9 Summary of the methods used to develop this guideline

Introduction

The reviews, expert reports 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 Public Health Advisory Committee (PHAC) meetings provide further detail about the Committee's interpretation of the evidence and development of the recommendations.

Guideline development

The stages involved in developing public health guidelines are outlined in the box below.

1. Draft scope released for consultation

2. Stakeholder comments used to revise the scope

3. Final scope and responses to comments published on website

4. Evidence reviews and economic modelling undertaken and submitted to PHAC

5. PHAC produces draft recommendations

6. Draft guideline (and evidence) released for consultation

7. PHAC amends recommendations

8. Final guideline published on website

9. Responses to comments published on website

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 PHAC to help develop the recommendations. The overarching questions were:

Question 1: Which mid‑life behavioural risk factors are associated with successful ageing and the primary prevention or delay of dementia, non‑communicable chronic conditions, frailty and disability? How strong are the associations? How does this vary for different subpopulations?

Question 2: What are the most effective and cost‑effective mid‑life interventions for increasing the adoption and continuation of healthy behaviours?

  • To what extent do the different health behaviours prevent or delay dementia?

  • To what extent do the different health behaviours prevent or delay frailty and disability related to modifiable behavioural risk factors?

  • To what extent do the different health behaviours prevent or delay non‑communicable chronic diseases?

Question 3: What are the key issues for people in mid‑life that prevent or limit their adoption and continuation of healthy behaviours, and to what extent do they have an effect? How does this differ for subpopulations, for example by ethnicity, socioeconomic status or gender?

Question 4: What are the most effective ways of delivering interventions that increase the adoption and continuation of healthy behaviours in mid‑life? For example, how do interventions targeting single versus multiple behaviours compare? How does effectiveness and cost effectiveness vary in relation to the recipient's demographic variables?

These questions were made more specific for each review.

Reviewing the evidence

Effectiveness reviews

One review of effectiveness and cost effectiveness was done.

  • Review 3. Effectiveness and cost‑effectiveness of mid‑life interventions for increasing the uptake and maintenance of healthy lifestyle behaviours and the prevention or delay of dementia, disability, frailty and non‑communicable chronic diseases related to modifiable lifestyle risk factors.

Identifying the evidence

Additional searches of electronic databases and the grey literature were carried for papers relevant to this review and also for the other 2 reviews.

The literature search for the effectiveness and cost‑effectiveness review was updated in March 2014.

Selection criteria

Studies were included in the effectiveness and cost‑effectiveness review if they focused on:

  • adults at mid‑life (aged 40–64 years for the general population or aged 18–39 in disadvantaged populations)

  • effectiveness and cost‑effectiveness outcomes for interventions to promote the uptake and maintenance of healthy behaviours that may have a positive effect on successful ageing or delay the start of dementia, disability and frailty and non‑communicable diseases.

Studies were excluded if:

  • they were not published in English

  • they were from non‑Organisation for Economic Co‑operation and Development (OECD) populations

  • they evaluated use of drugs and food supplements

  • they focused on the diagnosis and management of dementia, disability and frailty and common non‑communicable diseases, including management of obesity.

Inclusion and exclusion criteria for each review varied. See each review for details of the inclusion and exclusion criteria.

Other reviews

  • Review 1. Issues that prevent or limit the uptake and maintenance of healthy behaviours by people in mid‑life (barriers and facilitators)

  • Review 2. Behavioural risk factors in midlife associated with successful ageing and the primary prevention or delay of disability, dementia, frailty, and non‑communicable chronic conditions.

One in-house pragmatic review was done. See:

  • Review 4. Service delivery mid‑life

Identifying the evidence
Review 1 and 2

Several databases were searched in September 2013 for systematic reviews, interventional, observational and qualitative studies for review 1 and longitudinal cohort studies for review 2, dating from January 2000.

Review 4

A targeted and pragmatic approach was taken to identifying the evidence, using the call for evidence, a specific request to the PHAC developing this guideline, re‑screening of review 1 full text articles, and identification of previous reviews of healthy lifestyle programmes using in‑house expertise from developing previous NICE guidance. The date limit for including studies was 31 December 2013, apart from PHAC‑submitted studies, which were considered up to 21 February 2014. No limits on study type were imposed.

Selection criteria
Review 1 and 2

Studies were included in the reviews if they focused on:

  • adults at mid‑life (aged 40–64 years for the general population or aged 18–39 in disadvantaged populations).

Studies were excluded if:

  • they were not published in English

  • they focused on use of drugs and food supplements

  • they focused on the diagnosis and management of dementia, disability and frailty and common non‑communicable diseases, including management of obesity.

Review 4

Studies were included in the review if they focused on:

  • people aged 40–64 years. The age range was lowered to include people aged 18–39 for disadvantaged groups

  • evaluations of programmes that promote the uptake or maintenance of any programme that could be considered 'healthy lifestyle' delivered in a real‑world UK setting

  • provided a description of the service delivery factors that affected the uptake and maintenance of a programme, and other organisational factors such as staff and setting.

Studies were excluded if:

  • they reported on the effectiveness of an intervention or the barriers and facilitators without any clear discussion of service delivery

  • were done in a non‑UK setting.

Quality appraisal

Included papers for reviews 1–3 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. A tool specifically designed to assess the quality of systematic reviews (AMSTAR) was used for reviews 1 and 3. 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 guideline. Each evidence statement concludes with a statement of applicability (directly applicable, partially applicable, not applicable).

Studies included in review 4 were not quality assessed because of the type of studies included and the pragmatic real‑world nature of the review.

Summarising the evidence and making evidence statements

The review data were summarised in evidence tables (see the reviews in supporting evidence).

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 'Supporting evidence'). 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.

Cost effectiveness

There was a review of economic evaluations and an economic modelling exercise. See review 3 and 'Cost‑effectiveness of interventions aimed at increasing physical activity to prevent the onset of dementia'.

Economic modelling

Assumptions were made that could underestimate or overestimate the cost effectiveness of the interventions (see review modelling report for further details).

An economic model was constructed to incorporate data from the reviews of effectiveness and cost effectiveness. The results are reported in: cost-effectiveness of interventions aimed at increasing physical activity to prevent the onset of dementia.

How the PHAC formulated the recommendations

At its meetings in April and May 2104, the Public Health Advisory Committee (PHAC) considered the evidence, expert reports and cost effectiveness to determine:

  • whether there was sufficient evidence (in terms of strength and applicability) to form a judgement

  • where relevant, whether (on balance) the evidence demonstrates that the intervention, programme or activity can be effective or is inconclusive

  • where relevant, the typical size of effect

  • whether the evidence is applicable to the target groups and context covered by the guideline.

The PHAC developed recommendations through informal consensus, based on the following criteria:

  • Strength (type, quality, quantity and consistency) of the evidence.

  • The applicability of the evidence to the populations/settings referred to in the scope.

  • Effect size and potential impact on the target population's health.

  • Impact on inequalities in health between different groups of the population.

  • Equality and diversity legislation.

  • Ethical issues and social value judgements.

  • Cost effectiveness (for the NHS and other public sector organisations).

  • Balance of harms and benefits.

  • Ease of implementation and any anticipated changes in practice.

Where possible, recommendations were linked to evidence statements (see the evidence for details). Where a recommendation was inferred from the evidence, this was indicated by the reference 'IDE' (inference derived from the evidence).

  • National Institute for Health and Care Excellence (NICE)