The PREBA Study: Effect of Preoperative Weight Loss With a 14-day Low-calorie Diet on Surgical Procedure and Outcomes in Patients Undergoing RYGB Surgery

Study Overview
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Brief Summary
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Bariatric guidelines recommend preoperative weight loss of 5% to reduce the risk of surgical complications. However, results in the literature on the improvement of surgical procedure and outcomes are still conflicting. This study aims to evaluate the effect of preoperative weight loss by means of a 14-day low-calorie diet in bariatric patients on operative time, the ease of the Roux-en-Y gastric bypass (RYGB) procedure and long-term weight loss in a real-life experimental setting.

Official Title
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The PREBA Study: Effect of Preoperative Weight Loss With a 14-day Low-calorie Diet on Surgical Procedure and Outcomes in Patients Undergoing RYGB Surgery

Conditions
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Bariatric Surgery, Morbid Obesity

Intervention / Treatment
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* Other: 14-day Low Calorie Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Undergoing primary RYGB surgery (meeting all criteria + approval of surgeon) Able to prepare the meal replacements at home Exclusion Criteria: Undergoing another bariatric procedure than primary RYGB. Diabetes Mellitus Contraindication for the usage of Modifast meal replacements: Allergy or intolerance to any substance in the used meal replacements (Soy, milk, gluten, egg, peanuts, nuts and seeds) Veganism Kidney failure (GFR < 90 ml/min/1.73m2), liver failure or cardiac insufficiency A heart attack (myocardial infarct) in the past twelve months Cancer Hypokalaemia: serum potassium level <3.4 mmol/l Phenylketonuria & Porphyria

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention group<br>Participants in the intervention group will follow a low-calorie diet during 14 days before undergoing surgery. The diet will consist of both meal replacements and regular foods. For women, the diet provides ± 900 kcal, 50 grams of carbohydrates, 85 grams of protein, 30 grams of fat and 25 grams of fibres. For men, the diet provides ± 1000 kcal, 55 grams of carbohydrates, 100 grams of protein, 30 grams of fat and 30 grams of fibres. | Other: 14-day Low Calorie Diet<br>* Participants will be asked to: Use 4 (women) or 5 (men) Modifast meal replacements per day. Daily consume a minimum of 250 grams of (raw) vegetables without dressing. Daily consume 100 grams of lean meat/fish/meat analogues. Daily consume two spoons of liquid oil Daily drink at least 2.0 litres of water, coffee or tea without added sugar or milk, bouillon or sugar-free drinks.<br>|
| No Intervention: Control group<br>Participants in the control group can eat according to the standard nutritional advices provided by their dietitian. These advices are intended to educate participants on the recommended eating pattern after surgery. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Operative time of the RYGB procedure | Duration of the surgical procedure, retrieved from the electronic medical record | surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ease of the RYGB procedure | Ten aspects of the RYGB procedure will be scored on a 5-point Likert scale. The total score can range from 10 to 50, with 10 being the easiest. The ten aspects include: Exerting force on instruments (1=very low, 5= very high) Difficulty of moving the liver (1=very easy, 5=very difficult) Size of the liver (1=very small, 5= very large) Size of omentum (1=very small, 5= very large) Difficulty of approaching pouch (1=very easy, 5=very difficult) Accessibility of Treitz ligament (1=very easy, 5=very difficult) Difficulty of creating pouch (1=very easy, 5=very difficult) Difficulty of measuring small intestine (1=very easy, 5=very difficult) Difficulty of entero-entero connection (1=very easy, 5=very difficult) Difficulty of abdominal wall hernia repair (1=very easy, 5=very difficult) | surgery | 
| Appearance of the patient's liver | Includes four images of the liver in different stages (1= healthy, 2= fatty liver, 3= fatty liver with inflammation, 4= liver cirrhosis). Surgeons will be asked to choose the image that best matches the appearance of the patient's liver. | surgery | 
| Post-operative weight loss | Body weight measurements to assess weight loss after surgery | 4 weeks, 3, 6 months and 1, 2, 3, 4, 5 years after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Morbid Obesity, Bariatric surgery, Weight Loss, Diet, RYGB