Body Composition Changes After Initiation of GLP-1 Receptor Agonists in Adults With Obesity or Type 2 Diabetes

Inclusion Criteria:

1. Agrees to participate in the study by signing informed consent
2. Age 18 years or older
3. Diagnosis of obesity and/or type 2 diabetes mellitus, documented in the clinical record
4. Receiving, on indication of the treating physician and as part of routine clinical care, a therapy with activity on the GLP-1 receptor, including a) GLP-1 receptor monoagonists, b) dual GIP/GLP-1 coagonists, or c) other multiple coagonists with activity on the GLP-1 receptor holding current health authorization for clinical use in Mexico
5. Meeting one of the following conditions at the time of recruitment: a) starting an eligible therapy during the recruitment period, or b) being in an active dose titration phase, with an upward dose escalation documented by the treating physician, even if treatment started four or more weeks earlier, provided the participant has not yet reached a stable maintenance dose
6. Willingness and ability to attend follow up evaluations at 24 weeks (plus or minus 3 weeks) and 52 weeks (plus or minus 6 weeks)

Exclusion Criteria:

1. Diagnosis of type 1 diabetes or other specific forms of diabetes
2. Pregnancy or breastfeeding at the time of recruitment
3. Conditions that limit adequate measurement of body composition by DXA, including body weight above the equipment's technical limit of 159 kg, the presence of metallic devices or materials that interfere with the measurement, or having undergone a radiologic contrast study within the 7 days before the evaluation
4. Acute illness at the time of recruitment that could interfere with the study evaluations or with longitudinal follow up, including hospitalization within the 4 weeks before the baseline visit, active pneumonia, acute COVID-19 infection, diabetic ketoacidosis, or major surgery within the 6 weeks before recruitment
5. Chronic diseases or conditions associated with severe alterations in body composition, such as active cancer, active systemic inflammatory disease, advanced heart failure, or kidney disease on replacement therapy
6. Current or recent use, within 3 months, of systemic corticosteroids at chronic pharmacologic doses or medications with a direct modulating effect on muscle mass
7. Current or recent use, within 3 months before the index date, of weight loss medications other than GLP-1RA, such as phentermine, topiramate, or naltrexone/bupropion
8. Simultaneous participation in a double blind randomized clinical trial