracked hospital use. Treated patients had a more favorable change from baseline in combined inpatient admissions and emergency department visits at every follow-up window, with incidence rate ratios of 0.86 at 3 to 6 months (P = .033), 0.76 at 6 to 12 months (P = .001) and 0.69 at 12 to 18 months (P = .021) ^[1]. Outpatient and office visit rates did not differ significantly, though treated patients had numerically more of them, a pattern the authors said may reflect greater engagement with routine care after starting treatment ^[1][2].

The findings arrive as the Centers for Medicare & Medicaid Services runs its GLP-1 Bridge program, an 18-month demonstration that subsidizes access to incretin-based weight management drugs, including tirzepatide, semaglutide and orforglipron, for eligible beneficiaries ^[1]. Under the negotiated pricing cited in the study, beneficiaries pay a $50 copay on a $245 30-day supply, leaving Medicare a net cost of $195 per month ^[1]. The authors wrote that the $319 monthly offset at 12 to 18 months "has implications" for that $195 figure ^[1]. Lilly said savings beginning at six months nearly covered the program's monthly treatment cost and that from 12 months they exceeded it ^[2].

"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 ^[2].

Why it matters for patients

The reported savings are offsets elsewhere in care, not a reduction in the price of the drug. Claims data do not capture Zepbound's net price, so the study removed drug cost from the totals and measured only spending on other care ^[1][2]. A separate July 2026 Institute for Clinical and Economic Review analysis found that medical cost offsets from GLP-1 therapies had appeared mainly in patients with both obesity and diabetes using injectable agents, while obesity-only populations often saw increased spending ^[1]. That analysis put tirzepatide's cost at $57,779 per quality-adjusted life-year versus lifestyle modification alone, the lowest of the GLP-1 options it reviewed, but warned that treating just 1% of eligible patients would exceed its roughly $880 million annual budget impact threshold ^[1].

The benefit applied only while patients stayed on treatment; anyone who discontinued was censored from the analysis at that point, and the authors said the results cannot be extended to people after they stop the drug ^[1].

The authors also could not capture tirzepatide obtained through cash pay, compounding or directly from the manufacturer, which may have misclassified some people in the untreated group and could understate the true cost difference ^[1]. They said residual confounding from unmeasured factors such as socioeconomic status and health literacy cannot be excluded, and that claims data are subject to coding and misclassification errors ^[1].

Not every pharmacy stakeholder sees the economics as favorable. "I just don't think that GLP-1s, or any expensive brand medication necessarily, are really great investments for local independent pharmacies," Jay Bregman, founder and CEO of Andel, told Drug Topics ^[1].

What happens next

The Medicare GLP-1 Bridge is an 18-month test program. According to Bryan Wheeler, PharmD, a staff pharmacist at three Tennessee pharmacies, the Centers for Medicare & Medicaid Services "will use this program to decide if these drugs should be a permanent part of Medicare" starting July 1, 2026 ^[1]. Lilly said it expects the results to help shape coverage decisions by payers, states and employers ^[2]. Whether this study changes coverage has not been reported, and no follow-up analyses from the same dataset have been announced ^[1].