NPA-GP: Guideline Methods (2023)
Nutrition and Physical Activity: General Population Systematic Review and
Evidence-Based Nutrition Practice Guideline Methods
The methodology for this project was developed using the process of the Academy of Nutrition and Dietetics, in accordance with the Standards for Developing Clinical Practice Guidelines from the National Academy of Science using grading and guideline development tools from the GRADE (Grading of Recommendations Assessment, Development and Evaluation) group.
Overview of the Development Process
Evidence-based recommendations are the product of a rigorous and systematic, step-by-step process. These steps are listed briefly, and described in detail in the sections below.
- Conduct a scoping review to determine literature availability;
- Recruit and select an expert panel;
- Determine priorities, gaps in research, and, consequently, Population-Intervention-Comparison-Outcome (PICO)-formatted systematic review research questions to support recommendations;
- Develop a priori eligibility criteria for the systematic review;
- Design a search plan and register on the PROSPERO database;
- An information specialist conducts the search of databases;
- Titles and abstracts from database searches are screened and hand searched for relevant articles; review full-text articles for inclusion;
- Trained evidence analysts extract data using a standardized tool and assess quality (risk of bias) for each included article;
- Study characteristics and results are summarized in tabular form and evidence for each outcome is synthesized qualitatively (evidence summary and conclusion statement), quantitatively (in meta-analyses when possible) and in tabular form (study characteristics, intervention characteristics, and summary of findings tables) for each outcome reported in included studies. Conclusion statements are graded according to Academy and GRADE principles.
- Expert panel members complete GRADE’s evidence-to-decision (EtD) framework to determine the best recommendations based on evidence, clinical expertise and client values.
- Recommendations are rated according to Academy principles and voted on and approved by expert panel members;
- The evidence-based nutrition practice guideline was reviewed externally by nine individuals with content expertise using the AGREE II tool. Ten practitioners tested using the EBNPG in practice and provided feedback in a focus group format.
- Authors responded to reviewer comments and updated the guideline accordingly.
- EBNPG is approved by the Council on Research at the Academy.
Supporting Systematic Review
A systematic review preceded and informed this EBNPG. The systematic review used methods from the Cochrane Collaboration’s Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) and from the Academy, adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and included meta-analyses. The risk of bias was assessed using the revised tool for randomized controlled trials (RCTs) (RoB2) and certainty of evidence was determined using the GRADE method and summary of findings table. The research question examined was:
In adults with or without cardiometabolic risk factors but no diagnosed disease, what is the effect of nutrition and physical activity interventions provided by nutrition and exercise practitioners, compared to no intervention, on physical activity amount, fruit and vegetable intake, waist circumference, percent weight loss for adults with overweight or obesity, fasting blood glucose, hemoglobin A1c (HbA1c) for adults with diabetes risk, quality of life, anxiety and depression and adverse events?
Randomized controlled trials were eligible for inclusion if they answered the research question, including the requirement that interventions were delivered by a dietitian, exercise practitioner, and/or a health coach. Unlike dietitians who have relatively standardized training across the globe, several certifications exist for exercise practitioners, which cannot be classified in the same way as nutrition practitioners. Exercise practitioners were included according to certifications recognized by the U.S. Registry of Exercise Professionals, including personal trainers, exercise physiologists and strength and conditioning coaches. Health coaches were identified according to the authors’ definition. The included studies were published from January 2010 to April 2, 2021, in the English language. Databases searched included Medline, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Sport Discus. The full search strategy can be found on the Evidence Analysis Library website. Briefly, the search required that study abstracts include a combination of diet terms (e.g., “eating,” “diet,” and “dietary intake,” etc.), exercise terms (e.g., “exercise,” “physical activity,” “aerobic activity,” and “muscle strength,” etc.), and counseling, behavior or therapy terms. A total of 11,205 unique titles/abstracts were screened, 472 full-text articles were assessed for inclusion, and 31 RCTs represented in 49 articles were included in the supporting systematic review. Practitioners providing nutrition and physical activity interventions were dietitians in 12 RCTs, dietitians and qualified exercise practitioners in ten RCTs and health coaches in six RCTs. Three RCTs utilized other combinations of practitioners.
Strengths and Limitations of Evidence
The body of included evidence demonstrated a consistent positive effect of interventions delivered by nutrition and exercise practitioners across a broad range of interventions. Heterogeneity in study interventions precluded making conclusions about the efficacy of specific intervention components, such as those delivered using telehealth or group interventions. Further, most studies were rated as having at least some concerns of risk of bias, primarily from lack of information regarding the randomization process and deviations from intended interventions. Some outcomes, such as quality of life, were reported in a few articles and had low certainty of evidence. Finally, the studies included did not allow for sub-analyses of specific sub-populations that may have higher risk of cardiometabolic diseases, such as adults with low socioeconomic status and those identifying as members of racial, ethnic or gender minority groups.
Guideline Development Process
Guideline recommendations were created following methods from the Academy and the Cochrane Collaboration’s GRADE methods. The team conducted the systematic review and translated evidence to practice recommendations using an Evidence-to-Decision (EtD) framework. Each recommendation was drafted from an EtD framework by six expert panel members of various disciplines, previously described. The EtD framework guided expert panel members in interpreting and translating evidence to action statements while considering the balance of benefits and harms, evidence certainty, and importance of affected outcomes, resource use, equity, client values, acceptability and feasibility to stakeholders, and clinical expertise. After the frameworks were completed independently by panel members, information was synthesized by the methodologist and thoroughly reviewed and edited by all team members. Final recommendation statements were unanimously approved by expert panel member voting. From the formulation of the systematic review research question through drafting the guideline, expert panel members were asked to consider application to and implementation of recommendations to practice. Each recommendation includes supporting evidence as well as implementation considerations for nutrition and exercise practitioners.
Grading of Recommendation Statements
Recommendation ratings include a number (1-2) and a letter (A-D). The number indicates the strength of the recommendation based on the certainty of evidence as well as clinical expertise and consideration of client values. Recommendations rated as “1” are strong and are generally applicable to the target population. Recommendations rated as “2” may have lower certainty and are considered weaker recommendations. Regardless of the rating, recommendations should only be applied after consideration of individual client circumstances. The letter represents the certainty or strength of the evidence supporting the recommendation from the systematic review, with evidence ranging from high (A) to very low (D). When multiple outcomes with different evidence ratings were considered for a recommendation statement, the team used definitions of evidence grades to guide grading of the recommendation statement.
Stakeholder Involvement and External Review
A guideline team including six registered dietitians or international equivalents, three exercise practitioners, and two health coaches all with practice or research experience with the populations of interest, and a systematic review and guideline methodologist conducted this EBNPG and the supporting systematic review. Expert panel members were selected by the Academy Council on Research’s Expert Panel Selection Subcommittee. The full team, including the systematic review/guideline methodologist and lead analyst, participated in formulating research questions, and conducting the systematic review. The expert panel drafted the recommendations and supporting information, including implementation considerations, and were encouraged to represent their clients’ needs and values throughout systematic review and guideline development. Expert panel members voted on and unanimously approved recommendation statements and ratings.
This EBNPG underwent peer review. Specifically, nine external peer reviewers working in the field of nutrition and physical activity interventions for the general population thoroughly reviewed the recommendations and supporting information, including implementation considerations. External peer reviewers utilized the Appraisal of Guidelines for Research Evaluation II (AGREE II) tool to determine the rigor of guideline development and were encouraged to provide feedback on the content of the recommendations and supporting information. In addition to peer review from content experts, the authors of the EBNPG aimed to gather direct feedback from ten nutrition and exercise practitioners working in the field in terms of feasibility and acceptability of the guideline, barriers and facilitators for implementation, and suggestions for improving incorporation into practice. Practitioners were recruited through several listservs, including the Nutrition Research Network and Dietetic Practice Group newsletters, at the Academy. Practitioners are encouraged to utilize the guideline in practice with a range of clients, including those who are healthy and those with cardiometabolic risk factors, as well as clients with a variety of experiences and backgrounds. Then, practitioners came together to describe client and practitioner feedback in a focus group conducted by the project manager. Feedback from peer reviewers and consumers were carefully reviewed by the guideline development team and suggested edits were incorporated when possible. The Council on Research reviewed responses to reviewer comments and the final guideline to ensure these perspectives were incorporated. The Council on Research voted to approve this guideline on March 1, 2023.
Monitoring, Evaluating and Auditing Guideline Implementation
The evidence-based cycle extends beyond creating evidence-based practice recommendations. Ideally, nutrition and exercise practitioners implement recommendations into practice, evaluate for efficacy, and re-evaluate and update accordingly. Physical activity research may be supported by collaborative efforts such as the U.S. Centers for Disease Control and Prevention’s (CDC) Physical Activity Policy Research and Evaluation Network (PAPREN). When determining which recommendation to prioritize for implementation, nutrition and exercise practitioners are encouraged to prioritize recommendations that will have the greatest impact on their specific circumstances and clients. Development of monitoring or auditing criteria to assess this EBNPG are beyond the scope of this EBNPG.
Academy guidelines are considered for update every five years. At that point, a scoping review is conducted to determine whether substantial literature on the topic has been published since the prior systematic review. The Academy’s Council on Research, informed by the research team, determines whether this EBNPG requires modification to no, some, or all recommendation statements.
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