Longitudinal Phenotyping of Bariatric Surgery Patients

Recent studies have shown that bacteria within the gut play an important role in diabetes improvement after bariatric (weight-loss) surgery. Bariatric surgery fundamentally changes the environment within the gut, which results in changes to the makeup of the trillions of bacteria living within it. These changes in the gut bacteria can affect the body in a number of complex ways, which we are only just beginning to understand. For example, gut bacteria breakdown food we are unable to absorb ourselves, leading to altered sugar levels and can release molecules that act to reduce appetite.

In this study we aim to find out how bariatric surgery changes the gut bacteria and how this leads to weight loss and improvement of diabetes. With this understanding we hope to discover potential targets for future treatments, such as identifying beneficial bacteria that could be supplemented with probiotics in patients.

Additionally, although highly successful, up to 30% of obese patients do not undergo improvement of their diabetes after bariatric surgery. We aim to identify molecules within the patient's blood or urine that are able to predict the likely chance a patient will undergo improvement in their diabetes after bariatric surgery to help clinicians select patients most likely to benefit.

Study Overview

• Status: Completed
• Conditions: Obesity; Diabetes Mellitus, Type 2
• Intervention / Treatment: Procedure: Laparoscopic Roux-en-Y Gastric Bypass; Procedure: Laparoscopic Sleeve Gastrectomy

Detailed Description

This study aims to assess how the gut microbiome affects the host phenotype following bariatric surgery through altered gut microbiome-host co-metabolism. The secondary objective is to identify novel biomarkers for the preoperative prognostication of T2DM remission following bariatric surgery.

The study will longitudinally phenotype obese diabetics and non-diabetics undergoing Roux-en-Y Gastric Bypass or Sleeve Gastrectomy surgery. Patients will be assessed preoperatively and at 3 months and 1 year postoperatively. Clinical measures recorded will include; 1) anthropometric & physiological measurements, 2) demographic details, 3) biochemical parameters including HbA1c, 4) anti-hyperglycaemic and other medication use, 5) co-morbidity status and 6) dietary choices through 24hr dietary recall questionnaires.

Blood, urine and stool samples will be collected at the above time points. Changes to the microbiome will be assessed using metagenomic sequencing. Global metabonomic profiles of serum, urine and faecal water will be generated using 1H-NMR. Further targeted analyses of bile acid and short-chain fatty acid profiles will be performed using LC-MS / GC-MS.

The study will utilise multivariate statistical analysis techniques to identify metabolic pathways altered following intervention, and novel host-microbiome co-metabolism pathways that impact upon phenotype. A supervised multivariate analysis, mapping T2DM outcomes to metagenomic and metabonomic data will be performed with the aim of identifying novel preoperative biomarkers that are able to prognosticate T2DM resolution following bariatric surgery.

• Study Type: Observational
• Enrollment (Actual): 158

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, W2 1NY
    • Imperial Weight Centre

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Participants with obesity undergoing bariatric surgery

Description

Inclusion Criteria:

• Obese (BMI>30kg/m2)
• Type 2 Diabetes Mellitus and non-diabetic
• Failure of efforts at lifestyle modification and dieting
• Fitness for anaesthesia and procedure
• Willingness to comply with the trial protocol

Exclusion Criteria:

• Previous bariatric surgery
• Pregnancy or intention to become pregnant during trial period
• Lack of capacity to consent
• Previous major abdominal surgery (Small or large bowel resection, stomach, liver, pancreatic or splenic surgery. Does not include patients who have previously had an appendicectomy, cholecystectomy or hernia repair).

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Group 1; Roux-en-Y Gastric Bypass	Procedure: Laparoscopic Roux-en-Y Gastric Bypass
Group 2; Sleeve Gastrectomy	Procedure: Laparoscopic Sleeve Gastrectomy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Complete Diabetes Remission at 3 Months	Participants with HbA1c <6% (42mmol/mol), off anti-diabetic medication, at 3 months	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Partial Diabetes Remission	HbA1c <6.5% (48mmol/mol), off anti-diabetic medication, at 3 months. (Includes participants with complete remission).	3 months
HbA1c Improvement	Reduction in HbA1c at 3 months	3 months
Weight Loss	Weight loss at 3 months	3 months
BMI Reduction	BMI reduction at 3 months	3 months
Complete Diabetes Remission	HbA1c <6% (42mmol/mol), off anti-diabetic medication, at 1 year	1 year
Partial Diabetes Remission	HbA1c <6.5% (48mmol/mol), off anti-diabetic medication, at 1 year. (Includes participants with complete diabetes remission).	1 year
HbA1c Improvement	Reduction in HbA1c at 1 year	1 year
Weight Loss	Weight loss at 1 year	1 year
BMI Reduction	BMI reduction at 1 year	1 year

Collaborators and Investigators

• Sponsor: Imperial College London
• Investigators: Principal Investigator: Ara Darzi, MB, BCh, MD, Imperial College London

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2015
• Primary Completion (Actual): February 1, 2019
• Study Completion (Actual): February 1, 2019

Study Registration Dates

• First Submitted: April 15, 2015
• First Submitted That Met QC Criteria: April 15, 2015
• First Posted (Estimate): April 20, 2015

Study Record Updates

• Last Update Posted (Actual): November 6, 2020
• Last Update Submitted That Met QC Criteria: October 15, 2020
• Last Verified: October 1, 2020

More Information

Terms related to this study

• Keywords: Bariatric Surgery; Sleeve Gastrectomy; Gastric Bypass; Gastroplasty
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Diabetes Mellitus; Diabetes Mellitus, Type 2
• Other Study ID Numbers: 15SM2479