Zepbound linked to lower healthcare costs in older adults with obesity

Older adults with obesity or that are overweight who stayed on Zepbound (tirzepatide) for weight management had monthly healthcare costs that fell below those of matched, untreated adults, reaching a 25.4% reduction, or about $319 per patient per month, by 12 to 18 months of treatment, according to a study published in Diabetes, Obesity and Metabolism on August 24.

Obesity affects more than 30% of U.S. adults older than 55 and is tied to comorbidities such as cardiovascular disease, diabetes and certain cancers. The study noted Medicare and Medicaid spending on obesity is projected to reach $4.1 trillion over the next decade.

Eli Lilly and Company’s Zepbound combines glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonism and is approved for adults with obesity or who are overweight, including at least one weight-related complication.

These findings were released as CMS rolled out the Medicare GLP-1 Bridge program in July 2026, an 18-month demonstration subsidizing incretin-based weight management drugs at $245 per 30-day supply with a $50 copay ($195 net to Medicare). Part D coverage was previously barred from providing for weight loss alone.

Led by Navneet Upadhyay, a health economics and outcomes researcher at Eli Lilly, and his team, the retrospective cohort study was conducted by using the Komodo Research Dataset, drawn from Komodo Health's Healthcare Map, a claims database covering more than 330 million de-identified U.S. patients.

According to a news release by Eli Lilly, the researchers said their goal was to inform Medicare and payer coverage decisions on weight management drugs.

Using claims data from November 2022 through September 2025, researchers identified adults older than 55 with obesity (BMI of 30 or higher) or overweight (BMI 27 to 29.9) and at least one weight-related comorbidity, with no type 2 diabetes diagnosis, who started Zepbound on or after its Nov. 8, 2023, approval for weight management. Each was matched 1-to-1 by propensity score with an untreated patient; the matched sample included 15,843 patients per group. Costs, excluding the drug’s price, and healthcare use were tracked from a 12-month baseline through 18 months post-treatment using a difference-in-differences approach. Due to untreated patients tended to stay in the data longer, researchers used two methods to handle uneven follow-up: inverse-probability-of-censoring weighting (primary) and pairwise censoring (supporting).

In the beginning, the groups were similar: mean age about 64 years, two-thirds women, and average BMI around 34.8. By 6 to 12 months, costs excluding tirzepatide's price were $145 per patient per month lower, a 12.3% reduction, in the Zepbound group in the primary analysis; by 12 to 18 months, the gap widened to $319, a 25.4% reduction. The supporting pairwise analysis found larger gaps: $181 at 6 to 12 months and $607 at 12 to 18 months. Costs stayed roughly flat in the Zepbound group, while untreated-group costs climbed from $1,031 to $1,244 per month.

Researchers attributed most of the gap to fewer hospital admissions and emergency department visits, most pronounced at 12 to 18 months. Outpatient and office visits were higher among Zepbound patients, possibly reflecting greater routine-care engagement, but not as significant. By 12 to 18 months, the cost gap exceeded the Bridge program's $195 monthly net drug cost in both analyses.

"This compelling real-world evidence highlights the impact that treating obesity with Zepbound can have on older patients and the healthcare system," Ilya Yuffa, executive vice president and president of Lilly USA and Global Customer Capabilities, said in the news release.

Few patients remained by then, though: 1,181 Zepbound and 3,004 untreated patients in the primary analysis, and just 793 pairs, roughly 5% of the original cohorts, in the pairwise analysis. The largest savings estimates reflect patients who stayed on treatment longest, not everyone who started it.

Strengths of the study include its size, its large multi-payer claims dataset and a well-matched comparison group that let researchers separate Zepbound-linked cost trends from broader obesity- and aging-related cost growth; consistent results across both statistical approaches bolstered the authors' confidence in the findings.

Limitations include the steep patient drop-off by 12 to 18 months, which made estimates less precise and ruled out breakdowns by region or race and ethnicity. Findings apply only to patients who stayed on the drug long enough to be captured, not those who discontinued, and don't extend to younger adults or people who got the drug outside insurance claims. Unmeasured factors such as income or health literacy could still explain some of the gap. Since 36% of the cohort started Zepbound during a 2024 supply shortage that may have affected persistence, the authors noted results may not generalize to current use now that supply is stable.

Given those gaps, the study's authors encouraged that future research should look at subgroup differences, including race, ethnicity, and geographic region, and evaluate outcomes using an intention-to-treat approach that accounts for patients regardless of whether they discontinued the drug once longer follow-up data are available.