Nutrition

4. Retrieve, summarize and present the evidence

Identifying, appraising and synthesizing relevant evidence

A systematic and comprehensive retrieval of systematic reviews and primary literature will be conducted for published and unpublished studies with no language restriction. If the priority questions cannot be answered with the currently available systematic reviews, a new systematic review will be commissioned. If a systematic review is older than two years, a search of primary literature will be conducted to identify any new studies. If a new systematic review is needed, or if a systematic review needs updating, a protocol will be drafted and sent for comments to the Guideline Group prior to initiating the work.

The search strategy for identifying the published, unpublished and ongoing studies and systematic reviews will be documented carefully. Additionally, a systematic evaluation of existing recent national and international guidelines will be reviewed, if available.

Grading the quality of the evidence

The evidence profiles using the Grading of Recommendations Assessment, Development and Evaluation (GRADE; http://www.gradeworkinggroup.org/) methodology for each outcome will be available for the discussions. If this is not part of the systematic review it will be commissioned separately. For each question, data on the priority benefits and harms will be summarized.

A summary of the evidence GRADE tables will be sent to registered members of the Key External Experts and Stakeholders Panel prior to the Technical Consultation with the Guideline Group so that any missing relevant evidence can be identified. These tables, as well as the systematic reviews on which the recommendations are made, will be available to the end users on our website.

Grading the strength of the recommendation

The determinants of the strength of the recommendations will be based on the quality of the evidence, balance between desirable and undesirable effects, values and preferences and costs (resource allocation). Using the GRADE system, a strong recommendation for or against an intervention will be made when the Guideline Group is confident that the desirable effects of adherence to the recommendation would outweigh any undesirable effects.

A weak recommendation will be made when the panel concludes that the desirable effects of adherence to the recommendation probably outweigh the undesirable effects, but confidence about these trade-offs is lacking. This may be due to the absence of high quality evidence, the presence of imprecise estimates of benefits or harms, small benefits, or when the benefits may not be worth the costs.

The GRADE evidence tables will provide detailed footnotes explaining all judgments that were made and the basis for those judgments which may reduce or increase the strength of recommendations, especially when there is weak evidence.

Consideration of values and preferences

Key values and preferences that may have influenced decisions in making recommendations will be identified. Judgments will be explicitly stated and input from those affected (i.e. public health community, citizens, policy makers) will be sought when possible.

Consideration of resource use (costs) associated with the health interventions

Information on the economic implications of each recommendation and its alternatives will be included where relevant, with the aim of assisting end-users in the evaluation of the potential consequences of different practices. Where relevant, this will include a basic description of resources and costs for each intervention considered and its alternative(s) and/or a review of existing economic studies for each recommendation.


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