Two-Year Weight Loss With GLP-1 Medications Compared With Sleeve Gastrectomy in Adults With Obesity (GLP-BARI-VAN)

Adults aged 18 years or older starting a GLP-1 receptor agonist, such as liraglutide or semaglutide, for weight management as part of routine clinical care. Participants will be followed prospectively for 24 months, with assessments at baseline and months 1, 3, 6, 12, and 24. Weight changes, medication use, treatment adherence, adverse events, and treatment discontinuation will be recorded. Medication selection and dosing will be determined by the treating clinician independently of study participation.

GLP-1 receptor agonists, such as liraglutide or semaglutide, prescribed for weight management as part of routine clinical care. Medication selection, dose escalation, dose adjustment, and treatment discontinuation are determined by the treating clinician and are not assigned by the study protocol. Medication use, weight changes, treatment adherence, and adverse events will be recorded during 24 months of prospective follow-up.

• Glucagon-Like Peptide-1 Receptor Agonist Therapy

Adults who underwent primary laparoscopic sleeve gastrectomy for obesity at the same center between January 1, 2020, and January 1, 2026, and were aged 18 years or older at surgery. Existing medical records will be reviewed retrospectively for baseline characteristics, postoperative weight measurements through 24 months, and surgical complications. This cohort will be matched with the GLP-1 receptor agonist cohort using propensity scores based on pretreatment characteristics. Surgery was performed as part of routine clinical care independently of this study.

Primary laparoscopic sleeve gastrectomy performed for obesity as part of routine clinical care between January 1, 2020, and January 1, 2026. The procedure involves removing a large portion of the stomach to create a narrow, sleeve-shaped stomach. Existing medical records will be reviewed retrospectively to assess weight changes and surgical complications through 24 months after surgery.

Percentage of total body weight loss (%TWL), calculated as [(baseline body weight - body weight at 24 months) / baseline body weight] × 100. Baseline is the date of GLP-1 receptor agonist treatment initiation or sleeve gastrectomy. The outcome will be compared between the propensity score-matched treatment cohorts.

Percentage of total body weight loss (%TWL), calculated as [(baseline body weight - follow-up body weight) / baseline body weight] × 100, compared between the treatment cohorts.

Change in body weight from baseline, measured in kilograms, compared between the treatment cohorts.

Change in body mass index (BMI) from baseline, calculated as body weight in kilograms divided by height in meters squared, compared between the treatment cohorts.

Percentage of participants losing at least 5% of their baseline body weight, compared between the treatment cohorts.

Percentage of participants losing at least 10% of their baseline body weight, compared between the treatment cohorts.

Percentage of participants losing at least 15% of their baseline body weight, compared between the treatment cohorts.

Percentage of participants losing at least 20% of their baseline body weight, compared between the treatment cohorts.

Percentage of participants losing at least 25% of their baseline body weight, compared between the treatment cohorts.

Percentage of participants in the GLP-1 receptor agonist cohort experiencing at least one adverse event. Event type, onset, severity, and suspected relationship to medication will be recorded.

Percentage of participants in the GLP-1 receptor agonist cohort experiencing gastrointestinal adverse events, including nausea, vomiting, diarrhea, constipation, abdominal pain, or reflux/dyspepsia.

Percentage of participants in the GLP-1 receptor agonist cohort experiencing an adverse event resulting in death, a life-threatening condition, inpatient hospitalization or prolonged hospitalization, persistent or significant disability, a congenital anomaly, or another medically important event.

Percentage of participants in the GLP-1 receptor agonist cohort whose medication dose is reduced because of an adverse event.

Percentage of participants in the GLP-1 receptor agonist cohort who permanently discontinue medication because of an adverse event.

Percentage of participants in the GLP-1 receptor agonist cohort who permanently discontinue medication for any reason. Reasons for discontinuation will be recorded.

Time in months from GLP-1 receptor agonist treatment initiation to permanent discontinuation. Participants without permanent discontinuation will be censored at their last known follow-up or the end of the 24-month observation period.

Percentage of participants with improvement or remission of baseline obesity-related comorbidities, including type 2 diabetes, hypertension, and dyslipidemia, assessed separately for each condition using available clinical records, laboratory results, and medication changes.

Percentage of participants with at least one emergency department visit during follow-up, assessed in each treatment cohort using available records.

Percentage of participants with at least one hospital admission during follow-up, excluding the index admission for sleeve gastrectomy, assessed in each treatment cohort using available records.

Percentage of participants in the sleeve gastrectomy cohort experiencing a complication within 30 days after surgery, including bleeding, staple-line leak, or complications requiring reoperation. Complications will be graded using the Clavien-Dindo classification when sufficient information is available.

Percentage of participants in the sleeve gastrectomy cohort experiencing complications more than 30 days after surgery, including stenosis, gastroesophageal reflux, nutritional deficiencies, or complications requiring revision surgery, as documented in available records.