Guidance
7 Summary of the methods used to develop this guidance
7 Summary of the methods used to develop this guidance
Introduction
The reviews, commissioned report and economic modelling report include full details of the methods used to select the evidence (including search strategies), assess its quality and summarise it.
The minutes of the Programme Development Group (PDG) meetings provide further detail about the Group's interpretation of the evidence and development of the recommendations.
All supporting documents are listed in About this guidance.
Key questions
The key questions were established as part of the scope. They formed the starting point for the reviews of evidence and were used by the PDG to help develop the recommendations. The overarching questions were:
How effective and cost effective are lifestyle weight management programmes in helping overweight or obese children and young people to achieve and maintain a healthy weight?
What are the essential components of an effective and cost-effective weight management programme for overweight and obese children and young people?
The subsidiary questions were:
1. How does effectiveness and cost effectiveness vary for different population groups? (Examples may include children and young people from different black and minority ethnic groups, from low-income groups, of different ages or genders, or with special needs.)
2. What are the most effective and cost-effective ways of addressing and sustaining behavioural change among overweight and obese children and young people using community-based weight management programmes?
3. How does the inclusion of parents, carers and the wider family impact on the effectiveness of community-based weight management programmes for children and young people?
4. What barriers and facilitators affect the delivery of effective weight management programmes for children and young people and how do they vary for different population groups?
5. What are the views, perceptions and beliefs of the children, young people and their families who use weight management services?
6. What are the views, perceptions and beliefs of the staff responsible for commissioning and delivering weight management services to children and young people?
7. How can more overweight and obese children and young people be encouraged to join, and adhere to, lifestyle weight management programmes?
These questions were made more specific for each evidence review.
Reviewing the evidence
Effectiveness reviews
One review of effectiveness and cost effectiveness was conducted (Review 1).
Identifying the evidence
A number of databases were searched in May 2012 for relevant studies published in English from January 2000. See the review for details of the databases searched.
In addition, randomised controlled trials (RCTs), economic evaluations and views studies published between 1990 and 1999 were identified and included using 'snowballing' methods. (Systematic reviews, reference list checking and citation tracking were 'unpicked' from the Scopus and Science Citation Index databases.)
NICE also issued a call for evidence from registered stakeholders in May 2012.
Selection criteria
Studies were included in the effectiveness and cost-effectiveness review if they:
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covered children and young people aged below 18 years who were overweight or obese, or their parents, carers and families
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considered lifestyle weight management programmes for obese and overweight children and young people that focus on diet, physical activity or behaviour change, or any combination of these factors
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measured changes in weight, diet, physical activity, wellbeing or satisfaction with the service
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were carried out in the UK (any study design)
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were RCTs and quasi-RCTs (randomisation method unclear) of 100 or more participants from Australia, Canada, New Zealand, the US and other western European countries
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reported health economic outcomes.
Studies were excluded if they:
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focused on young women under 18 who were pregnant
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were RCTs involving a population of less than 40
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focused on clinical treatment of obesity.
Other reviews
One review of barriers and facilitators to implementing lifestyle weight management programmes for children and young people was conducted (review 2).
Selection criteria
Studies were included in the review if they:
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considered lifestyle weight management programmes for obese and overweight children and young people that focused on diet, physical activity or behaviour change, or any combination of these factors
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were qualitative, survey and other observational studies of the barriers and facilitators to delivering such interventions or the views, perceptions and beliefs of those using and delivering them
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were conducted in Australia, Canada, New Zealand, the US or western Europe
Studies were excluded if they:
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focused on young women under 18 who were pregnant
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focused on clinical treatment of obesity
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reported intrapersonal barriers and facilitators to losing or managing weight not associated with the participation in, or delivery of, weight management programmes
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were quantitative studies that did not measure attitudes (for example, correlation studies).
Quality appraisal
Included papers were assessed for methodological rigour and quality using the NICE methodology checklist, as set out in Methods for the development of NICE public health guidance. Each study was graded (++, +, −) to reflect the risk of potential bias arising from its design and execution.
Study quality
++ All or most of the checklist criteria have been fulfilled. Where they have not been fulfilled, the conclusions are very unlikely to alter.
+ Some of the checklist criteria have been fulfilled. Those criteria that have not been fulfilled or not adequately described are unlikely to alter the conclusions.
− Few or no checklist criteria have been fulfilled. The conclusions of the study are likely or very likely to alter.
The evidence was also assessed for its applicability to the areas (populations, settings, interventions) covered by the scope of the guidance. Each evidence statement concludes with a statement of applicability (directly applicable, partially applicable, not applicable).
Summarising the evidence and making evidence statements
The review data were summarised in evidence tables (see full reviews).
The findings from the reviews and expert reports were synthesised and used as the basis for a number of evidence statements relating to each key question. The evidence statements were prepared by the external contractors (see About this guidance). The statements reflect their judgement of the strength (quality, quantity and consistency) of evidence and its applicability to the populations and settings in the scope.
Commissioned report
A short report was commissioned on practical and process issues related to the provision of lifestyle weight management services for children and young people. It synthesised responses to a questionnaire submitted by service providers. See the commissioned report on practical and process issues in the provision of lifestyle weight management services for children and young people.
Cost effectiveness
The existing cost-effectiveness evidence was reviewed as part of evidence review 1: effectiveness and cost effectiveness of lifestyle weight management services for children and young people.
In addition, an economic model was constructed. The results are reported in: Managing overweight and obesity among children: report on economic modelling and cost consequence analysis. This was produced by M Brown, T Marsh, K Rtveladze (all from the UK Health Forum, formerly the National Heart Forum) and R Fordham, M Suhrcke, D Turner, R Little and O Filani (all from the University of East Anglia).
How the PDG formulated the recommendations
At its meetings in July, October and December 2012 and January, February and July 2013, the Programme Development Group (PDG) considered the evidence, expert reports and cost effectiveness to determine:
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whether there was sufficient evidence (in terms of strength and applicability) to form a judgement
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where relevant, whether (on balance) the evidence demonstrates that the intervention or programme/activity can be effective or is inconclusive
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where relevant, the typical size of effect (where there is one)
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whether the evidence is applicable to the target groups and context covered by the guidance.
The PDG developed recommendations through informal consensus, based on the following criteria:
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Strength (type, quality, quantity and consistency) of the evidence.
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The applicability of the evidence to the populations/settings referred to in the scope.
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Effect size and potential impact on the target population's health.
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Impact on inequalities in health between different groups of the population.
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Equality and diversity legislation.
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Ethical issues and social value judgements.
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Cost effectiveness (for the NHS and other public sector organisations).
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Balance of harms and benefits.
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Ease of implementation and any anticipated changes in practice.
Where possible, recommendations were linked to an evidence statement(s) (see the evidence section for details). Where a recommendation was inferred from the evidence, this was indicated by the reference 'IDE' (inference derived from the evidence).