Metabolic and Bariatric Surgery

This prospective, observational cohort study aims to evaluate whether the use of collagen-containing supplements is associated with differences in muscle mass, body composition, and body image among patients who have undergone sleeve gastrectomy (SG). The study will be conducted at the General Surgery outpatient clinic of a private hospital in Bursa, Türkiye, between May 2026 and March 2027, and will enroll adult patients (aged 18-65 years) who meet current ASMBS/IFSO eligibility criteria for metabolic and bariatric surgery. Participants will be naturally allocated into two observational groups based on their own choice to use or not use collagen-containing supplements; no supplement will be provided or recommended by the study team, and no intervention will be made to participants' standard clinical care. All patients will be followed according to routine clinical practice preoperatively and at 2 weeks, 1 month, 3 months, and 6 months postoperatively. Primary outcome measures include anthropometric parameters (body weight, BMI, fat mass, fat mass percentage, fat-free mass, muscle mass, percentage of weight loss, percentage of excess weight loss, waist and hip circumference) assessed via bioelectrical impedance analysis (Tanita MC-780 MA), and body image assessed using the Turkish-validated Body Shape Questionnaire (BSQ). Secondary outcomes include biochemical parameters, comorbidities, and macronutrient intake data obtained from 3-day dietary records analyzed using the BEBİS nutrition software. The study hypothesizes that patients using collagen-containing supplements will show significant differences in muscle mass and body composition parameters compared with non-users, and that supplement use will be significantly associated with BSQ scores. A sample size of approximately 52 participants per group was calculated using G\*Power 3.1 (one-way ANOVA, Cohen's f = 0.25, α = 0.05, power = 0.80).

This is a Phase 3a, randomized, parallel-controlled trial designed to compare the early re-initiation of semaglutide, starting two weeks after sleeve gastrectomy, to standard care (no pharmacotherapy following surgery). The trial will involve 150 youth with severe obesity who have been on semaglutide 2.4 mg weekly for at least 3 months prior to surgery. Participants will be randomized to either (1) semaglutide 2.4 mg weekly or (2) standard care for 24 months. Primary, secondary, and tertiary outcomes will be assessed at multiple time points: 1-month, day of surgery, and 1-, 3-, 6-, 9-, 12-, 18-, and 24-months postoperatively. We hypothesize that early re-initiation of semaglutide will be safe, well-tolerated, and lead to greater improvements in obesity, cardiometabolic risk, and eating behaviors.

One Anastomosis Gastric Bypass (OAGB) is the most common metabolic and bariatric surgery (MBS) in Israel, recognized for its effectiveness in achieving sustainable weight loss and mitigating obesity-related diseases. The metabolic outcomes of OAGB are significantly influenced by the length of the biliopancreatic limb (BPL). The objective of this study is to determine whether tailoring the BPL length to the total small bowel length (TSBL) results in more effective weight loss compared to patients undergoing OAGB with a fixed BPL of 180 cm. Efficacy and safety of this approach will also be evaluated, ensuring it does not lead to long-term morbidity or negatively impact patients' quality of life.