Bariatric surgery is the most clinically effective treatment for people with severe and complex obesity. There are several different types of surgery - sleeve gastrectomy and Roux-en-Y gastric bypass are the most common with gastric band decreasing in recent years, and one-anastomosis gastric bypass gaining in popularity. Published studies in this area differ in the outcomes reported, and how they are defined and measured, making comparison between studies challenging. The development of a core outcome set for use in effectiveness trials of bariatric surgery, was previously developed to address these issues.
Large, prospectively collected, registries can play an important part in understanding outcomes of surgery. The availability of a vast amount of data from a large number of patients who have undergone the bariatric procedures is a valuable source. These data can be used to examine disease epidemiology, treatment effectiveness and the quality of patient care. There are currently 18 national bariatric surgery registries, however not all have been developed with key variables defined from the outset. As with published research studies in this area, variables measured in different registries, vary considerably between countries, making international comparisons problematic. Initial work by the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) to set up a global registry project to allow for comparisons of obesity and bariatric surgery on an international level has been conducted. However, there is currently no agreement on the minimum data elements to include, including how to define and measure these.
The aim of this project was to develop a core set of data items for use in an international registry to improve data synthesis and reduce research waste in bariatric surgery.
Kerry Avery (PI),Jane Blazeby, Katy Chalmers, Karen Coulman and Dimitri Pournaras (University of Bristol)
John Dixon, Lilian Kow, Ronald Liem, Johan Ottosson, Richard Welbourn and Wendy Brown (on behalf of the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) committee)
Disease Category: Endocrine & metabolic
Disease Name: Obesity
Age Range: Unknown
Sex: Either
Nature of Intervention: Surgery
- Clinical experts
- Patient/ support group representatives
- COS for registry
- Consensus meeting
- Delphi process
- Interview
- Literature review
- Survey
- Systematic review
The study comprised three phases:
Phase 1: Development of the long list of items and questionnaire for a Delphi survey
A long list of potentially relevant items were taken from our published BARIACT project (three systematic reviews and qualitative interviews), the Dutch data dictionary project (collated items from 11 existing national bariatric registries) and systematic searches of bariatric surgery effectiveness trials covering the years 2013-2020. PPI group reviewed the long list for completeness.
Phase 2: Prioritisation of items in an international Delphi survey
Link to online surveys sent out to IFSO members which include a wide range of international clinical stakeholders. Participants were asked to rate importance of each survey item on a nine-point Likert scale. Proposed new items recommended by two or more participants in Round 1 were considered for inclusion in Round 2 by the study team. Those that answered at least one question of the Round 1 survey, were invited to complete Round 2. Round 2 feedback included their own individual Round 1 scores, plus scores of their peer group, all other health professionals (excluding their peer group), and of the whole group. Participants were asked to re-rate the items on the questionnaire, considering the Round 1 feedback.
Phase 3: Consensus meeting
Round 2 participants who expressed an interest in the consensus meeting, were invited. The consensus meeting was held over Zoom and chaired by an independent expert in core set development methodology with previous experience of running consensus meetings. Items were discussed in small breakout groups and discussed and voted on as a whole group, until the core data set was agreed upon.