Core Outcome Measures in Effectiveness Trials

Development of a core outcome set for bariatric surgery

General Information

Bariatric surgery is increasingly being viewed as a solution to weight loss, particularly for those who are morbidly obese and this is supported by current NICE guidance. Morbid obesity affects over 2% or 1.2 million people in the UK, and it is not known what is the best operation for weight loss surgery. Current outcome reporting in bariatric surgery has a high degree of heterogeneity and a lack of standardized definitions for outcomes and adverse events. The recent UK NIHR Health Technology Assessment into the clinical effectiveness and cost effectiveness of bariatric surgery for obesity identified problems with outcome reporting as one of the most common limitations in the literature because there were often differences in the outcome measures reported by the studies and suggested that a core set of important adverse outcomes of bariatric surgery be identified so that a standardised approach to describing adverse outcomes can be developed.

The development of a core outcome set will be valuable for clinical trials in bariatric surgery because it will reduce reporting bias, create homogeneity in outcome reporting, improve meta-analyses and ensure that only evidence based outcomes with high validity and reliability are reported. A core outcome set can also improve the quality of reporting in non-randomised studies and clinical audit because this will also allow data synthesis and comparison between hospitals and centres. This project will develop a core outcome set for use in surgical trials and clinical audit in bariatric surgery.

Mr James Hopkins 1
Prof Jane Blazeby 2,3 Principle investigator

On Behalf of the BYBAND Trial Management Committee:
Professor Barney Reeves 4, Mr Richard Welbourn 5, Professor Jenny Donovan 2,
Dr Chris Rogers 4, Dr Robert Andrews 5, Dr Sarah Wordsworth 6, Mr James Byrne 7, Professor Janice Thompson 8, Professor Paul Roderick 9, Mrs Janet Edmond - Trustee, British Obesity Surgery Patient Association.

1 University Surgical Unit, University of Southampton, UK
2 School of Social and Community Medicine, University of Bristol, Bristol, UK
3 University Hospitals Bristol NHS Foundation Trust, Bristol, UK
4 Clinical Trials and Evaluation Unit, School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, UK
5 Taunton and Somerset NHS Trust, Taunton, Somerset, UK
6 Health Economic Research Centre, Department of Public Health, University of Oxford, Oxford, UK
7 Southampton University Hospitals NHS Trust, UK
8 University of Birmingham, Birmingham, UK
9 University of Southampton, Southampton, UK


Further Study Information

October 2011 - August 2015
Funding source(s):
HTA Clinical Trials and Evaluation Board (BY-BAND trial)

Health Area

Disease Category
Endocrine & metabolic

Disease Name
Diabetes mellitus

Target Population

Age Range
16 - 100


Nature / type of Intervention


Consensus meeting
Delphi process
Systematic review

Three stages of work will be undertaken
i) systematic reviews of the clinical outcomes in reported trial literature for bariatric surgery to identify comprehensive list of potential clinical outcomes, using the 2009 HTA review and an up-to-date literature search from 2008-2011.

ii) This will be used to produce a questionnaire which will be sent to survey approximately 200 key stakeholders (clinicians, and allied health professionals) using at least 2 rounds of the Delphi methodology to refine the core outcomes

iii) consensus meetings with key stakeholders to consider the processes, results and potential core outcomes.

Will involve:
Bariatric Surgeons
Bariatric Clinical Nurse Specialists
Bariatric Dieticians
Bariatric Physicians and Endocrinologists
Anaesthetists with an interest in bariatric surgery

Stakeholders Involved

Clinical experts

Study Type

COS for clinical trials or clinical research

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