Can Pre-operative Lean Mass Predict Weight Loss After Roux-en-Y Gastric Bypass?

NCT07565051 | Recruiting DMC

• 1 other identifier: 2024-02136
• Study Type: observational
• Target: 91
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this observational study is to evaluate whether preoperative fat-free mass predicts post-operative weight loss in patients undergoing Roux-En-Y gastric bypass. The primary objective of this study is to evaluate whether preoperative fat-free mass predicts weight loss in the two years following RYGB. We will collect the following data, assessed as part of routine follow-up:

• height, weight, hip and waist circumferences
• body composition by bioimpedance analysis and dual energy-X-ray absorptiometry
• Muscle strength and physical activity
• Nutritional parameters: resting energy expenditure, eating behavior and digestive tolerance", plasma micronutrient status. .
• Cardiovascular risk factors: fasting glucose, blood levels of Hb1Ac, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, blood pressure
• Co-morbidities: joint pain and arthritis, sleep apnea, gastro-oesophageal reflux, metabolic dysfunction-associated fatty liver disease (MAFLD), cancer, stroke, heart attack. Quality of life: quality of life by the "Bariatric Analysis and Reporting Outcome (BAROS) questionnaire", symptoms of dumping syndrome by the "Sigstad diagnostic score system" Birthdate, birthweight and term of their children

Conditions

Morbid Obesity Requiring Bariatric Surgery

Keywords

obesity; gastric bypass; body composition; bone mineral density; handgrip strength; sarcopenic obesity

Outcome Measures

Primary Outcomes (2)

• Correlation between Fat-free mass (FFM) and weight loss following RYGB

  FFM and lean body mass measurement using BIA and DXA, respectively

  2 years

• Evolution of body composition in the two years after bariatric surgery

  Measurments of body composition by dual energy X-ray absorptiometry before gastric bypass and yearly after gastric bypass

  5 years

Study Arms (1)

Patients with scheduled RYGB at the Geneva University Hospitals

Morbidly obese patients scheduled for Roux-en-Y gastric bypass

Eligibility Criteria

• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

Patients with scheduled gastric bypass at the Geneva University Hospitals (HUG)

You may qualify if:

• Patients ≥ 18 years AND
• Scheduled RYGB at the HUG OR previous RYGB at the HUG with a present follow-up in Clinical Nutrition and dietetics at the HUG AND
• Understanding French

You may not qualify if:

• Inability or refusal to give consent.
• Planification for another type of bariatric surgery than RYGB
• Contra-indications to bariatric surgery as stated under www.smob.ch: insufficient nutritional knowledge in nutrition to lose weight, pregnancy, kidney failure (Creatinine ≥ 300 umol/l without dialysis, Crohn's disease, active cancer or remission \< 2 years, active psychiatric disease, substance abuse (alcohol, cannabis, opioids), absence of compliance, lack of understanding of the requirements and necessary lifestyle changes reported by physician or dietician.

Sponsors & Collaborators

• University Hospital, Geneva: lead

Study Sites (1)

Geneva University Hospitals

Geneva, Canton of Geneva, 1205, Switzerland

RECRUITING

Biospecimen

Retention: SAMPLES WITHOUT DNA

Blood biobank and gastric and intestinal tissue biobank

MeSH Terms

Conditions

Obesity

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Laurence Genton, MD

CONTACT

0041 79 553 34 84; laurence.genton@hug.ch

Laure Wilmart-Beck

CONTACT

0041 22 372 93 49; laure.wilmart@hug.ch

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: OTHER
• Target Duration: 5 Years
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: April 27, 2026
• First Posted: May 4, 2026
• Study Start: August 18, 2025
• Primary Completion (Estimated): August 18, 2027
• Study Completion (Estimated): August 18, 2032
• Last Updated: May 4, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)