Effects of Very Low-calorie Diet Versus Bariatric Surgery on Body Composition and Gut Microbiota Pattern

Study Overview
=================
Brief Summary
-----------------
Obesity is a chronic disease characterized by the excessive accumulation of fat in body and it continues to be a major public health problem worldwide. Treatment options for obesity include lifestyle modification, pharmacotherapy and bariatric surgery. Bariatric surgery is a highly effective treatment for obesity and results in rapid and sustained weight loss. Also, it significantly alters gut microbiota composition and function. A very low-calorie diet (VLCD) is a rapid weight loss program which calorie intake is severely restricted (< 800 kcal/day). It has been shown to be very effective to induce rapid weight loss and result in comorbidities resolution similar to bariatric surgery. Therefore, this study was aimed to study the effects of 12-week VLCD compare to bariatric surgery (Laparoscopic Roux-en-Y gastric bypass (LRYGB) or Laparoscopic Sleeve Gastrectomy (LSG)) on weight loss, body composition, gut microbiota pattern and other metabolic parameters.

Detailed Description
-----------------
The study will include obese patients (body mass index; BMI ≥ 37.5 kg/m2 or BMI ≥ 32.5 kg/m2 with comorbidities), aged 15-65 years at Ramathibodi Hospital, Thailand. The VLCD group will received total diet replacement for 12 weeks and the bariatric surgery group will undergo LRYGB or LSG. Study participants in both groups will be matched according to their age, sex, body mass index (BMI) and diabetic status. Body weight reduction and body composition, gut microbiota pattern, liver stiffness and steatosis, glycemic and other metabolic parameters (glucose, insulin, c-peptide, lipid profile, liver function test, kidney function test, complete blood count, electrolyte blood test, thyroid function tests, serum ketone and adiponectin), health-related quality of life, depression score and twenty-four-hour diet recall and physical activity will be assessed at baseline and at month 1, 3, 6, 9 and 12.

Official Title
-----------------
Effects of Very Low-calorie Diet Versus Bariatric Surgery on Body Composition and Gut Microbiota Pattern in Obese Patients

Conditions
-----------------
Obesity

Intervention / Treatment
-----------------
* Other: Very low-calorie diet
* Procedure: Bariatric surgery


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Aged 15-65 years Male or female Body mass index ≥ 32.5 kg/m2 with obesity related co-morbidity Body mass index ≥ 37.5 kg/m2 with or without an obesity related co-morbidity Exclusion Criteria: End stage disease such as cancer, cirrhosis Child-Pugh C, critical/acute illness Type 1 diabetes mellitus Recent eGFR < 30 ml/min/1.73 m2 Weight loss ≥ 5% in the previous 3 months Use of antibiotics in the previous 1 month Use of probiotic or prebiotic supplement in form of tablet or sachet in the previous 14 days Current treatment with anti-obesity drugs Pregnancy or breast feeding Substance abuse Uncontrolled psychiatric disorder and eating order History of allergy to any components in meal replacement product or whey protein product Unable to give informed consent

Ages Eligible for Study
-----------------
Minimum Age: 15 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Three groups of patients will be recruited at obesity clinic, Ramathibodi Hospital Mahidol University, Bangkok, Thailand. One group will take part in the very low-calorie diet (VLCD). One group will be undergone bariatric surgery (LRYGB or LSG)
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Very low-calorie diet<br>Patients in the very low-calorie diet group will be prescribed a very low-calorie diet (meal replacement) for 12 weeks, then the patients will be monitored up to 1 year | Other: Very low-calorie diet<br>* Meal replacement (800 kcal/day, protein 90 g/day)<br>|
| Experimental: Bariatric surgery<br>Patients in the bariatric surgery group will be undergone bariatric surgery LRYGB and will be follow-up according the current guideline | Procedure: Bariatric surgery<br>* Bariatric surgery will be performed by single surgeon at Ramathibodi Hospital Mahidol University, Thailand. Postoperative diet progression according to the current guideline will be prescribed from early post-op period to 1 year after surgery<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in body weight | Weight in kg | From baseline to 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body Composition | The percentage of body fat and skeleton muscle mass | From baseline to 12 weeks | 
| Gut microbiota pattern | Measured by 16S ribosomal RNA (rRNA) gene sequencing on the fecal samples | From baseline to 12 weeks | 
| Liver stiffness | Measured by FibroScan® instrument | From baseline to 12 weeks | 
| Liver steatosis | Measured by FibroScan® instrument | From baseline to 12 weeks | 
| Blood pressure | Systolic and diastolic blood pressure | From baseline to 12 weeks | 
| Fasting plasma glucose | Measured in mg/dl | From baseline to 12 weeks | 
| Hemoglobin A1c | Measured in % | From baseline to 12 weeks | 
| Fasting insulin | Measured in μIU/l | From baseline to 12 weeks | 
| Insulin resistance | Measured by the homeostatic model of insulin resistance (HOMA-IR) | From baseline to 12 weeks | 
| Triglyceride | Measured in mg/dl | From baseline to 12 weeks | 
| Total cholesterol | Measured in mg/dl | From baseline to 12 weeks | 
| LDL-cholesterol | Measured in mg/dl | From baseline to 12 weeks | 
| HDL-cholesterol | Measured in mg/dl | From baseline to 12 weeks | 
| Health-related quality of life | Measured by the EQ-5D-5L questionnaire | From baseline to 12 weeks | 
| Depression | Measured by the PHQ-9 questionnaire | From baseline to 12 weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Very low-calorie diet, Bariatric surgery, Body composition, Gut microbiota pattern