Title: (REBALANCE) REview of Behaviour And Lifestyle interventions for severe obesity: AN evidenCE synthesis
Funder: Chief Scientist Office, Scotland

Abstract: Background: Over BMI 35kg/m2 obesity co-morbidities and their economic consequences greatly increase. Systematic review (SR) evidence on the feasibility/acceptability, and (cost) effectiveness of weight management for BMI 35kg/m2 or more is lacking. Objective: To synthesise the quantitative, qualitative, and economic evidence; develop an economic model to inform weight management programmes for people with BMI 35kg/m2 or more. Design: 5 SRs on behavioural interventions, licensed pharmacotherapy, bariatric surgery weight loss/maintenance. SR1: long-term randomised controlled trials (RCTs); SR2: long-term UK studies; SR3: qualitative, mixed-methods research on patient/provider experiences; SR4: economic evaluations of interventions; SR5: long-term RCTs lifestyle versus bariatric surgery. Economic model (micro-simulation) to estimate long-term costs, outcomes and cost-effectiveness of promising interventions, lifestyle versus surgery. Innovative methods to identify effective intervention characteristics, control for variability in support given to comparator groups. Integrate findings in realist mixed-methods synthesis. Search strategy: SRs 1-5 (no language restrictions, studies from 1990): Medline, Embase, Cinahl, CCTR, DARE, Psycinfo, NHS EED, SSCI. Contact professional, health and commercial organisations for unpublished studies; study authors for detailed descriptions of intervention and comparator group support, qualitative and process outcomes, outcome data clarification. Research strategy: SR1-2,5:outcomes are weight, cardiometabolic risk factors, disease outcomes, adverse events, quality of life. Study quality using Cochrane risk of bias and checklist used for NICE reviews. Intervention and comparator group support coded using the TIDieR, BCT (Behaviour Change Technique)-v1 taxonomy, Campbell and Cochrane Equity Methods Group checklist. Meta-analyses and (bivariate) mixed-effects meta-regression analyses to synthesise evidence and explore study, sample, intervention and comparator group characteristics associated with outcomes. SR3: feasibility and acceptability of interventions for participants and providers. Coding, thematic analysis of qualitative and mixed-methods research. Quality assessment of studies’ conceptual clarity and interpretative rigor. Comparison of patterns and associations for broader interpretative themes. SR4: costs, outcomes for interventions collected. Standard checklists assess quality of the economic evaluation. Economic model: data from SRs 1,2,4,5 used to populate the UK Health Forum “Obesity Micro-simulation Model”, estimating cost-effectiveness of most promising interventions, including bariatric surgery, NHS perspective. Integrate findings in realist mixed-methods synthesis. Expected outputs of research: Evidence to inform guidance on weight management programmes for people with BMI 35kg/m2 or more, and future research. At least 5 research papers; conference presentations; summaries for policy makers, professionals, patients, public; online videos and podcasts. Project timetable: Months 0-2: protocol, advisory meeting. Months 2-14: SR1,SR2,SR5. Months 9-14: SR3. Months 12-17: SR4, identification of data and population of health economic model. Months 15-17: complete analyses, synthesis of SR1-5 and economic model analysis. Months 18-20: advisory meeting, final report, all other outputs. Expertise: AA,PA: SRs of obesity treatments. GM,PA,MdB: coding, meta-analysing (behavioural) interventions, including comparator group variability in RCTs. DB,LW: economic modelling and evaluations. ZS,AA: mixed-methods synthesis.

Lay abstract: Obesity in adults increases the risk of many serious illnesses, such as type 2 diabetes, heart disease, osteoarthritis, breast and bowel cancer. People who are very heavy are at a higher risk of these diseases than people who are just a little bit overweight. Current weight loss services provided by the NHS, local authorities and commercial organisations rarely take the severity of people’s weight into account. So people who may need more support, or different kinds of support, to lose weight may not be offered more help, or that help for longer. There are some services already provided by the NHS to help people who are very heavy lose weight, but the provision of these services is patchy round the UK. The services provided are very variable, and it is not clear exactly how much of what kinds of help should be provided. We would like to review all the research evidence to see if weight loss programmes should be designed differently for people who are much heavier (and more likely to have medical problems related to their weight). We will particularly examine which weight loss programmes help people lose weight in the long term and keep that weight off. We will also look to see how weight loss programmes compare with weight loss surgery. We will look to see if these weight loss programmes decrease people’s risks from serious diseases, such as diabetes or heart disease. We will look at the evidence about where and how these services should be delivered to make them more attractive to people. We are interested in finding out how losing and then maintaining a healthier weight can be made more relevant for people's lives. We will also look to see if the best weight loss programmes provide good value for the NHS. We have many years of experience undertaking reviews on the management of obesity. No organisation that we know of is looking at the evidence in the way that we plan. The main costs of this project are for reviewers to find and bring together all the relevant evidence. Other costs are to cover the supervision of these reviewers and provide administrative support. We have requested funds to cover advisory meetings and teleconferences with lay representatives with experience of obesity, and policy makers from the NHS. Costs also include publication of five open access articles, which anyone will be able to read. We will present our findings at conferences for policy makers, providers of weight management services, researchers and the public.

Research activity codes: 6.6 PSYCHOLOGICAL AND BEHAVIOURAL
Health categories: CANCER AND NEOPLASMS;CARDIOVASCULAR;METABOLIC AND ENDOCRINE;ORAL AND GASTROINTESTINAL;STROKE