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Cystic Fibrosis

CF: Guideline Overview (2020)

Guideline Overview 

Guideline Title 

Cystic Fibrosis Evidence-Based Nutrition Practice Guideline (2020)

Guideline Narrative Overview 

Introduction

Nutrition management is an established and essential component of overall care for all individuals with cystic fibrosis (CF) in order to prevent and remediate malnutrition. Nutrition status is strongly associated with pulmonary function and survival. Rapid advances in the understanding and treatment of CF, including the introduction of CFTR modulation therapies, necessitate evolution in medical nutrition therapy (MNT) for the many different manifestations of this complex disease.

Recently, two general nutrition care guidelines for CF were developed by the Thoracic Society of New Zealand and Australia and the European Society for Clinical Nutrition and Metabolism, the European Society for Paediatric Gastroenterology Hepatology and Nutrition and the European Cystic Fibrosis Society (ESPEN-ESPGHAN -ECFS) (Saxby et al 2017, Turck et al 2016). In the United States, The Cystic Fibrosis Foundation (CFF) has sponsored numerous recommendations and guidelines that include nutrition-related topics (Borowitz et al 2002, Aris et al 2005, Stallings et al 2008, Borowitz et al 2009, Tangpricha et al 2012, Schwarzenberg et al 2016).

The Academy of Nutrition and Dietetics Evidence Analysis Center (EAC) conducted a systematic review of the literature to develop an evidence-based practice guideline for primary nutrition issues in CF.  These guidelines are designed to complement, build upon, and expand the existing Australian/New Zealand, European, and CFF recommendations and guidelines. The EAC CF guidelines are intended to inform the practice of registered dietitian nutritionists (RDNs) who provide individualized nutrition care for children and adults with CF. The EAC CF guideline also identifies existing research gaps in the primary literature that require attention to improve nutrition practice.

In 1988, the seminal work of Corey et al, elucidated the impact of achieving and maintaining better weight and height on lifespan for individuals with CF (Corey et al 1988). The emphasis of nutrition therapy for CF shifted from a low-fat, high-protein diet prescribed to control symptoms of steatorrhea and abdominal discomfort to a high-energy, high-fat diet designed to promote weight gain. Twenty years after Corey, Stallings et al used US CF Foundation registry data to demonstrate a positive association between body mass index (BMI) and forced expiratory volume at one second (FEV1) percent predicted for children and adults with CF, reinforcing the importance of weight gain. (Stallings et al 2008) Nutritional management continued to focus on the attainment of BMI through the prescribed high-energy, high-fat, “CF legacy diet”. Diet quality and nutrient density received much less attention.

Recent studies of the diet records of children with CF in Australia and the European Union demonstrated the achievement of CF estimated energy requirements through overconsumption of energy-dense, nutrient-poor foods, particularly sugars, saturated fats, and highly processed foods.(Sutherland et al 2018, Calvo-Lerma et al 2019) This trend was especially pronounced in socioeconomically disadvantaged and rural settings (Sutherland et al 2018). In a US study of adults with CF, diets higher in added sugars, along with higher fasting glucose levels, were linked with increased visceral adipose tissue distribution in adults with CF (Bellissimo et al 2019). 

The landscape of nutrition care is changing for those with CF, particularly due to the introduction of CFTR modulation therapy, which may result in less severe symptoms, longer lifespan and less risk of undernutrition. The future health of adults and children with CF may be jeopardized by the continued reliance on a high-energy, nutrient-poor diet.  Although a paucity of data suggests individuals with CF benefit from general population-based nutrition recommendations, there is currently no data to demonstrate adults and children with CF are exempt from these recommendations.  The EAC guidelines for CF rely on the evidence-based, general nutrition recommendations derived from the systematic review supporting this guideline. Where evidence was not available to support recommendations specific to the CF population, sources such as the Centers for Disease Control, Academy of Nutrition and Dietetics, American Medical Association, American Heart Association, and American Academy of Pediatrics were utilized to serve as bases for modifications in dietary management of children and adults with CF. For nutrition topics outside the scope of the current guideline, the workgroup has identified, reviewed and approved of recommendations from external guidelines to guide practitioners on these topics (please see Recommendations Overview Table).

Guideline Development

This guideline is intended for use by the registered dietitian nutritionist (RDN) or international equivalent working with individuals with cystic fibrosis (CF). This guideline is intended to address gaps in current evidence-based practice guidelines and to address key questions that have arisen in CF nutrition practice due to developments in CF treatment, particularly CFTR modulation therapy. This guideline is based on systematic reviews conducted by the project team, consisting of RDNs who are practitioners and/or researchers, patient advocates and systematic review and guideline methodologists and evidence analysts. Recommendations were written based on an evidence-to-decision framework that incorporates evidence as well as clinical experience and the values of the individual with CF. When there was no evidence available for specific research questions, recommendations were based on expert experience and other supporting evidence. For nutrition topics outside of the scope of this guideline, external evidence-based guidelines were reviewed using the AGREE II tool and indidivual graded recommendations were voted on by workgroup members in order to provide practitioners with a comprehensive guide to CF nutrition care (see Overview  of Nutrition Topics in Cystic Fibrosis).

To view specific methods for the development of this guideline, please see the respective section.

Topics addressed in this Evidence-based Nutrition Practice Guideline include:

  • Medical Nutrition Therapy 
    • Frequency of MNT and RDN FTEs
    • MNT Approach
    • Nutrition Screening and Assessment
  • Dietary Intake
    • General Guidance
    • Dietary intake with CFRD or overweight/obesity
    • Macronutrient Distribution
    • Fiber Intake
    • Infant Feeding

The number of supporting documents for these topics is:

  • Recommendations:  28
  • Conclusion Statements: 69 
  • Evidence Summaries: 41
  • Article Worksheets: 35

Contributors

Please expand the “Project Team and Disclosures” to see the list of individuals including the expert workgroup members, methodologists and analysts for this project.

Revision

Academy guidelines are revisited every five years. A scoping review will be conducted to examine the need for new and revised recommendations based on the available science. The process includes:

  • Literature searches and evidence scoping to identify new research published since the previous searches were completed. Updated inclusion/exclusion criteria and search terms may be warranted.
  • Council on Research review to determine if the update will inlcude modification to all, some or no recommendations compared to the earlier version(s) of the guideline, or development of new recommendations.
  • Creation of a table comparing the new guideline and the older version of the guideline. The document will indicate which recommendations remained unchanged; updated, new; or not reviewed.

Using the Acadmey's EAL proces, an unbiased and transparent systematic review will be completed and the updated guideline published on the EAL. To learn more about the Academy's development process, download "Academy of Nutrition and Dietetics Methodology for Developing Evidence-Based Nutrition Practice Guidelines. J Acad Nutr Diet 2017 May 117; (5):794-804.

References:

  • Aris RM, Merkel PA, Bachrach LK, et al. Guide to bone health and disease in cystic fibrosis. The Journal of clinical endocrinology and metabolism. 2005;90(3):1888-1896.
  • Bellissimo MP, Zhang I, Ivie EA, et al. Visceral adipose tissue is associated with poor diet quality and higher fasting glucose in adults with cystic fibrosis. J Cyst Fibros. 2019;18(3):430-435.
  • Borowitz D, Baker RD, Stallings V. Consensus report on nutrition for pediatric patients with cystic fibrosis. J Pediatr Gastroenterol Nutr. 2002; 35(3):246-59.
  • Borowitz D, Robinson KA, Rosenfeld M, et al. Cystic Fibrosis Foundation evidence-based guidelines for management of infants with cystic fibrosis. J Pediatr. 2009;155(6):S73-93.
  • Calvo-Lerma J, Hulst J, Boon M, et al. The Relative Contribution of Food Groups to Macronutrient Intake in Children with Cystic Fibrosis: A European Multicenter Assessment. J Acad Nutr Diet. 2019;119(8):1305-1319.
  • Corey M, McLaughlin FJ, Williams M, Levison H. A comparison of survival, growth, and pulmonary function in patients with cystic fibrosis in Boston and Toronto. J Clin Epidemiol. 1988;41(6):583-591.
  • Saxby et al PC, Kench A, King S, Crowder T, van der Haak N and the Australian and New Zealand Cystic Fibrosis Nutrition Guideline Authorship Group. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. In. Sydney: Thoracic Society of Australia and New Zealand; 2017.
  • Schwarzenberg SJ, Hempstead SE, McDonald CM, et al. Enteral tube feeding for individuals with cystic fibrosis: Cystic Fibrosis Foundation evidence-informed guidelines. J Cyst Fibros. 2016;15(6):724-735.
  • Stallings V, Stark L, Robinson K, Feranchak A, Quinton H. Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: results of a systematic review. J Am Diet Assoc. 2008;108(5):832-839.
  • Sutherland R, Katz T, Liu V, et al. Dietary intake of energy-dense, nutrient-poor and nutrient-dense food sources in children with cystic fibrosis. J Cyst Fibros. 2018;17(6):804-810.
  • Turck D, Braegger CP, Colombo C, et al. ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with cystic fibrosis. Clin Nutr. 2016;35(3):557-577.
  • Tangpricha V, Kelly A, Stephenson A, et al. An update on the screening, diagnosis, management, and treatment of vitamin D deficiency in individuals with cystic fibrosis: evidence-based recommendations from the Cystic Fibrosis Foundation. Journal Clinical Endocrinol Metabol. 2012;97(4):1082-1093.
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