Development of a novel scalable behavioural weight loss maintenance programme
Some text in this section has been reproduced with permission from Richards et al.62 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) licence, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.
This WP developed an acceptance-based guided self-help programme to support weight loss maintenance.
Rationale
The long-term health impact and cost-effectiveness of weight loss interventions depends on the maintenance of weight lost. In WP1.1, we showed that extended use of programmes using traditional behavioural strategies can reduce post-treatment weight regain to some extent. However, we also showed that weight regain is commonplace and that alternative approaches are needed to better address the psychological challenges of weight loss maintenance.
We identified third-wave cognitive–behavioural therapies, particularly acceptance and commitment therapy (ACT), as a potential strategy to address key psychological challenges and improve long-term weight management.42 However, these interventions are typically delivered face-to-face by psychologists, which limits their scalability and increases cost. The objective of this WP was to develop a ACT-based guided self-help intervention for weight loss maintenance that uses digital technology and guidance from non-specialists to enable delivery at scale.
Methods
The intervention development process is described in detail in Richards et al.62
We were guided by the Medical Research Council (MRC) framework for the development of complex interventions in health care,63,64 the Intervention Mapping Protocol,65 and the person-based approach for enhancing the acceptability and feasibility of interventions.66 We established a stakeholder panel consisting of two commissioners of diabetes and weight management services (one local authority, one Clinical Commissioning Group), a public health nutritionist, a dietitian, a diabetes educator, a general practitioner (GP), a diabetes nurse, a practice nurse and a clinical psychologist. We also established a patient user group panel (PUGP) of people who had previously lost weight, either as part of a BWMP or self-guided, and who were trying to keep that weight off. We held a series of group meetings with both panels to develop a deeper understanding of their needs, to support interpretation of the primary research we conducted, and to review plans and prototypes throughout the intervention development process. If panel members were unable to attend group meetings, we arranged 1 : 1 or telephone meetings. During workshops, panel members reviewed and fed back on evidence synthesis, new evidence, theoretical modelling and intervention content. Where appropriate, feedback was incorporated into revised materials and any changes (or decisions not to make changes) were discussed at subsequent workshops.
Phase 1: collation and analysis of new and existing evidence
In phase 1, we collated and analysed existing evidence syntheses of qualitative studies of weight loss maintenance,50 theories of behaviour change maintenance,67 determinants of weight loss maintenance68 and effectiveness of weight loss maintenance interventions.40 We also conducted new research to fill evidence gaps we identified:
Systematic review and network meta-analysis of third-wave cognitive–behavioural therapies for weight management
Full details of this new evidence synthesis are published in Lawlor et al.42
We originally intended to update previous systematic reviews on mindfulness- and acceptance-based interventions for weight management. However, previous reviews had a number of substantial methodological limitations, including searching a limited number of databases and not using a comprehensive search strategy. We conducted a comprehensive systematic review and network meta-analysis that synthesised existing evidence on the effect of third-wave cognitive–behavioural therapy for weight management on weight, psychological and physical health outcomes in adults with overweight and obesity.
Using pairwise random-effects meta-analysis, we found moderate to high quality evidence that these third-wave cognitive–behavioural interventions achieved small improvements in weight loss at 12- and 24-month follow-up compared to programmes using standard behavioural approaches and no or minimal interventions, although third-wave approaches were not consistently better at shorter follow-up times (< 9 months). We undertook network meta-analysis to compare different types of third-wave interventions that had not been compared in head-to-head trials. We identified ACT-based interventions as having the most consistent evidence of effectiveness: they achieved greater weight loss than standard behavioural approaches at 12 and 24 months, were ranked the best intervention up to 12 months and were the only third-wave interventions to have outcomes ≥ 24 months. Meta-regression did not identify any specific intervention characteristics (dose, duration, mode of delivery) associated with better outcomes. Findings supported our decision to incorporate acceptance-based weight management strategies into our weight loss maintenance intervention and confirmed the absence of existing studies that had used ACT-based programmes specifically for weight loss maintenance that are delivered remotely using digital technology and non-specialists.
Qualitative study of cognitive and behavioural strategies to overcome lapses and prevent relapse in weight loss maintenance
Our qualitative study comparing the experiences of weight loss maintainers and regainers from the WRAP trial were summarised in WP1.1 and published in Lawlor et al.52 From this work, we identified that a weight loss maintenance programme should include specific strategies for planning for high-risk situations and managing interpersonal relationships in the context of food.
Modelling of a justifiable cost for weight loss maintenance programme (work package 2.3)
We used the NIHR SPHR Diabetes Prevention Model to estimate the maximum justifiable cost of a weight loss maintenance intervention given an estimated intervention effect and a specified ICER. Full details of this work are described under WP2.3 and published in full in Bates et al.69
Assuming a 1.5 kg difference between groups at 12 months and a cost-effectiveness threshold of £20,000 per QALY, we estimated that the justifiable cost of an intervention ranged from £26 to £204. This supported our decision to focus on remote intervention delivery to keep costs low and gave us a ‘budget’ to aim for.
Phase 2: theoretical modelling and intervention development
Phase 2 included the iterative development of guiding principles, a logic model, and the intervention design and content.
Development of guiding principles
An initial logic model and set of guiding principles were developed based on the primary research outlined above and existing literature. These were further developed through workshops with the stakeholder panel and the PUGP.
Content development
An outline of the intervention structure and a plan for the wire frame of the platform were developed by the research team and the software developers, based on the guiding principles. These were reviewed at meetings of the patient user group and the stakeholder panel. Intervention content and website structure were revised based on this feedback.
The research team then drafted intervention content based on the guiding principles and drawing on published protocols and manuals for acceptance-based interventions. The software developers created a wireframe for the intervention platform which the research team could add content to. An ‘alpha’ version of the web platform (including alpha versions of content for the first three modules) was tested using think aloud protocols and home testing with our PUGP. We identified common themes in the feedback and held a focus group with the PUGP, the research team, and the software developers to discuss and agree what could/should be changed. Proposed changes were reviewed in relation to the extent to which they were important for behaviour change, consistent with guiding principles, uncontroversial and easy to implement, and repeated by more than one person.70 They were then categorised as ‘must have’, ‘should have’, ‘could have’ or ‘would have’.
Module content was revised based on think aloud protocols and panel feedback and the remaining modules were drafted. The research team worked with the PUGP and graphic designers to develop a logo and design elements for the website, and to procure audio visual content. The software developers revised the website functionality based on feedback and a beta version was released for a further round of think aloud protocols and home testing.
Results
The name of our intervention is SWiM, which stands for Supporting Weight Management. The content and structure of SWiM is described in detail in Richards et al.62 The ethos of SWiM is to use principles of ACT to help people who have lost weight to reflect on what has worked (and not worked) in the past, build on what works for them, and learn new strategies to overcome challenges that typically derail weight loss maintenance. The core of the intervention is delivered via a simple and engaging interactive web platform. There are weekly psychoeducational sessions (including reflexive exercises and behavioural experiments) for 13 weeks, followed by a 4-week break for participants to reflect and practice their new skills, and a final session at week 18. Participants also have four scheduled telephone contacts of about 30 minutes’ duration and three further optional calls with a coach. Coaches are trained non-specialists with equivalent qualifications and experience to a health trainer. They are trained to deliver manualised support with scripts/templates.
Strengths and limitations
The SWiM intervention was developed using a rigorous theory-, evidence- and person-based approach. There was strong involvement from people with lived experience of obesity who have previously completed BWMPs and attempted to manage their weight afterwards. It also incorporated views of service commissioners and health professionals with experience of supporting people with long-term weight management, who understand what is likely to be feasible and acceptable in an NHS or local authority context. While user testing was undertaken throughout the process, SWiM needs further evaluation to test feasibility.
Supporting Weight Management was also developed within the constraints of a limited (i.e. non-commercial) development budget. For example, it was deliberately not hard-wired as an app because of the high-associated costs and the need to make continuous changes to the content and structure in an agile way. There is also considerable compromise between evidence of what is likely to be most effective (e.g. lifelong intervention and in-person support) and what is affordable and likely to be cost-effective. The level of coach support we think is needed to be effective means this intervention is at the higher end of our estimated justifiable cost for a weight loss maintenance programme (WP2.3).
Conclusions
Our comprehensive intervention development process facilitated the creation of an intervention that is based on scientific theory and evidence for supporting people with weight loss maintenance and is grounded in the experiences of the target users and the context in which it is intended to be delivered. The intervention will be refined based on the findings of the feasibility study in WP2.2.
Interrelation with other work packages
Supporting Weight Management development was informed by qualitative research in WP1.1 and health economic modelling in WP2.3. The feasibility and acceptability of the intervention and the trial design were evaluated in WP2.2 and 2.3.