Background
NICE have recently published two documents describing the use of disease-specific reference models in economic evaluations(1) and the specific scope for a reference case extension for obesity(2).
The scope for the obesity extension covers technologies for the management of overweight or obesity for adults and reduction of weight-related comorbidities. People with and without pre-existing weight-related comorbidities, such as type 2 diabetes and cardiovascular disease, are included. The reference case extension will not cover: the prevention of overweight or obesity in people of normal weight; treatment of overweight or obesity in children.
Aim of this report
To review the existing COMET database entries for relevant obesity COS in terms of the core outcomes included, noting the quality of the COS development process.
Methods
We reviewed the existing COMET database entries for relevant obesity COS in terms of the core outcomes included, noting the quality of the COS development process. We extracted data on the scope, methods and participating stakeholder groups. The quality of the COS development process was assessed using the Core Outcome Set-STAndards for Development (COS-STAD ) criteria(3). Core outcomes were extracted from each COS and classified according to the outcome taxonomy developed by Dodd et al(4).
Results
The search identified eight eligible published obesity COS. Five COS were developed for use in clinical trials, two COS for use in clinical practice and one for an international registry. Applicable interventions included bariatric surgery (n=3), drugs (n=1), self-management (n=1), exercise (n=1), behavioural weight management (n=1), and any intervention (n=1).
We found methodological quality varied substantially across the eight obesity COS. Taking account of the COS-STAD assessments and the participant numbers, we concluded that the COS developed by Coulman et al.(5) was methodologically sound, meeting 10* of the 12 COS-STAD criteria, and with a good number of participants with lived experience throughout the process. This COS was developed for clinical trials of metabolic and bariatric surgery interventions however, with the authors recommending general and intervention-specific outcomes.
Across the eight COS, there are three outcomes recommended in the majority for measurement in obesity research and/or clinical practice, all of which are included in the Coulman et al. COS:
(i) Weight, with specified definitions/measures including weight change and waist circumference.
(ii) Cardiovascular disease/risk, as defined by blood pressure, glucose levels, lipids, hepatic parameters, and renal function.
(iii) Quality of life, with specified measurement instruments including the EQ-5D-5L and the OBESI-Q.
Conclusions
We recommend from this review of COS that the common core outcome domains of weight, cardiovascular risk and quality of life be included in the obesity reference model case extension.
The COMET database also includes multiple published and ongoing COS relating to type 2 diabetes. Some of these COS may also be relevant to the obesity reference model case extension, thus there is a need to specify the scope to identify which COS may be most appropriate. One example is the SCORE-IT COS, which established consensus on the most important outcomes for non-surgical interventions for hyperglycemia in type 2 diabetes(6). Consensus was reached on 18 core outcomes across five domains, which included outcomes relating to diabetes care, quality of life and long-term diabetes-related complications.
References
(1) Publication of NICE position statement: Use of disease-specific reference models in economic evaluations: https://www.nice.org.uk/corporate/ecd18/chapter/references
(2) Publication of Obesity reference case extension scope: https://www.nice.org.uk/guidance/gid-pmg10019/documents/final-scope
(3) Kirkham JJ, et al. PLoS Med. 2017;14(11): e1002447. doi: 10.1371/journal.pmed.1002447
(4) Dodd S, et al. J Clin Epi. 2018;96:84-92. doi: 10.1016/j.jclinepi.2017.12.020.
(5) Coulman KD, et al. PLoS Med. 2016;13(11):e1002187. doi: 10.1371/journal.pmed.1002187.
(6) Harman NL, et al. BMJ Open Diab Res Care. 2019;7:e000700. doi:10.1136/bmjdrc-2019-000700
Sarah Gorst, Susanna Dodd, Samuel Lucas, Paula Williamson (COMET Initiative, Department of Health Data Science, University of Liverpool)
Disease Category: Endocrine & metabolic
Disease Name: Obesity
Age Range: 18 - 120
Sex: Either
Nature of Intervention: Any
- Study investigators
- Systematic review of core outcome sets
- Recommendations made
- Literature review