Estimating the Impact of Obesity Medications on Clinical and Economic Outcomes

The goal of this observational study is to identify the impact of incretin-based obesity medications (e.g., GLP-1 and GLP-1/GIP) on health and economic outcomes among adults who get their health insurance through their employers. The main questions it aims to answer are:

1. Is obesity medication usage is associated with reduced body mass index (BMI) and weight?
2. Is obesity medication usage is associated with reduced utilization of emergency department and inpatient care or obesity-related conditions over time?
3. Is obesity medication usage is associated with increased utilization of outpatient care over time?
4. Is obesity medication usage is associated with slower growth in direct medical costs over time?
5. Is obesity medication usage is associated with improvements in health measures?
6. Is obesity medication usage associated with reduced workplace costs?

Researchers will compare individuals who have prescriptions for obesity medications to those without to see if differences in health and costs of care exist.

The study uses existing medical and pharmacy claims data.

Study Overview

• Status: Enrolling by invitation
• Conditions: Obesity
• Intervention / Treatment: Drug: Incretin-based therapies (GLP-1 and GLP-1/GIP)

Detailed Description

Incretin-based therapies that work by mimicking the action of the natural hormone GLP-1 and GLP-1/GIP have garnered the most excitement and demonstrated promising results in the management of obesity. This project seeks to estimate the impact of incretin-based obesity medications on clinical and economic outcomes in real-world settings. It proposes to fill gaps in the current literature by focusing on patients from self-insured organizations, measuring direct and indirect costs, establishing a long-term cohort, and by merging claims with electronic health record (EHR) data for more comprehensive measures.

The impact of incretin-based obesity medications on clinical and economic outcomes will be assessed in a dynamic cohort design. The cohort will be drawn from the employees and their working age dependents of large, self-insured (or "self-funded") organizations in the state of Indiana (i.e., "employers"). Employer organizations agreeing to participate will provide medical and pharmacy claims as well as data on workplace performance (if available) from 2018-2029. The primary exposure of interest is documented receipt of any GLP-1 obesity medication (regardless of manufacturer or brand name). A series of fixed-effects regression models will estimate the association between exposure to incretin-based obesity medications and clinical, utilization, and cost outcomes. This dynamic cohort approach, 1) individuals and participating employer organizations may enter and exit the cohort over time and 2) individuals may switch between on or off exposure over time.

• Study Type: Observational
• Enrollment (Estimated): 125000

Contacts and Locations

Study Locations

• United States
  • Indiana
    • Indianapolis, Indiana, United States, 46203
      • Indiana University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Working-age adults and their adult dependents who receive their health insurance coverage from participating, self-insured Indiana employers.

Description

The study cohort is limited to employees and adult dependents aged 18-64 who receive their health insurance coverage from self-insured Indiana employers that agree to participate in the study.

To be included in the study, the individuals must:

1. Be an Indiana resident;
2. Have health insurance benefits provided by participating employers (includes employees and dependents);
3. Be between the ages of 18 and 64;

4. Meet the eligibility criteria for an obesity medication prescription:

   1. BMI of ≥ 30 (obesity) or
   2. BMI of ≥ 25 (overweight) and at least one body weight-related comorbid condition (e.g., hypertension, dyslipidemia, type 2 diabetes mellitus, obstructive sleep apnea, or cardiovascular disease). If the prescribing eligibility criteria are updated in the future, we will update accordingly.
5. Individuals must have at least 6 months of enrollment prior to study inclusion (i.e., prior to the index date), though we may use additional pre-treatment data if available.

An individual who meets any of the following criteria will be excluded from participation in the cohort:

1. Has a condition associated with weight loss: a diagnosis of cancer (except for non-melanoma skin cancer), pancreatitis, eating disorders (e.g., anorexia nervosa and avoidant restrictive food intake disorder), HIV, unintentional weight loss, or cirrhosis at baseline;
2. Has a condition for which obesity medications are contraindicated (for example, medullary thyroid carcinoma, multiple endocrine neoplasia, etc.).
3. Receipt of diabetes-indicated incretin-based medications. If an individual has a claim for a related incretin-based therapy diabetes medication (e.g., Mounjaro, Ozempic, Rybelsus, Victoza) without an obesity-medication claim during the study period, the individual will be excluded from analysis.
4. Prior bariatric surgery.
5. Evidence of prior use of incretin-based obesity medications for weight loss.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Persistent use of incretin-based obesity medication; Persistent use is defined as continuous treatment with no gaps greater than 60 days between prescription fills. Discontinuation is defined as a gap exceeding 60 days following the expected end date of a prescription fill (based on days' supply). Exposure will be measured longitudinally from the index date until discontinuation or censoring. Days of supply will be calculated from pharmacy claims, and we will account for stockpiling by allowing early refills to extend coverage forward in time. If days' supply is missing, it will be imputed using prescribing guidelines or external data sources.	Drug: Incretin-based therapies (GLP-1 and GLP-1/GIP); Documented receipt of any GLP-1 and GLP-1/GIP obesity medication during an observation period.; Other Names: Liraglutide; Saxenda; Wegovy; Semaglutide; Zepbound; Tirzepatide
No documented receipt of incretin-based obesity medication during observation period; Working-age adults (age 18 to 64) insured by participating Indiana-based employers that do not use any incretin-based obesity medication for weight loss. Identified by no claim for obesity medications (accounting for days supply and available refills).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in subject body weight.	Measured in pounds.	6 months periods from 2018 to 2029
Change in subject body mass index (BMI).	Defined as Weight (kg) / height (m)2.	6 months periods from 2018 to 2029
Change in obesity and overweight classification.	Body mass index categorized according to Centers for Disease Control & Prevention groupings (i.e., normal, overweight, class 1 obesity, class 2 obesity, class 3 obesity)	6 months periods from 2018 to 2029

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in emergency department visits.	Total visits	6 months periods from 2018 to 2029
Change in obesity-related emergency department visits.	Visit with obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD).	6 months periods from 2018 to 2029
Change in non-obesity related emergency department visits.	Visit without any of the following: obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD).	6 months periods from 2018 to 2029
Change in preventable emergency department visits.	Preventable visits include those that are: non-emergent (the patient's initial complaint, presenting symptoms, vital signs, medical history, and age indicated that immediate medical care was not required within 12 hours), or; emergent/primary care treatable (based on information in the record, treatment was required within 12 hours, but care could have been provided effectively and safely in a primary care setting. The complaint did not require continuous observation, and no procedures were performed or resources used that are not available in a primary care setting), or; preventable/avoidable (Emergency department care was required based on the complaint or procedures performed/resources used, but the emergent nature of the condition was potentially preventable/avoidable if timely and effective ambulatory care had been received during the episode of illness).	6 months periods from 2018 to 2029
Change in non-preventable emergency department visits.	Non-preventable visits are defined as emergency department care was required and ambulatory care treatment could not have prevented the condition.	6 months periods from 2018 to 2029
Change in inpatient admissions.	Total number of distinct hospitalizations (i.e. admissions).	6 months periods from 2018 to 2029
Change in obesity-related inpatient admissions.	Total hospitalizations with obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD).	6 months periods from 2018 to 2029
Change in non-obesity-related inpatient admissions.	Total hospitalizations without obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD).	6 months periods from 2018 to 2029
Change in inpatient admissions that began in the emergency department.	Total hospitalizations where the subject was admitted from the emergency department.	6 months periods from 2018 to 2029
Change in direct admit inpatient admissions	Total hospitalizations that were admitted directly from the community, i.e. not transferred from the emergency department.	6 months periods from 2018 to 2029
Change in 30 day inpatient readmissions.	Count of hospital admissions (to any facility) occurring within 30 days of a hospital stay.	6 months periods from 2018 to 2029
Change in outpatient visits.	Any in-person office visits with primary care, family medicine, internal medicine, or any specialty (including behavioral health); excludes phone visits. Total visits, as well as separated by obesity-related vs non-obesity related.	6 months periods from 2018 to 2029
Change in obesity-related outpatient visits.	Total in-person office visits with primary care, family medicine, internal medicine, or any specialty (including behavioral health) with any of the following: obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD). Excludes: phone visits.	6 months periods from 2018 to 2029
Change in non-obesity-related outpatient visits	Total in-person office visits with primary care, family medicine, internal medicine, or any specialty (including behavioral health) without any of the following: obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD). Excludes: phone visits.	6 months periods from 2018 to 2029
Change in total medical spending.	All medical costs paid (inpatient, outpatient, emergency department, and rehabilitation costs).	6 months periods from 2018 to 2029
Change in total pharmacy spending.	All pharmacy costs paid.	6 months periods from 2018 to 2029
Change in total pharmacy spending excluding incretin-based medications.	All pharmacy costs excluding the cost of incretin obesity medications	6 months periods from 2018 to 2029
Change in total spending on obesity-related complications	All medical costs paid where the claim is associated with any of the following: obesity-related diagnosis code (E66.1-E66.3, Z68.30-768.45), metabolic syndrome, type 2 diabetes, chronic kidney disease, cardiovascular disease, osteoarthritis of the knee, depression, anxiety, metabolic dysfunction-associated steatohepatitis, nonalcoholic fatty liver disease & steatohepatitis, obstructive sleep apnea, hyperlipidemia, hypertension, cerebrovascular disease, asthma, gastroesophageal reflux disease (GERD), or chronic obstructive pulmonary disease (COPD). Excludes: telehealth / phone visits.	6 months periods from 2018 to 2029

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in absenteeism.	Total number of sick leave days (costs estimated from published estimates or salary information if available).	6 months periods from 2018 to 2029
Change in retention / turnover.	Percent of employees that end employment for any reason.	6 months periods from 2018 to 2029
Change in disability claims.	Total worker's compensation claims regardless of disability period.	6 months periods from 2018 to 2029
Change in clinical A1C laboratory values.	hemoglobin A1C or HbA1c values	6 months periods from 2018 to 2029
Change in blood pressure laboratory values.	Systolic and diastolic	6 months periods from 2018 to 2029
Change in cholesterol laboratory values.	cholesterol blood test (a lipid panel or lipid profile	6 months periods from 2018 to 2029

Collaborators and Investigators

• Sponsor: Indiana University
• Collaborators: Eli Lilly and Company
• Investigators: Principal Investigator: Joshua R Vest, PhD, MPH, Indiana University

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): December 31, 2029
• Study Completion (Estimated): December 31, 2029

Study Registration Dates

• First Submitted: June 3, 2026
• First Submitted That Met QC Criteria: June 8, 2026
• First Posted (Actual): June 10, 2026

Study Record Updates

• Last Update Posted (Actual): June 10, 2026
• Last Update Submitted That Met QC Criteria: June 8, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: GLP-1; Obesity medications; Incretin-based
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Amino Acids, Peptides, and Proteins; Proteins; Glucagon-Like Peptide-1 Receptor; Glucagon-Like Peptide Receptors; Receptors, G-Protein-Coupled; Receptors, Cell Surface; Membrane Proteins; Receptors, Gastrointestinal Hormone; Receptors, Peptide; Gastrointestinal Hormones; Glucagon-Like Peptides; Proglucagon; Liraglutide; Glucagon-Like Peptide 1; Tirzepatide; semaglutide
• Other Study ID Numbers: 00855196; 26469 (Other Identifier: Indiana University)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Raw and derived data at the patient level will not be publicly posted due to our use of secondary data from privately held claims, electronic health records, and health information exchange systems. Because of data use restrictions among the participating employer organizations contributing claims to the analysis and because of the data use restrictions established by consortium agreements among the health system partners contributing EHR data to the project, patient-level data cannot be shared or disseminated beyond this project. Nevertheless, de-identified derived health information exchange data (only) at the patient-level used in this study may be shared with investigators whose formal requests are approved by the data owners. Requests can be sent to askRDS@regenstrief.org. Access to this data requires investigator support and a signed data access agreement between the Regenstrief Institute and the investigator's institution.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes