7 Summary of the methods used to develop this guidance

Introduction

The reviews, primary research, commissioned 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 Interventions Advisory Committee (PHIAC) meetings provide further detail about the Committee's interpretation of the evidence and development of the recommendations.

All supporting documents are listed in About this guidance.

Guidance development

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

1. Draft scope released for consultation

2. Stakeholder meeting about the draft scope

3. Stakeholder comments used to revise the scope

4. Final scope and responses to comments published on website

5. Evidence reviews and economic modelling undertaken and submitted to PHIAC

6. PHIAC produces draft recommendations

7. Draft guidance (and evidence) released for consultation and for field testing

8. PHIAC amends recommendations

9. Final guidance published on website

10. 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 PHIAC to help develop the recommendations. The overarching questions were

  • Question 1: What types of brief advice are effective and cost effective in promoting physical activity in primary care? Does the method of delivery, type of advice and person delivering the advice influence the effectiveness and/or cost effectiveness of the intervention?

  • Question 2: What type of local infrastructure and systems support effective and cost effective delivery of brief advice on physical activity in primary care?

  • Question 3: What are the barriers to, and facilitators for, the delivery of brief advice on physical activity in primary care?

  • Question 4: What are the barriers to, and facilitators for, the uptake of brief advice on physical activity in primary care?

The subsidiary questions were:

1. What types of advice are given in the intervention?

2. What is the diversity of the population (for example, in terms of age, gender or ethnicity)?

3. What is the status of the person delivering the intervention and how is it delivered?

4. What are the content, frequency, length and duration of the intervention?

5. Under what circumstances are interventions delivered?

6. Are there any adverse or unintended effects?

7. What are the patient/public views of brief advice interventions offered in primary care to promote physical activity?

8. What are practitioner or expert views of brief advice interventions offered in primary care to promote physical activity?

9. What is the role of infrastructure and systems in facilitating interventions?

These questions were made more specific for each review (see reviews for further details).

Reviewing the evidence

Effectiveness and barriers and facilitators mixed methods review

This review consisted of 2 components:

  • Component 1 (Effectiveness) examined the effectiveness of brief advice in increasing physical activity in adults aged 19 and over. It also examined the effect of infrastructure and systems on increasing the delivery of brief advice.

  • Component 2 (Barriers and facilitators) examined and identified factors that impact on the delivery and uptake of brief advice from both practitioner and patient perspectives.

The 2 components are presented in 1 report 'Physical activity: brief advice for adults in primary care'.

Identifying the evidence

A number of databases were searched in March 2012 for intervention studies and quantitative and qualitative evidence on barriers and facilitators, from 1990 to 2012. See the review for details of the databases searched.

An initial search strategy was developed that included using categories of key words and subject terms. A focused search strategy of free text and subject heading terms was used, building on the search strategy for brief advice developed by the NICE Public Health Collaborating Centre for Physical Activity (2006). Terms were identified using concepts derived from the guidance scope.

Further iterations of this search strategy were developed based on the subsequent identification of relevant records. Iterations were repeated as new concepts were identified, within the time frame of the study.

Selection criteria

Studies were included in the review if:

  • They covered adults aged 19 years and over. Papers with varying ages were considered provided the focus of the research was adults and not children or adolescents. Participating providers include all health professionals who are responsible for delivering primary care and including, but not restricted to, all those listed as examples in the scope (community nurses, GPs, health visitors, pharmacists, physiotherapists, exercise professionals, health trainers).

  • They covered brief advice to promote physical activity.

  • They considered either brief advice intervention effectiveness from patient and/or practitioner perspectives and/or barriers and facilitators to the delivery and/or uptake of brief advice from patient and/or practitioner perspectives.

Studies were excluded if:

  • They covered children and young people aged 18 years and under.

  • Interventions were offered outside of primary care or were not delivered by a primary care professional.

  • Interventions were tailored for individuals with specific medical conditions (but not excluding interventions for individuals with risk factors for chronic conditions, for example hypertension, impaired glucose tolerance, obesity).

  • They covered exercise referral schemes offering an assessment of need, development of a tailored physical activity programme, monitoring and follow-up (see Four commonly used methods to increase physical activity, NICE public health guidance 2 for a recommendation on exercise referral).

  • They covered schemes that encourage physical activity – for example walking and cycling schemes (see Walking and cycling, NICE public health guidance 41).

As the review was a mixed methods review containing both effectiveness and barriers and facilitators components, the inclusion and exclusion criteria for each review varied and details can be found at 'Physical activity: brief advice for adults in primary care'.

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

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 was summarised in evidence tables (see full reviews).

The findings from the review 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/public health collaborating centres (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.

Cost effectiveness

There was a review of economic evaluations and an economic modelling exercise.

Review of economic evaluations

A database search strategy for MEDLINE and EMBASE was developed using the search strategy for the effectiveness review that had been developed by the effectiveness review team and agreed with NICE. Search terms derived from NHS EED (a database of economic evaluations) were added to identify papers relevant to the economic evaluation.

Further search strategies for additional databases specific to the economic evidence review were adapted from terms used in the MEDLINE and EMBASE strategies. Searches were limited to papers reported in English and published between 1990 and March/April 2012.

Studies were included if they focused on 'full economic evaluations' (that consider costs and health/non-health consequences) of relevant types of intervention or scheme, and high quality costing studies conducted in the UK or OECD countries. Studies were excluded if they focused on burden of disease and non-comparative costing studies, or other studies which do not involve assessing the cost and related benefits/effectiveness of relevant interventions. Studies were categorised according to study type and methodological rigour and quality. Quality ratings for studies are:

++ 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.

Review of economic barriers and facilitators

The search strategy for the economic barriers and facilitators review was based on past search strategies and studies around demand for physical activity (Anokye 2010; Harland et al. 1999) in conjunction with the search strategy developed for the effectiveness review. The search for evidence was based on 10 electronic databases, additional papers supplied by NICE and the effectiveness review team, a call for evidence distributed by NICE, a Google Scholar search of citations and a search of 6 organisational websites. Searches were limited to papers reported in English and published between 1990 and March/April 2012.

Studies were included if they covered:

  • Quantitative estimates of the statistical association (for example, correlation or regression coefficient) between uptake of/adherence to brief advice interventions and economic variables such as income, employment status, demographics, money/time costs, tastes and preferences.

  • Qualitative data (for example, focus groups and interviews with brief intervention participants) about the economic factors relating to uptake of and adherence to brief interventions.

Studies were excluded if they did not involve examining the barriers to uptake and delivery of relevant interventions, or studies that were not conducted in the UK or OECD countries. Quality ratings of included studies were undertaken as per methods outlined by NICE (2009) 'Methods for the development of NICE public health guidance' (second edition).

Economic modelling

A number of assumptions were made which 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.

A Markov model considered a cohort of sedentary, healthy individuals over their remaining lifetime to estimate the costs and benefits of a cohort exposed to brief advice (in the first year of cycle only) compared with a cohort not exposed to brief advice (usual care).

People exposed to brief advice were assumed to have a greater probability of becoming 'physically active'. States were defined in line with existing evidence on the relative risks for developing coronary heart disease (both non-fatal and fatal), or stroke (both non-fatal and fatal), or type 2 diabetes.

The analysis adopted a lifetime horizon, an NHS/Personal Social Service perspective and discounted quality-adjusted life years (QALY) as a key outcome.

A series of sensitivity analyses was undertaken to explore the potential effects of study design and risk of bias on pooled outcomes. In addition, cost-consequence analysis was performed to include a broader range of benefits and dis-benefits associated with brief advice and physical activity. This used data from the cost-utility model, effectiveness review and an update of the previous literature search.

The results are reported in the economic modelling report.

How PHIAC formulated the recommendations

At its meetings in September 2012 the Public Health Interventions Advisory Committee (PHIAC) considered the evidence 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 or programme/activity can be effective or is inconclusive

  • where relevant, the typical size of effect (where there is one)

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

PHIAC developed draft 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 an evidence statement(s) (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)