Objectives
Conduct a systematic review (SR) to determine the relationship between dietary macronutrient distribution and nutrition-related outcomes in pediatric and adult participants with cystic fibrosis (CF).
Methods
A literature search of Medline, CINAHL and Embase databases was conducted to identify peer-reviewed articles published from January 2002- May 2018 that examined human participants with CF and addressed the research objective. Articles were screened for relevance, data was extracted and summarized, and risk of bias was assessed by a multidisciplinary team of researchers, practitioners, patient advocates and SR methodologists.
Results
A total of 2409 articles were identified in the search and eight cross-sectional studies and one case-control study met inclusion criteria (N = 4 in pediatrics, N = 4 in adults, N = 1 combined). Evidence quality was low due to weak study designs, small samples size and inconsistent outcome reporting. Available studies did not show statistically significant relationships between dietary macronutrient distribution and lung function (FEV1%) (3 studies) when estimated protein intake ranged from 10–23% of energy, fat intake from 20–46% of energy and carbohydrate intake from 32–67% of energy. Macronutrient distribution was not significantly associated with anthropometric measurements/growth (3 studies), gastrointestinal symptoms (2 studies), glucose fluctuations (1 study) or lipid profile (1 study) in this SR. There were no studies identified examining the relationship between macronutrient distribution and mortality or Quality of Life. Meta-analysis was not possible due to the low quality of data reported.
Conclusions
Recent evidence describing the relationship between dietary macronutrient distribution and nutrition-related outcomes in participants with CF is sparse and low in quality. The evidence reviewed does not suggest that dietary macronutrient distribution is related to key clinical CF outcomes. Higher-quality trials and longitudinal studies are needed to confirm these findings. The need for updated dietary studies is particularly important in light of recent therapeutic advances that are changing the clinical course of individuals with CF.
Funding Sources
Academy of Nutrition and Dietetics and the Medical Nutrition Practice Group DPG.
Objectives
Individuals with cystic fibrosis (CF) are at high risk for malnutrition and poor growth. New drugs that modulate CF transmembrane receptor (CFTR) function are available, although their effects on anthropometric parameters are not clear. This systematic review aimed to determine if various CFTR modulator therapies affect weight and growth parameters in individuals with CF.
Methods
A literature search was conducted using MEDLINE, CINAHL and Embase databases for peer-reviewed, randomized controlled trials (RCT) published from January 2002 to May 2018 that examined the effect of CFTR modulation therapy on weight and growth parameters in children and adults with CF. Articles were screened for relevance, data was extracted and summarized, and risk of bias was assessed to determine the quality of evidence.
Results
A total of 612 original articles were identified, and 13 articles representing 10 RCTs were included in qualitative synthesis and three were included in quantitative synthesis. All but one RCT demonstrated low risk of bias. The targeted class of CFTR mutation varied by RCT. Studies indicated that, in children and adults with CF with class III mutations, ivacaftor treatment alone increased weight and BMI (4 RCTs), but it did not influence growth in individuals with class II (1 RCT) or class IV mutations (1 RCT). Treatment with ivacaftor + lumacaftor in adults homozygous for the F508del CFTR mutation (class II) increased BMI following 24 weeks of treatment (2 RCTs), but there was no effect in adults heterozygous for the mutation treated for 8 weeks (1 RCT). Treatment with lumacaftor + tezacaftor in individuals ages 12–20 years with class II mutations did not change growth parameters (1 RCT).
Conclusions
Effects of CFTR modulators on increasing weight and growth in individuals with CF are likely dependent on the therapy formulation (single vs combination therapy) and the targeted CFTR mutation. Whereas ivacaftor alone increases weight and growth parameters in individuals with class III mutations, ivacaftor + lumacaftor is more effective at increasing BMI in adults homozygous for the class II F508del CFTR mutation. Additional studies are needed to determine effects of other CFTR modulator drugs on growth parameters in individuals with varying CFTR mutations.
Funding Sources
Academy of Nutrition and Dietetics/Medical Nutrition DPG, National Institutes of Health.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.