Tirzepatide Impact Assessment Study

Official title

Tirzepatide Impact Assessment: Exploring Health and Wellness Outcomes

Overview

This study examines how two different weight-loss strategies affect heart and metabolic health, as well as changes at the molecular level in the body. One group includes adults who are starting a GLP-1 receptor agonist medication (i.e., semaglutide or tirzepatide) prescribed by their own doctor for weight loss. The other group includes adults who will participate in a structured lifestyle program combining a reduced-calorie diet with increased physical activity. Both groups complete assessments at the start of the study and again after three months. At each visit, participants have their weight, body composition, blood pressure, and resting metabolic rate measured. A blood draw is collected to evaluate cholesterol, blood sugar, insulin, appetite hormones, and liver and kidney function markers, and to analyze gene activity (RNA sequencing) and metabolites, which are small molecules that reflect how the body is using energy and nutrients. Participants also complete online questionnaires about diet, disordered eating, stress, mental health, and quality of life. Those in the lifestyle group attend three individual nutrition and physical activity counseling sessions over the course of the study. The main goals of the study are (1) to determine whether GLP-1 receptor agonist medication or lifestyle changes produce greater improvements in heart and metabolic health markers over three months; (2) to examine if GLP-1 receptor agonist medication or lifestyle changes produce greater improvement in disordered eating, stress, mental health, and quality of life; (3) to investigate if GLP-1 receptor agonist medication or lifestyle changes produce greater improvement in appetite-related hormones (i.e., ghrelin, GLP-1, insulin, leptin, and peptide YY); and (4) to explore whether the two approaches cause different changes in gene expression and metabolic profiles. This is a pilot study conducted at Texas Tech University's Nutrition and Metabolic Health Initiative clinic in Lubbock, Texas. Who can participate: Adults aged 18 years and older with a BMI of 27.5 or higher who are either starting semaglutide or tirzepatide therapy for weight management or who are seeking weight management without the use of weight-loss medications. Who cannot participate: Individuals who are pregnant or lactating, have a pacemaker or internal medical device, have certain serious medical conditions (such as active cancer, uncontrolled hypertension, or severe kidney disease), have type 1 diabetes, or use insulin for type 2 diabetes.

Detailed description

This prospective non-randomized comparative pilot study is conducted at the Nutrition and Metabolic Health Initiative (NMHI) clinic at Texas Tech University in Lubbock, Texas. The study includes two arms: a GLP-1 receptor agonist (GLP-1 RA) arm and a lifestyle (LS) comparator arm. GLP-1 RA arm participants are recruited from obesity medicine and aesthetics clinics in Lubbock, Texas, and enrolled within 0 to 3 days of initiating semaglutide or tirzepatide as prescribed by their own medical provider. LS comparator arm participants are recruited from the community via flyers, community events, hospital intranet postings, and university listservs; they will receive a structured behavioral intervention at no cost.

Each arm follows a two-visit assessment schedule at baseline and at three months. In-person visits include anthropometric measurement, bioelectrical impedance analysis for body composition, resting metabolic rate assessment via MedGem indirect calorimetry, blood pressure measurement (average of two readings after a five-minute rest), and venipuncture for biological sample collection. Blood is drawn into serum-separating tubes and an EDTA tube. Serum is processed for lipid panels, basal metabolic panels, hepatic and renal function markers including alanine aminotransferase, aspartate aminotransferase, total bilirubin, and creatinine, as well as appetite-related hormones including ghrelin, GLP-1, insulin, leptin, and peptide YY. The EDTA tube is processed for whole-blood RNA sequencing and untargeted metabolomics. Participants also wear a Garmin device for two weeks following the baseline visit to monitor sleep, heart rate, and oxygen saturation. Online questionnaires are completed via Qualtrics prior to each in-person visit.

LS comparator participants receive three individual lifestyle education sessions across the study period: at baseline, at one month, and at two months. Sessions may be completed in person or via a HIPAA-secured video platform and last approximately 30 to 45 minutes each. Each participant's total energy expenditure (TEE) is estimated by multiplying measured resting metabolic rate by a physical activity factor. Participants are instructed to follow a 500 kilocalorie daily deficit from TEE and to accumulate 150 to 300 minutes of moderate-intensity physical activity per week. Meal plans are based on the Academy of Nutrition and Dietetics Nutrition Care Manual. Dietary and physical activity adherence is monitored using MyFitnessPal or a food journal, with records reviewed at each session.

Given the pilot nature of this study, the primary emphasis is on effect size estimation and variance characterization to inform future adequately powered trials rather than definitive hypothesis testing. For example, with 12 participants in the GLP-1 receptor agonist arm and 15 participants in the LS comparator arm, the study is powered to detect only large between-group differences in cardiometabolic outcomes. Transcriptomic and metabolomic findings should be interpreted as hypothesis-generating. IRB approval was obtained prior to study initiation (IRB Number: IRB2024-370).

Interventions

• Drug GLP-1 Receptor Agonist Therapy
  Participants receive semaglutide or tirzepatide as prescribed by their own medical provider prior to study enrollment. Dosing and titration followed the prescribing provider's clinical judgment and are not controlled by the study team. Both medications are GLP-1 receptor agonists approved for weight management and glycemic control; tirzepatide additionally acts on the glucose-dependent insulinotropic polypeptide (GIP) receptor.
• Behavioral Structured Lifestyle Intervention
  A reduced-calorie diet providing a 500 kcal daily deficit from individually calculated total energy expenditure, combined with a goal of 150 to 300 minutes of moderate-intensity physical activity per week. Total energy expenditure is estimated by multiplying each participant's measured resting metabolic rate (MedGem indirect calorimetry) by a standard physical activity factor. Meal plans are based on the Academy of Nutrition and Dietetics Nutrition Care Manual. Three individual counseling sessio

Primary outcome measures

• Change in Fasting Blood Glucose [Time frame: Baseline and 3 months]
• Change in LDL Cholesterol [Time frame: Baseline and 3 months]
• Change in Triglycerides [Time frame: Baseline and 3 months]
• Change in Fasting Insulin [Time frame: Baseline and 3 months]
• Change in Blood Pressure [Time frame: Baseline and 3 months]
• Change in Disordered Eating [Time frame: Baseline and 3 months]
• Change in Food Addiction [Time frame: Baseline and 3 months]
• Change in Alcohol Use [Time frame: Time Frame: Baseline and 3 months]
• Change in Substance Use [Time frame: Time Frame: Baseline and 3 months]
• Change in Depressive Symptoms and Suicidal Ideation [Time frame: Time Frame: Baseline and 3 months]

Secondary outcome measures (9)

• Differential Gene Expression Profiles [Time frame: Baseline and 3 months]
• Change in Plasma Metabolomic Signatures [Time frame: Baseline and 3 months]
• Association Between Gene Expression Changes and Cardiometabolic Outcome Changes [Time frame: Baseline and 3 months]
• Change in Dietary Intake [Time frame: Baseline and 3 months]
• Change in Physical Activity [Time frame: Baseline and 3 months]
• Change in Sleep Duration [Time frame: Baseline and 3 months]
• Change in Health-Related Quality of Life [Time frame: Baseline and 3 months]
• Change in Liver Enzymes [Time frame: Baseline and 3 months]
• Change in Renal and Hepatic Markers [Time frame: Baseline and 3 months]

Eligibility criteria

Inclusion criteria

• Age 18 years or older
• BMI of 27.5 kg/m2 or higher
• For GLP-1 RA arm: initiating semaglutide or tirzepatide for weight loss as prescribed by their own medical provider
• For LS comparator arm: not currently taking a GLP-1 receptor agonist or other weight-loss medication, and no use of weight-loss medication within the past 3 months

Exclusion criteria

• Pregnant
• Breastfeeding
• Wears a pacemaker or other internal medical device
• Chronic kidney disease in the past 2 years
• Active cancer or cancer treatment within the past 6 months
• Current diagnosis of any major endocrine, inflammatory, cardiovascular, or neurological disorder/condition, including Addison's disease, autism, congestive heart failure, Crohn's disease, Cushing's syndrome, hyperparathyroidism, multiple sclerosis, neuromuscular disorders (Guillain-Barre syndrome or myasthenia gravis), stroke, thyroid gland disorders (hyperthyroidism or hypothyroidism), type 1 diabetes, and ulcerative colitis
• Insulin therapy for type 2 diabetes
• For LS comparator arm only: initiating any weight-loss medication (including a GLP-1 receptor agonist) currently or within the past 3 months

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Non-randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Other

Study locations

United States · 1 center

• Nutrition Metabolic Health Initiative (NMHI) — Lubbock

Identifiers

NCT: NCT07740291 · IRB2024-370

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗