Gastric Bypass, adjustable gastric Banding or Sleeve gastrectomy surgery to treat severe and complex obesity: a multi-centre randomised controlled trial


The By-Band-Sleeve study is in follow up and is no longer recruiting new participants 


For more information on By Band Sleeve please visit our dedicated website:- By Band Sleeve home page.

Funder: NIHR/HTA

Sponsor: University of Bristol

REC number: 11/SW/0248

Status: In Follow Up

Obesity is an increasing health problem in the UK. Current national guidelines recommend that surgery is considered for people with severe and complex obesity. This surgery is known as bariatric surgery. Three of the most common types of bariatric surgery operations are: the adjustable gastric band (‘Band’), the Roux-en-Y gastric bypass (‘Bypass’), and the gastric sleeve (‘Sleeve’). At the moment, health professionals do not know which of these three operations is the most effective for long-term weight loss and improvement of health problems and quality of life.

The By-Band-Sleeve study is aiming to compare the three different types of operations to find out which is most effective. The results of this study will be used to improve the information available to people considering bariatric surgery in the future, which will help with decision-making between health professionals and patients. The results will also be used to inform NHS commissioners about the most effective and cost-effective operation.

The By-Band-Sleeve Study is currently in follow-up at twelve hospitals: University Hospitals Dorset NHS Foundation Trust (Bournemouth), St James University Hospital (Leeds), University Hospital Southampton, City Hospitals Sunderland NHS Foundation Trust, Somerset NHS Foundation Trust (Taunton), Royal Cornwall Hospitals NHS Trust (Truro), Heartlands Hospital (Birmingham), Portsmouth Hospitals University NHS Trust, University Hospitals of Derby and Burton NHS Foundation Trust, North Bristol NHS Trust, Homerton Hospital (London) and Imperial College Healthcare NHS Trust (London).

The study is coordinated from the BRI Hub of the Bristol Trials Centre at the University of Bristol. The study is funded by the National Institute for Health Research Health Technology Assessment Programme (ref: 09/127/53).

The By Band Sleeve Study has a sub-study called The Metabolomics Study which is currently in follow-up at seven hospitals: University Hospital Southampton, Somerset NHS Foundation Trust (Taunton), Royal Cornwall Hospitals NHS Trust (Truro), Heartlands Hospital (Birmingham), Portsmouth Hospitals University NHS Trust, North Bristol NHS Trust and Homerton Hospital (London). This study is due to end in March 2023. Patients who have been recruited and have attended their baseline (pre-surgery) appointment can be expected to be contacted to attend their follow-up appointment one year after their surgery or by March 2023, whichever is sooner. Patients who have been recruited but did not manage to attend their baseline appointment before their surgery will not be followed up. The study is led by Professor Nic Timpson and coordinated by Dr Laura Corbin both of whom are based in the Bristol Medical School, University of Bristol. The study is funded by the Wellcome Trust (ref: 202802/Z/16/Z).

For more information on the Metabolomics sub-study and to find out about eligibility please visit this web page:

NIHR Award Information

Contact Information

Chief Investigator: Professor Jane Blazeby

Study coordinator: Dr Graziella Mazza



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