ObesityWeek 2026: Studies Map GLP-1 Access Gaps, Obesity's Costs

The number of Medicare beneficiaries with obesity has more than doubled over the past 25 years, while more than one-third of initial prior authorization requests for glucagon-like peptide-1 (GLP-1)–based therapies were denied in a large cohort of clinically eligible, commercially insured adults, according to research presented at ObesityWeek 2026, The Obesity Society's annual meeting held November 14-17 in National Harbor, Maryland.^1,2

Additional research demonstrates how obesity-related conditions erode work productivity, how patients titrate semaglutide and tirzepatide outside of trials, and what happens to medical costs when patients stay on therapy for a year. All of the observational analyses include coauthors affiliated with Amgen.

Here are 5 key takeaways:

1. Medicare Beneficiaries With Obesity Climb to 24.6 Million

Using National Health and Nutrition Examination Survey data from 1999-2000 through 2021-2023, an analysis estimated trends among adults 65 years and older who self-reported Medicare coverage (n = 14,916).¹ Over that period, the estimated number of Medicare beneficiaries in that age group rose from 28.8 million to 60.9 million.

Obesity prevalence (body mass index [BMI] ≥ 30 kg/m²) increased from 33.6% (95% CI, 29.9%-37.3%) to 40.5% (95% CI, 37.6%-43.4%), meaning the number of beneficiaries with obesity grew from 9.7 million to 24.6 million. Severe obesity (BMI ≥ 40 kg/m²) rose from 4.5% to 7.4%, or from 1.3 million to 4.5 million people. The pace also accelerated: the number of beneficiaries with obesity grew by 0.54 million per year through the 2013-2014 cycle and by 1.16 million each year after that.

Obesity-related conditions were far more common among beneficiaries with obesity or severe obesity in 2021-2023 than among those without obesity, including diabetes (40.2% and 53.0% vs 19.4%), metabolic dysfunction–associated steatohepatitis (17.4% and 21.4% vs 3.2%), and heart failure (11.4% and 23.3% vs 6.2%). Hypertension and arthritis followed the same pattern.

The data arrive as Medicare begins covering obesity medications for the first time. Medicare has historically been barred by law from covering drugs used specifically for weight loss, but under the Medicare GLP-1 Bridge demonstration, eligible Part D enrollees have had access to select GLP-1 therapies for weight reduction at a $50 monthly co-pay since July 1, 2026, with coverage now extended through December 31, 2027.³

2. Indirect Costs Rise With Each Obesity-Related Condition

A second analysis examined productivity loss among 31,772 adults with a BMI of 27 kg/m² or higher from the 2024 US National Health and Wellness Survey.⁴ The researchers focused on 5 cardiorenal and cardiometabolic obesity-related conditions (ORCs): atherosclerotic cardiovascular disease, chronic kidney disease (CKD), heart failure, obstructive sleep apnea (OSA), and type 2 diabetes (T2D).

Nearly one-third of respondents (31.8%) had at least 1 of these conditions, and 9.5% had at least 2. OSA (16.5%) and T2D (15.1%) were the most common.

Productivity loss increased in a stepwise fashion as ORC burden grew (all P < .001). Compared with respondents without any of the conditions, those with at least 1 or at least 2 ORCs reported higher overall work impairment (23.8% vs 32.7% vs 36.7%), presenteeism (20.1% vs 29.1% vs 33.1%), and activity impairment (24.3% vs 36.8% vs 43.9%).

Mean annual indirect costs climbed from $10,582.50 for those without ORCs to $15,718.00 for those with at least 1 and $19,611.60 for those with at least 2. CKD and heart failure carried the heaviest burden, with overall work impairment of 63.8% and 46.5%, respectively, and mean annual indirect costs of $22,076.4 and $23,207.6. The authors suggested future research evaluate whether a multimorbidity-centric treatment approach could reduce the patient and societal burden of obesity.

3. More Than 1 in 3 Initial GLP-1 Prior Authorizations Denied

A late-breaking abstract used deidentified clinical and insurance data from a telehealth platform to examine what happens when clinically eligible, commercially insured adults aged 18 to 63 years seek on-label GLP-1–based therapy for weight management.² Patients had a BMI of 30 kg/m² or higher or a BMI of 27.0 to 29.9 kg/m² with at least 1 ORC, and completed a medication-specific benefits verification between January 1 and September 30, 2025.

Among 225,000 randomly selected patients, coverage without prior authorization was rare: 3.7% for semaglutide and 2.8% for tirzepatide. Coverage with prior authorization was found for 35.7% and 31.1%, respectively, and 27.0% of benefits checks were indeterminate.

Of 69,462 patients with treatment-initiation prior authorization submissions, 53.2% were approved, 35.7% were denied, and 11.2% had unknown outcomes. The most common denial reasons were plan exclusions or coverage limitations (51.1%); unmet clinical eligibility criteria such as BMI, diagnosis, or comorbidity requirements (24.7%); and unmet therapy requirements such as a prior medication trial (12.7%).

Patients with a BMI of 27.0 to 29.9 kg/m² and at least 1 ORC had the highest denial rate of any BMI group (38.7%), and 41.7% of those denials were attributed to unmet clinical eligibility criteria. Plan exclusions and coverage limitations were most common among patients with a BMI of 40 kg/m² or higher (56.7%). Across benefits verification and prior authorization outcomes, results varied more by payer or pharmacy benefit manager and by region than by patient demographics or measured clinical characteristics.

The authors wrote that the findings point to a gap between treatment eligibility and real-world access and called for research into benefit design and policy strategies to reduce barriers to standard-of-care obesity treatment.

4. Most Patients Titrated More Slowly Than the Label Recommends

Semaglutide and tirzepatide labeling recommends dose increases every 4 weeks until patients reach a maintenance dose. However, new research shows that real-world dosing departed from the label. Researchers identified 5134 new users who began semaglutide (n = 2809) or tirzepatide (n = 2325) for chronic weight management in 2024.⁵ Patients had a mean age of 48.8 years and a mean BMI of 37.9 kg/m²; 72.4% were female.

Latent class modeling identified low-, moderate-, and high-dose trajectories over the first 6 months for each drug. Only the high-dose trajectories reflected, on average, a dose increase every 4 weeks, and they accounted for 25.1% of semaglutide users (mean weekly dose, 2.4 mg) and 12.7% of tirzepatide users (mean weekly dose, 13.5 mg). The largest groups followed low-dose trajectories, averaging 0.9 mg of semaglutide (45.1%) and 5.5 mg of tirzepatide (48.0%).

The relationship between dose trajectory and persistence differed by drug. For semaglutide, 6-month persistence was higher in the moderate- (90.3%) and high-dose (89.7%) trajectories than in the low-dose trajectory (78.1%; P < .001), and adherence followed the same pattern. For tirzepatide, the low-dose trajectory had the highest persistence (87.3%) compared with the moderate (82.7%) and high (77.0%) trajectories (P < .001), while adherence did not differ significantly across groups (P = .50).

Keeping patients on therapy has been an ongoing concern for payers and pharmacy benefit managers: in real-world obesity cohorts without diabetes, roughly one-third of patients remain on GLP-1 therapy at 1 year.⁶

5. 12-Month Persistence Linked to Lower Medical Costs

The final abstract examined whether persistence translates into lower downstream spending.⁷ Using Optum Market Clarity data from 2020 to 2025, the researchers followed 27,013 adults with obesity or overweight who initiated injectable semaglutide or tirzepatide. Patients were grouped by whether they stayed on their initial therapy without a gap of more than 60 days for 12 months or discontinued within 3 months, 3 to less than 6 months, or 6 to less than 12 months. Medical costs and use were then compared over the following 6 months.

In this cohort, 41.9% of patients (n = 11,320) remained persistent for at least 12 months. After adjusting for demographics, comorbidities, the COVID-19 pandemic period, and baseline costs, the persistent group had the lowest mean total medical costs of the 4 cohorts, which corresponded to a $1422 to $2400 reduction in mean costs compared with the discontinuation cohorts.

Similar patterns appeared across cost components, including acute care. Compared with patients who discontinued, persistent patients had 22% to 24% fewer emergency department (ED) visits (0.30 vs 0.38-0.40 per patient), 19% to 29% lower ED costs ($786 vs $978-$1110), and 27% to 42% fewer inpatient admissions (0.04 vs 0.06-0.07 per patient). The analysis focused on inpatient, outpatient, and ED medical costs; the abstract did not report pharmacy spending.

References

1. Muntner P, Jaeger BC, Bittner V, et al. Increasing burden of obesity and severe obesity among Medicare beneficiaries, 1999–2023. Presented at: ObesityWeek 2026; November 14-17, 2026; National Harbor, MD.
2. Broffman L, Smith BJ, Manalac R, et al. Clinical eligibility and coverage gaps for GLP-1–based receptor agonists in patients with obesity. Presented at: ObesityWeek 2026; November 14-17, 2026; National Harbor, MD.
3. Freed M, Cubanski J, Williams E. What to know about the BALANCE model for GLP-1s in Medicare and Medicaid and the Medicare GLP-1 Bridge. KFF. May 11, 2026. Accessed November 12, 2026. https://www.kff.org/medicare/what-to-know-about-the-balance-model-for-glp-1s-in-medicare-and-medicaid/
4. Galindo RJ, Grasic K, Wang M, et al. Productivity loss and indirect costs of obesity-related conditions in adults with overweight/obesity. Presented at: ObesityWeek 2026; November 14-17, 2026; National Harbor, MD.
5. Chao AM, Sagendorf TJ, Anderson LJ, et al. Semaglutide and tirzepatide dose escalation trajectories and treatment utilization. Presented at: ObesityWeek 2026; November 14-17, 2026; National Harbor, MD.
6. Sisodia A. Predicting GLP-1 discontinuation from pharmacy claims. Am J Manag Care. 2026 Aug;32(8):426-428. doi:10.37765/ajmc.2026.89993
7. Cai K, Malik R, Yang H, et al. Medical cost and use by GLP-1 RA persistence status in US patients with obesity/overweight. Presented at: ObesityWeek 2026; November 14-17, 2026; National Harbor, MD.