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Prevention and Control of Noncommunicable Diseases: Guidelines for Primary Health Care in Low Resource Settings. Geneva: World Health Organization; 2012.

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Prevention and Control of Noncommunicable Diseases: Guidelines for Primary Health Care in Low Resource Settings.

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3Methodology used to prepare the guideline

The WHO Guideline for Management of Asthma and COPD through a Primary Care Approach in Resource-constrained Settings was prepared according to the WHO Handbook for Guideline Development. The scope in the format of PICOT questions was defined by WHO and circulated to the guideline expert panel members for comments in advance of the guideline expert panel meeting (Annex 3).

The Cochrane Airways Group was consulted to design the search strategy for the finalized scoping questions. A methodologist was contracted to assess the quality of evidence using the Assessment of Multiple Systematic Reviews (AMSTAR) tool and to prepare evidence summaries according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. The AMSTAR instrument is a validated tool for critically appraising the methodological quality of systematic reviews. It consists of an 11-item questionnaire with each item receiving a score of 1 if the specific criterion was met or a score of 0 if the information was not reported or was unclear or the criterion was not applicable. After applying AMSTAR, the review that scored the highest was selected. Systematic reviews were assessed rather than single studies.

The evidence was assessed according to the GRADE methodology. In this system evidence is classified as high, moderate, low or very low and is defined as follows:

  • High: further research is very unlikely to change our confidence in the estimate of effect.
  • Moderate: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
  • Low: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
  • Very low: any estimate of effect is very uncertain.

Factors that were considered in classifying the evidence were: (i) the study design and rigour of its execution; (ii) the consistency of results and how well the evidence can be directly applied to patients; (iii) interventions; (iv) outcomes; and (v) comparator. Other important factors were whether the data were sparse or imprecise and whether there was potential for reporting bias.

The recommendations were drafted according to the GRADE methodology for assessing the quality of evidence and strength of recommendations. The guideline expert panel, comprising clinical experts and scientists in the area of CRDs, guideline methodology, research, pharmacology and policy-making, was convened on 20–21 December 2010 at WHO headquarters in Geneva (see the list of participants). The meeting was preceded by several teleconference discussions and e-mail consultations. The priority questions and scope of the guideline were discussed and finalized based on the comments provided by the expert panel members during these discussions preceding the meeting.

The guideline expert panel members were involved in the following:

  • advising on the priority of questions and scope of the guideline;
  • advising on the choice of important outcomes for decision-making;
  • commenting on the evidence used to inform the guideline;
  • advising on the interpretation of the evidence, with explicit consideration of the overall balance of risks and benefits of each particular intervention for asthma and COPD patients;
  • formulating recommendations, taking into account the scope of the guideline, its target audience and resource-constrained settings.

At the guideline expert panel meeting, the members were asked to identify critical clinical outcomes for the purposes of making the recommendations. The expert panel reviewed the available evidence summaries and made recommendations. All recommendations were based on consensus and in accordance with the assessed evidence.

All declarations of interests of the guideline expert panel members were reviewed before the guideline expert panel meeting. None of the members declared any potential conflict of interests relevant to the discussion and recommendations, either personal or institutional. The GRADE tables (Annex 4) were prepared by the members of the guideline expert panel and the methodologist.

Formulating the recommendations included explicit consideration of the quality of evidence, benefits, harms, burdens, costs and values, and preferences. Recommendations were classified as strong or weak, as recommended in the GRADE methodology.

For each recommendation, the final agreement was based on group consensus by the guideline expert panel members using a combination of the following factors:

  • evidence balanced for benefits/risks of the intervention;
  • costs, values and feasibility of each particular intervention in resource-constrained settings;
  • quality of evidence itself (high, moderate, low, very low);
  • preferences of the group based on clinical experience of the expert panel members.

Each recommendation was formulated only when full consensus was reached among the expert panel members based on all of the above-mentioned points. As a result, each recommendation was classified either as strong or weak according to the GRADE methodology.

Strong recommendations can be interpreted as:

  • most individuals should receive the intervention;
  • most well-informed individuals would want the recommended course of action and only a small proportion would not;
  • could unequivocally be used for policy-making.

Weak recommendations can be interpreted as:

  • majority of well-informed individuals would want the suggested course of action, but an appreciable proportion would not;
  • widely varying values and preferences;
  • policy-making will require extensive debates and involvement of many stakeholders.

After the guideline expert panel meeting, the WHO Secretariat revised the draft guideline according to the recommendations from the guideline expert panel. Comments are reviewed by the WHO Secretariat and are being incorporated into the final version.

Identification of important outcomes

Summaries of the best available evidence were prepared to inform scoping questions. A list of potential outcomes to be considered by the guideline expert panel was developed both for asthma and COPD scoping questions. The panel members ranked these outcomes and were requested to identify any relevant critical outcomes not included on the list. The panel members were also asked to identify which outcomes they felt were critical, important but not critical, and not important.

The panel members were then asked to score the outcomes, using numbers corresponding to the GRADE importance of outcomes where 7–9 indicated the outcome was critical for a decision, 4–6 indicated it was important, and 1–3 indicated it was not important. Both the average scores for each outcome and the range of scores were considered. The individual scores were discussed and disagreements were resolved by consensus. Outcomes were included roughly in order of their relative importance in the GRADE tables (Annex 4).

Outcomes (asthma)Outcomes (COPD)
MortalityMortality
Quality of life (QoL)Quality of life (QoL)
Mechanical ventilationBreathlessness
CoughCough
WheezeWheeze
DyspnoeaSputum production
Distance walkedDistance walked
Drop-outDrop-out
Adverse effectsSerious adverse events
PEFRPEFR
FEV1FEV1
FVCFVC

Search strategy, selection criteria, data collection and judgement

The search strategy was to identify systematic reviews relevant to the scoping questions. Once systematic reviews were identified, searches were also conducted for RCTs in order to identify any additional trials not included in the reviews. Summaries of all identified systematic reviews were shared with members of the guideline expert panel before the December 2011 meeting.

For systematic reviews, an advanced search with Medical Subject Headings (MeSH) was conducted. The comprehensive search strategies designed by the Cochrane Airways Group based on approved PICOT questions are described in Annex 5 (in addition, the Cochrane Airways Group Asthma and COPD registers of RCTs were searched). The limits that were applied to the search included: published in the last 10 years; human being only; English language; systematic reviews.

As a result of the AMSTAR quality assessment of the found systematic reviews, nine systematic reviews for asthma and 14 systematic reviews for COPD PICOT questions were selected (Annex 6).

Evidence profiles based on the systematic reviews were created using the GRADE methodology (Annex 4). Using this approach, assessments of the quality of evidence for each important outcome took into account the study design, limitations of the studies, consistency of the evidence across studies, directness of the evidence with respect to the populations, interventions and settings, and the precision of the summary estimate of effect. If there were several relevant systematic reviews, the most recent one of the highest quality was used. The GRADE evidence profiles have been prepared with footnotes that explain the judgements that were made.

In the majority of cases, the quality of evidence for various outcomes ranged from very low quality to moderate quality. The primary reason for this is a lack of availability of evidence for the setting for which the recommendations were made, i.e. patient population from LMICs. In all cases, the quality of evidence was downgraded due to indirectness.

The draft recommendations have been sent for external peer review, which are analysed by WHO. The peer reviewers were asked to comment primarily on the comprehensiveness and accuracy of the interpretation of the evidence base supporting the recommendations in the guideline. The document received positive appraisal; however, the comments of peer reviewers are then sent to the guideline expert panel members for their consideration and discussion. Based on the comments received, the WHO writing team will produce the final product. Comments and suggestions from peer reviewers will be addressed to the responsible officer for reply. Responses will be documented and made available upon request. The summary of peer reviewer comments from four independent experts with no conflict of interest is presented below; the full text is available upon request.

All peer reviewers were asked to submit a signed WHO Declaration of Interests form. Where interest was declared, legal advice was sought on whether the expert would be eligible for reviewing the document. The guideline development group is grateful to these reviewers for their contribution to the guideline.

Major comments of peer reviewers:

  • The guideline is focused mainly on treatment and does not address the issue of non-drug prevention such as tobacco or overweight control. Advice regarding these risk factors would be beneficial. (Response: provided in the treatment flowcharts.)
  • Advice on patient education and establishing a partnership “physician–patient” is important to mention. (Response: provided in the treatment flowcharts.)
  • Inhaled corticosteroids should include any other inhaled corticosteroids and not only beclometasone. (Response: see summary decision-making tables.)
  • Regarding stable COPD recommendations 1 and 4: the lack of studies for short-acting beta agonists >8 weeks appears to be the issue regarding the inability to recommend them regularly. It should be stated that there are no trials – it is not that the trials exist and demonstrate that there is no effect. The search is only up to 2002; in view of the importance of this and the probability of long-term benefits as described for trials >8 weeks, the guideline should make a clear interpretative comment about likely long-term benefits for symptoms and lung function. (Response: see summary decision-making tables.)

It is planned initially to introduce the guideline (English printed version as well as an electronic version on the WHO web site) at regional and subregional workshops that will be organized with country support in close consultation with regional WHO representatives. Implementing partners will be invited to these workshops for wider incorporation. The indicators used to evaluate the impact of interventions will be discussed and selected at the workshops. WHO headquarters will provide technical support at the country level for local adaptation of the guideline. Staff from headquarters and regional and country offices will be familiarized with the guideline in order to assist the countries. It is expected that this guideline will be reviewed in 2016.

Copyright © 2012, World Health Organization.

All rights reserved. Publications of the World Health Organization are available on the WHO web site (www.who.int) or can be purchased from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e-mail: tni.ohw@sredrokoob).

Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press through the WHO web site (http://www.who.int/about/licensing/copyright_form/en/index.html).

Bookshelf ID: NBK148629

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