Body composition and lung function in cystic fibrosis and their association with adiposity and normal-weight obesity

Nutritional status in the era of highly effective CFTR modulators

Advances in cystic fibrosis (CF) diagnostics and therapeutics have led to improved health and longevity, including increased body weight and decreased malnutrition in people with CF. Highly effective CFTR modulator therapies (HEMT) are associated with increased weight through a variety of mechanisms, accelerating trends of overweight and obesity in the CF population. Higher body mass index (BMI) is associated with improved pulmonary function in CF, yet the incremental improvement at overweight and obese BMIs is not clear. Improvements in pulmonary health with increasing BMI are largely driven by increases in fat-free mass (FFM), and impact of HEMT on FFM is uncertain. While trends toward higher weight and BMI are generally seen as favorable in CF, the increased prevalence of overweight and obesity has raised concern for potential risk of traditional age- and obesity-related comorbidities. Such comorbidities, including impaired glucose tolerance, hypertension, cardiac disease, hyperlipidemia, fatty liver, colon cancer, and obstructive sleep apnea, may occur on top of pre-existing CF-related comorbidities. CF nutrition recommendations are evolving in the post-modulator era to more individualized approaches, in contrast to prior blanket high-fat, high-calorie prescriptions for all. Ultimately, it will be essential to redefine goals for optimal weight and nutritional status to allow for holistic health and aging in people with CF.

Impaired intestinal free fatty acid transport followed by chylomicron malformation, not pancreatic insufficiency, cause metabolic defects in cystic fibrosis

Intestinal disease is one of the earliest manifestations of cystic fibrosis (CF) in children and is closely tied to deficits in growth and nutrition, both of which are directly linked to future mortality. Patients are treated aggressively with pancreatic enzyme replacement therapy and a high-fat diet to circumvent fat malabsorption, but this does not reverse growth and nutritional defects. We hypothesized that defects in chylomicron production could explain why CF body weights and nutrition are so resistant to clinical treatments. We used gold standard intestinal lipid absorption and metabolism approaches, including mouse mesenteric lymph cannulation, in vivo chylomicron secretion kinetics, transmission electron microscopy, small intestinal organoids, and chylomicron metabolism assays to test this hypothesis. In mice expressing the G542X mutation in cystic fibrosis transmembrane conductance regulator (CFTR-/- mice), we find that defective FFA trafficking across the epithelium into enterocytes drives a chylomicron formation defect. Furthermore, G542X mice secrete small, triglyceride-poor chylomicrons into the lymph and blood. These defective chylomicrons are cleared into extraintestinal tissues at ∼10-fold faster than WT chylomicrons. This defect in FFA absorption resulting in dysfunctional chylomicrons cannot be explained by steatorrhea or pancreatic insufficiency and is maintained in primary small intestinal organoids treated with micellar lipids. These studies suggest that the ultrahigh-fat diet that most people with CF are counselled to follow may instead make steatorrhea and malabsorption defects worse by overloading the absorptive capacity of the CF small intestine.

Predicting weight gain in patients with cystic fibrosis on triple combination modulator

BACKGROUND

Cystic fibrosis (CF) is caused by CF transmembrane conductance regulator (CFTR) gene mutations producing dysfunctional CFTR proteins leading to progressive clinical disease. Elexacaftor-tezacaftor-ivacaftor (ETI) remarkably improves lung disease but is associated with substantial weight gain.

STUDY DESIGN AND METHODS

We performed a single-center longitudinal study predicting 6-month weight gain after ETI initiation. We used linear mixed effects modeling (LME) to determine association of ETI treatment with changing body mass index (BMI). Using linear regression, we examined BMI prediction models with distinct combinations of main effects to identify a model useful for patient counseling. We used up to eight commonly observed clinical characteristics as input variables (age, sex, percent predicted FEV1 [FEV1%], F508del homozygous state, pancreatic sufficiency, HgbA1c, prior modulator use and prior year number of pulmonary exacerbations).

RESULTS

We evaluated 154 patients (19-73 years old, 54% female, FEV1% = 19-121, 0-6 prior year pulmonary exacerbations). LME demonstrated an association between ETI use and weight increases. Exhaustive testing suggested a parsimonious linear regression model well-fitted to data that is potentially useful for counseling. The two variable model shows that on average, BMI decreases by 0.045 (95% Confidence Interval [CI] = -0.069 to -0.021, p < 0.001) for every year of age and increases by 0.322 (CI = 0.142 to 0.502, p = 0.001) for each additional prior year exacerbation at the time of ETI initiation.

INTERPRETATION

Young patients with many prior year pulmonary exacerbations likely have the largest 6 month weight gain after starting ETI.

Pulmonary function and body composition parameters of children with cystic fibrosis from a hight complexity institution between 2015 and 2018

BACKGROUND

An adequate nutritional status in patients with cystic fibrosis correlates with higher survival and better pulmonary function. Body mass index (BMI) is an anthropometric indicator with independent association with pulmonary function, and it can hide alterations of nutritional status in cystic fibrosis.

OBJECTIVE

To determine the relationship of lung function with BMI and body composition parameters in children with cystic fibrosis in a Hight Complexity institution between 2015 and 2018.

MATERIALS AND METHODS

It was an observational study with analytical, cross-sectional, and retrospective scope, including 33 patients between 5 and 17 years old. Spearman's test was applied to evaluate correlation of FEV1 (forced expiratory volume in first second) with BMI and five body composition parameters by bioelectrical impedance using InbodyS10 equipment. Statistical significance was considered with p < 0.05.

RESULTS

Positive correlation was obtained between FEV1 and appendicular skeletal muscle mass between lung function and percentage of fat-free mass (p = 0.006) and phase angle (p = 0.001). Percent fat mass had a negative correlation with FEV1 (p = 0.007). BMI and fat free mass index did not correlate with lung function (p = 0.085).

CONCLUSIONS

Appendicular skeletal muscle mass correlated better than BMI with lung function in children with cystic fibrosis. It is recommended to perform anthropometric follow-up by BMI complemented with body composition study in children with cystic fibrosis. Analyses with larger populations are required to standardize its use.

ESPEN-ESPGHAN-ECFS guideline on nutrition care for cystic fibrosis

BACKGROUND

Nutritional status is paramount in Cystic Fibrosis (CF) and is directly correlated with morbidity and mortality. The first ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with CF were published in 2016. An update to these guidelines is presented.

METHODS

The study was developed by an international multidisciplinary working group in accordance with officially accepted standards. Literature since 2016 was reviewed, PICO questions were discussed and the GRADE system was utilized. Statements were discussed and submitted for on-line voting by the Working Group and by all ESPEN members.

RESULTS

The Working Group updated the nutritional guidelines including assessment and management at all ages. Supplementation of vitamins and pancreatic enzymes remains largely the same. There are expanded chapters on pregnancy, CF-related liver disease, and CF-related diabetes, bone disease, nutritional and mineral supplements, and probiotics. There are new chapters on nutrition with highly effective modulator therapies and nutrition after organ transplantation.

What do people with cystic fibrosis eat? Diet quality, macronutrient and micronutrient intakes (compared to recommended guidelines) in adults with cystic fibrosis-A systematic review

BACKGROUND

Treatment advancements have improved life expectancy and nutritional status of people with cystic fibrosis (CF). Alongside reductions in malnutrition, incidences of overweight, obesity and risk factors for diet-related chronic diseases have increased in recent years. This study aimed to synthesise the available literature on diet quality, macronutrient and micronutrient intakes compared to the recommended guidelines in adults with CF, an essential step in deducing the optimal dietary pattern and intakes for CF adults.

METHODS

A systematic search of five electronic databases from inception until April 2023 was conducted using keywords related to CF, diet quality and nutrient intakes.

RESULTS

Twenty-one studies were included comprising 18 cross-sectional, one cohort and two case control studies, reporting data from 724 adults with CF. Energy and / or macronutrient intake data was reported across 17 cohorts, eight studies provided micronutrients data, and diet quality was determined for four CF cohorts by using a diet quality score, and / or categorising food intake into servings per day for food groups and comparing findings to national dietary guidelines. Although energy intake recommendations were met, and most micronutrient requirements were achieved through supplementation, total energy intake from fat was above recommendations and diet quality was poor.

CONCLUSION

This is the first systematic review comprehensively evaluating literature on dietary intakes of adults with CF. Energy-dense, nutrient-poor foods contribute to intakes which pose risk in developing diet-related chronic diseases. Revision of dietary guidelines and practice change in CF nutritional therapy is warranted to optimise nutrition and health outcomes.

Weight a minute: Exploring the effect on weight and body composition after the initiation of elexacaftor/tezacaftor/ivacaftor in adults with CF

BACKGROUND

Life expectancy for people with CF (PwCF) continues to increase. However, a trend of overweight and obesity is emerging along with concern of developing comorbitities. Body composition (BC) is associated with several health indices. However, body mass index (BMI) does not provide information on BC.

METHODS

BMI, fat mass (FM), fat free mass (FFM), using bioelectrical impedance, lung function and sweat chloride (SwCl) were assessed in adult PwCF in routine clinic before and after commencement of the CFTR modulator Elexacaftor/Tezacaftor/Ivacaftor.

RESULTS

109 PwCF (76 male) underwent assessments at both time points. In all PwCF a significant upward trend in BMI was observed (p < 0.001). Males significantly gained more FFM compared to females (p0.03), whilst prevalence of normal weight obesity increased primarily in females (25-38%).

CONCLUSION

Routine BC assessment identifies individuals with elevated FM or depleted FFM enabling individualised care with the focus of optimising BC.

Body composition and body mass index measures from 8 to 18 years old in children with cystic fibrosis

BACKGROUND

Historically, body mass index (BMI) >50th percentile has represented optimal nutritional status in children with cystic fibrosis (CF) due to its positive association with lung function. Body composition parameters including fat-free mass index (FFMI) have been suggested as a more physiological nutrition benchmark.

AIMS

(1) describe changes in body composition with age and gender; (2) assess the correlation between measures of nutritional status (FFMI-z, FMI-z, BMI-z) and lung function (forced expiratory volume in one second predicted; FEV1pp).

METHODS

This retrospective, mixed cross-sectional and serial measures study consisted of children with CF (8 to 18 years) attending Sydney Children's Hospital (2007-2020). FFMI and fat mass index (FMI) were taken from biennial dual energy x-ray absorptiometry (DXA) scans. Z-scores were derived using Well's reference population [1]. Repeated measures correlation analyses assessed correlations between FFMI-z, FMI-z, and BMI-z with FEV1pp.

RESULTS

339 DXA reports were analysed from 137 patients. There were slight downwards trends in BMI-z and FMI-z, and an upwards trend in FFMI-z with increasing age and across both genders. Females had higher FMI-z and FFMI-z than males from 12.5 years. There was a weak, positive correlation between FEV1pp and BMI-z (r = 0.14, p = 0.04), and FFMI-z (r = 0.25, p<0.001). FMI-z had no correlation with FEV1pp (r=-0.06, p = 0.41).

CONCLUSION

Deficits in FFMI exist despite increasing trends with age. FFMI-z and BMI-z had a weak, positive correlation with FEV1pp. In contemporary cohorts, nutritional status (reflected by surrogate markers such as FFMI and BMI) may be less influential upon lung function than in previous decades. [1]: Wells, J.C., et al. Body-composition reference data for simple and reference techniques and a 4-component model: a new UK reference child. Am. J. Clin. Nutr.96, 1316-1326 (2012).

The impact of elexacaftor/tezacaftor/ivacaftor on body composition in a small cohort of youth with cystic fibrosis

BACKGROUND

The effects of elexacaftor-tezacaftor-ivacaftor (ETI) on body composition in people with CF (pwCF) are unknown.

METHODS

Dual-energy X-ray absorptiometry fat-free mass and fat mass adjusted for height (FMI) as well as oral glucose tolerance test derived measures of insulin secretion and sensitivity were compared before and after ETI initiation in eight pwCF.

RESULTS

Patients median age: 22 years interquartile range (IQR: 16-28), 87.5% male, median time on ETI:11 months. Weight z-score increased from -0.52 to 0.18 (p = 0.014); FMI increased from 4.12 to 6.29 (p = 0.014). Insulin secretion (C pep iAUC/Gluc iAUC) increased from 8.71 to 14.21 (p = 0.021), insulin resistance (HOMA2 IR) increased from 0.73 to 1.25 (p = 0.014) and insulin sensitivity decreased (Matsuda) 8.88 to 5.58 (p = 0.036).

CONCLUSIONS

ETI resulted in increased weight and fat mass. BMI and muscle mass did not change. Both insulin secretion and insulin resistance increased. Longer-term metabolic consequences of ETI need further investigation.

Body composition and functional correlates of CF youth experiencing pulmonary exacerbation and recovery

BACKGROUND

Youth with cystic fibrosis (CF) and pulmonary exacerbation (PEx) often experience weight loss, then rapid weight gain. Little is known about body composition and its relationship to functional outcomes during this critical period.

METHODS

Twenty CF youth experiencing PEx were assessed on the day following admission and 7-17 days later at discharge for body mass index (BMI), fat mass index (FMI), lean mass index (LMI), skeletal muscle mass index (SMMI), and functional measures: percent predicted forced expiratory volume in 1 second (FEV1) (ppFEV1), maximal inspiratory and expiratory pressures (MIPs and MEPs), and handgrip strength (HGS). Changes from admission to discharge and correlations among body composition indices and functional measures at both times are reported.

RESULTS

Upon admission, participant BMI percentile and ppFEV1 varied from 2 to 97 and 29 to 113, respectively. Thirteen had an LMI below the 25th percentile and nine had a percent body fat above the 75th percentile. BMI and FMI increased significantly (p = 0.03, 0.003) during hospitalization. LMI and SMMI did not change. FEV1 and MIPS increased (p = 0.0003, 0.007), independent of weight gain, during treatment. HGS did not improve.

CONCLUSIONS

Many youth with CF, independent of BMI, frequently carried a small muscle mass and disproportionate fat at the time of PEx. During hospital treatment, weight gain largely represented fat deposition; muscle mass and strength did not improve. A need for trials of interventions designed to augment muscle mass and function, and limit fat mass accretion, at the time of PEx is suggested by these observations.

Updates in Nutrition Management of Cystic Fibrosis in the Highly Effective Modulator Era

Attainment and maintenance of good nutrition has been an important aspect of management in cystic fibrosis (CF) for decades. In the era of highly effective modulator therapy for CF, the quality of the nutrients we recommend is increasingly important. Our therapy must support our patients' health for many years beyond what we previously thought. Preventing cardiovascular disease, reducing hyperlipidemia, and optimizing lean body mass for active, longer lives now join the long-standing goal of promoting lung function through nutrition. This chapter summarizes recent developments in nutrition in people with CF, with an eye to the evolution of our practice.

Nutritional status and lung function in children with pancreatic-sufficient cystic fibrosis

BACKGROUND

There is a strong association between nutrition and long-term FEV1 in cystic fibrosis (CF), but studies have been driven by data from subjects with pancreatic insufficiency (PI-CF). We thus evaluated the association between body mass index (BMI) and FEV1 percent-predicted (FEV1pp) in children with pancreatic sufficiency (PS-CF) and contrasted it with the association in PI-CF.

METHODS

We utilized data from the CF Foundation Patient Registry. The cohort included children born 1995-2010, diagnosed <2 years of age, and who had annualized data on BMI percentile and FEV1pp at ages 6-16 years. Pancreatic status was defined based on pancreatic enzyme replacement therapy. The association between BMI and FEV1 was evaluated using linear and mixed-effects longitudinal regression.

RESULTS

There were 424 children with PS-CF and 7,849 with PI-CF. The association between BMI and FEV1 differed significantly by pancreatic status: each 10-pct higher BMI was associated with 2% [95%CI = 1.9-2.1] higher FEV1pp in PI-CF, compared to just 0.9% [0.5-1.3] in PS-CF (PINTERACTION < 0.001). Within the at-risk nutritional category (BMI <25pct), each 10-pct higher BMI was associated with 5% higher FEV1pp in PI-CF, but no significant increase in PS-CF. Moreover, in PS-CF, overweight/obesity (BMI ≥85pct) was associated with decreasing FEV1pp. In addition, FEV1pp decline through age 20 years in youth with PS-CF was modest (-0.6% per year) and independent of BMI (BMI*age PINTERACTION = 0.37).

CONCLUSIONS

In children with PS-CF, BMI remains an important determinant of lung function. However, it may be less critical to attain a BMI >50th percentile; and BMI ≥85th percentile may be detrimental.

Cardiometabolic risk factors in adults with normal weight obesity: A systematic review and meta-analysis

Normal weight obesity (NWO) is a new emerging phenotype of obesity, defined as a normal body mass index with a high body fat percentage. While several studies have described the impact of NWO on cardiometabolic risk factors, the association between them remains uncertain. This meta-analysis systematically evaluated cardiometabolic risk factors in adults with NWO compared to adults with normal weight lean (NWL). A systematic literature search was performed from the inception until September 21, 2021 in order to comprehensively search for all observational studies that had three important variables, including adults (age ≥18 years old), NWO and cardiometabolic risk factors including metabolic syndrome, hypertension, diabetes mellitus, dyslipidaemia or all laboratory findings related to cardiometabolic risk factors. Twenty-four cross-sectional studies with a total of 75 201 subjects are included in the qualitative and quantitative analysis. Overall, older age and female sex are more likely in NWO population. Compared to NWL, NWO is significantly associated with cardiometabolic risk factors, including metabolic syndrome (OR = 2.24 [1.74, 2.89]; p < .001; I²  = 76%, P_{heterogeneity}  < 0.001), hypertension (OR = 1.60[1.36, 1.89]; p < .001; I²  = 76%, P_{heterogeneity}  < 0.001), diabetes mellitus (OR = 1.72[1.54, 1.92]; p < .001; I²  = 47%, P_{heterogeneity}  < 0.001), dyslipidaemia (OR = 1.50 [1.03, 2.18]; p = .03; I²  = 94%, P_{heterogeneity}  < 0.001) and other laboratory findings, except for C-reactive protein in both sexes group; and adiponectin levels in female group. Our meta-analysis showed that NWO was associated with cardiometabolic risk factors. Thus, the traditional definition of obesity using the BMI criteria should be challenged, as those with NWO might still be exposed to a heightened risk of cardiometabolic disorders. Nonetheless, further prospective cohort studies are needed better to understand this syndrome.

A Practical Approach to Identifying Pediatric Disease-Associated Undernutrition: A Position Statement from the ESPGHAN Special Interest Group on Clinical Malnutrition

ABSTRACT

Disease-associated undernutrition (DAU) is still common in hospitalized children and is generally accepted to be associated with adverse effects on disease outcomes; hence making proper identification and assessment essential in the management of the sick child. There are however several barriers to routine screening, assessment, and treatment of sick children with poor nutritional status or DAU, including limited resources, lack of nutritional awareness, and lack of agreed nutrition policies. We recommend all pediatric facilities to 1) implement procedures for identification of children with (risk of) DAU, including nutritional screening, criteria for further assessment to establish diagnosis of DAU, and follow-up, 2) assess weight and height in all children asa minimum, and 3) have the opportunity for children at risk to be assessed by a hospital dietitian. An updated descriptive definition of pediatric DAU is proposed as "Undernutrition is a condition resulting from imbalanced nutrition or abnormal utilization of nutrients which causes clinically meaningful adverse effects on tissue function and/or body size/composition with subsequent impact on health outcomes." To facilitate comparison of undernutrition data, it is advised that in addition to commonly used criteria for undernutrition such as z score < -2 for weight-for-age, weight-for-length, or body mass index <-2, an unintentional decline of >1inthese z scores over time should be considered as an indicator requiring further assessment to establish DAU diagnosis. Since the etiology of DAU is multifactorial, clinical evaluation and anthropometry should ideally be complemented by measurements of body composition, assessment of nutritional intake, requirements, and losses, and considering disease specific factors.

Brazilian Guidelines for Nutrition in Cystic Fibrosis

OBJECTIVE

To develop a scientific consensus on nutrition in cystic fibrosis.

METHODS

Sixteen coordinators elaborated relevant questions on nutritional therapy in cystic fibrosis, which were divided into six sections: nutritional assessment, nutritional recommendations, nutritional intervention, dietary counseling, special situations and enzyme replacement, and gastrointestinal manifestations. Two to three specialists in the field were responsible for each section and obtaining answers formulated based on standardized bibliographic searches. The available literature was searched in the PubMed®/MEDLINE database, after training and standardization of search strategies, to write the best level of evidence for the questions elaborated. Issues related to disagreement were discussed until a consensus was reached among specialists, based on the current scientific literature.

RESULTS

Forty-two questions were prepared and objectively answered, resulting in a consensus of nutritional therapy in cystic fibrosis.

CONCLUSION

This work enabled establishing a scientific consensus for nutritional treatment of cystic fibrosis patients.

The Changing Landscape of Nutrition in Cystic Fibrosis: The Emergence of Overweight and Obesity

Cystic fibrosis has historically been characterized by malnutrition, and nutrition strategies have placed emphasis on weight gain due to its association with better pulmonary outcomes. As treatment for this disease has significantly improved, longevity has increased and overweight and obesity have emerged issues in this population. The effect of excess weight and adiposity on CF clinical outcomes is unknown but may produce similar health consequences and obesity-related diseases as those observed in the general population. This review examines the prevalence of overweight and obesity in CF, the medical and psychological impact, as well as the existing evidence for treatment in the general population and how this may be applied to people with CF. Clinicians should partner with individuals with CF and their families to provide a personalized, interdisciplinary approach that includes dietary modification, physical activity, and behavioral intervention. Additional research is needed to identify the optimal strategies for preventing and addressing overweight and obesity in CF.

Effect of elexacaftor-tezacaftor-ivacaftor on body weight and metabolic parameters in adults with cystic fibrosis

BACKGROUND

Though weight gain has been reported in some clinical trials of CFTR modulators, the effect of elexacaftor-tezacaftor-ivacaftor on body weight, body mass index (BMI), blood pressure, lipids and glycemic control in the real-world setting remains incompletely described.

METHODS

We performed a single-center, retrospective, observational analysis of the effect of elexacaftor-tezacaftor-ivacaftor on body weight and cardiometabolic parameters in 134 adult CF patients of the Washington University Adult Cystic Fibrosis Center. Body weight, BMI, and blood pressure were extracted from outpatient clinic visits for the year preceding and the period following the initiation of elexacaftor-tezacaftor-ivacaftor. Other metabolic parameters were extracted at baseline and at latest available follow-up.

RESULTS

A mean of 12.2 months of follow-up data was available for analysis. The mean rate of change in BMI was 1.47 kg/m²/yr (95% CI, 1.08 to 1.87) greater after initiation of elexacaftor-tezacaftor-ivacaftor. Significant increases in blood pressure were observed. In those without CFRD, random blood glucose and hemoglobin A1c were decreased after elexacaftor-tezacaftor-ivacaftor initiation. In those with CFRD, elexacaftor-tezacaftor-ivacaftor increased serum total cholesterol, HDL-cholesterol, and LDL-cholesterol.

CONCLUSIONS

In this single-center, retrospective, observational study of 134 adults with CF, initiation of elexacaftor-tezacaftor-ivacaftor was associated with increases in BMI at a mean follow up of 12.2 months. Changes in other cardiometabolic risk factors were also observed. Widespread use of elexacaftor-tezacaftor-ivacaftor may be expected to increase the incidence of overnutrition in the CF population.

Association of Body Mass Index With Clinical Outcomes in Patients With Cystic Fibrosis: A Systematic Review and Meta-analysis

IMPORTANCE

The prevalence of overweight (body mass index [BMI] = 25-29.9 [calculated as weight in kilograms divided by height in meters squared]) and obesity (BMI ≥30) is increasing among patients with cystic fibrosis (CF). However, it is unclear whether there is a benefit associated with increasing weight compared with the reference range (ie, normal) in CF.

OBJECTIVE

To evaluate the association of altered BMI or body composition and clinical outcomes in patients with CF.

DATA SOURCES

For this systematic review and meta-analysis, the literature search was conducted November 2, 2020, of 3 databases: MEDLINE (via PubMed), Embase, and Cochrane Central Register of Controlled Trials.

STUDY SELECTION

Patients older than 2 years diagnosed with CF with altered body composition or BMI were compared with patients having the measured parameters within the reference ranges. Records were selected by title, abstract, and full text; disagreements were resolved by consensus. Cohort studies and conference abstracts were eligible; articles with no original data and case reports were excluded.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data, which were validated by a third author. Studies containing insufficient poolable numerical data were included in the qualitative analysis. A random-effects model was applied in all analyses.

MAIN OUTCOMES AND MEASURES

Pulmonary function, exocrine pancreatic insufficiency (PI), and CF-related diabetes (CFRD) were investigated as primary outcomes. Odds ratios (ORs) or weighted mean differences (WMDs) with 95% CIs were calculated. The hypothesis was formulated before data collection.

RESULTS

Of 10 524 records identified, 61 met the selection criteria and were included in the qualitative analysis. Of these, 17 studies were included in the quantitative synthesis. Altogether, 9114 patients were included in the systematic review and meta-analysis. Overweight (WMD, -8.36%; 95% CI, -12.74% to -3.97%) and obesity (WMD, -12.06%; 95% CI, -23.91% to -0.22%) were associated with higher forced expiratory volume in the first second of expiration compared with normal weight. The odds for CFRD and PI were more likely in patients of normal weight (OR, 1.49; 95% CI, 1.10 to 2.00) than in those who were overweight (OR, 4.40; 95% CI, 3.00 to 6.45). High heterogeneity was shown in the analysis of pulmonary function (I2 = 46.7%-85.9%).

CONCLUSIONS AND RELEVANCE

The findings of this systematic review and meta-analysis suggest that the currently recommended target BMI in patients with CF should be reconsidered. Studies with long-term follow-up are necessary to assess the possible adverse effects of higher BMI or higher fat mass in patients with CF.

The Relationship between Body Composition, Dietary Intake, Physical Activity, and Pulmonary Status in Adolescents and Adults with Cystic Fibrosis

Measures of body fat and lean mass may better predict important clinical outcomes in patients with cystic fibrosis (CF) than body mass index (BMI). Little is known about how diet quality and exercise may impact body composition in these patients. Dual X-ray absorptiometry (DXA) body composition, 24-h dietary recall, and physical activity were assessed in a cross-sectional analysis of 38 adolescents and adults with CF and 19 age-, race-, and gender-matched healthy volunteers. Compared with the healthy volunteers, participants with CF had a lower appendicular lean mass index (ALMI), despite no observed difference in BMI, and their diets consisted of higher glycemic index foods with a greater proportion of calories from fat and a lower proportion of calories from protein. In participants with CF, pulmonary function positively correlated with measures of lean mass, particularly ALMI, and negatively correlated with multiple measures of body fat after controlling for age, gender, and BMI. Higher physical activity levels were associated with greater ALMI and lower body fat. In conclusion, body composition measures, particularly ALMI, may better predict key clinical outcomes in individuals with CF than BMI. Future longitudinal studies analyzing the effect of dietary intake and exercise on body composition and CF-specific clinical outcomes are needed.

Trends in Growth and Maturation in Children with Cystic Fibrosis Throughout Nine Decades

Since cystic fibrosis (CF) was first described in 1938, there have been many discoveries and innovations in the field, each having a profound impact on survival, growth and quality of life. For example, the introduction of enteric-coated pancreatic enzyme microspheres increased fat absorption and improved nutritional status. Early detection of CF through newborn screening facilitated prompt nutritional intervention for infants at high risk of malnutrition. Use of anti-pseudomonal therapy, such as inhaled tobramycin, increased weight gain and pulmonary function in addition to reducing pulmonary exacerbations. Similarly, DNAse and hypertonic saline improved pulmonary function and reduced exacerbations. The identification of the CFTR gene and its protein product were fundamental in understanding the pathophysiology of CF and paved the way for advances in both diagnosis and management. In fact, CFTR modulator therapies have revolutionized the care for individuals with CF. Here, we examine the impact of these interventions on the nutritional status, growth and pubertal maturation of children and adolescents with CF.

Nutritional assessment and rehabilitation in children with bronchiectasis and childhood interstitial lung diseases: effects on pulmonary functions and clinical severity

Background

Nutrition is recognized as a modifiable contributor to bronchiectasis and interstitial lung diseases (ChILD) development and progression. Nutritional interventions have great potential in reducing respiratory illness related morbidity and mortality. The study was done to assess nutritional state and body composition of children with bronchiectasis and interstitial lung diseases (ChILD) and to study the effect of short course nutritional intervention program on their growth, clinical symptoms, pulmonary functions and frequency of acute exacerbations and hospitalization. Seventeen patients with bronchiectasis and thirteen patients with interstitial lung diseases and 40 healthy children as controls were enrolled. Nutritional status, chest symptoms, anthropometry, body composition, and spirometric pulmonary function were evaluated. A short course nutritional intervention program was done for patients and then they were re-evaluated.

Results

In total, 56.67% of studied patients were moderately malnourished and 23.33% were severely malnourished. A total of 66.7% of studied patients were underweight and 50% of patients had stunted growth. Anthropometric indices were significantly lower than control groups (P < 0.05). Body composition indices were lower in patients than control but not with a statistical significance. Forced vital capacity was positively correlated to body mass index (P = 0.045). Nutritional rehabilitation significantly improved patient anthropometry (weight, body mass index, height, triceps skin-fold thickness, mid arm circumference), body composition (body fat, fat free mass, and muscle mass), respiratory symptoms, and FEV1. Needs to asthma rescue medications, school absence, acute exacerbation attacks, and hospitalization were reduced.

Conclusion

Patients with bronchiectasis and interstitial lung diseases (ChILD) have malnutrition and body composition changes that improved significantly after short nutritional intervention program with significant improvement in FEV1, frequency of acute exacerbations, and hospitalization.

Obesity in cystic fibrosis

The prevalence of obesity in patients with cystic fibrosis (CF) is increasing and around one-third of adults with CF are now overweight or obese. The causes of excess weight gain in CF are likely multifactorial, including: adherence to the high-fat legacy diet, reduced exercise tolerance, therapeutic advances, and general population trends. Increased weight has generally been considered favorable in CF, correlating with improved pulmonary function and survival. While the optimal BMI for overall health in CF is unknown, most studies demonstrate minimal improvement in pulmonary function when BMI exceeds 30 kg/m2. Dyslipidemia and cardiovascular disease are important co-morbidities of obesity in the general population, but are uncommon in CF. In people with CF, obesity is associated with hypertension and higher cholesterol levels. With longer life expectancy and rising obesity rates, there may be an increase in cardiovascular disease among people with CF in coming years. Overweight CF patients are more likely to be insulin resistant, taking on features of type 2 diabetes. Treating obesity in people with CF requires carefully weighing the metabolic risks of overnutrition with the impact of low or falling BMI on lung function. This article describes current knowledge on the epidemiology, causes, consequence, and treatment of obesity in people with CF.

Body composition in individuals with cystic fibrosis

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BMI is used to characterize nutritional status but may not accurately depict body composition in CF.

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DXA and bioelectrical impedance are the most commonly used methods for assessing BC.

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Lower fat-free mass associates with worse pulmonary function and greater CF disease severity.

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Fat-free mass associates with greater bone mineral density in individuals with CF.

Because nutritional status is intimately linked with pulmonary function and survival, nutrition has been at the mainstay of cystic fibrosis (CF) care. Body Mass Index (BMI) is traditionally used to define nutritional status because of the ease with which it can be calculated, but it has a number of limitations including its inability to differentiate fat mass (FM) from lean body mass (LBM), the latter thought to confer health advantage. A number of tools are available to quantify body composition including dual-energy x-ray absorptiometry (DXA), bioelectrical impedance, MRI, CT, air displacement plethysmography, and stable isotopes, and these have been used to varying degrees in studies of CF. In CF, LBM tends to be lower for a given BMI, particularly at lower BMI. In adults, lower fat-free mass (FFM) correlates with greater CF disease severity, lower pulmonary function and higher inflammatory markers. FFM is also positively associated with greater bone mineral density, while greater FM is associated with greater loss of lumbar spine bone mineral density over 2 years. In youth, LBM is positively associated with pulmonary function. The predictive value of body composition for functional and clinical outcomes and the role of improving LBM on these outcomes remain undefined. With improvements in BMI accompanying highly-effective modulator therapy, closer evaluations of body composition may inform risk for more traditional, non-CF adult outcomes in CF.

The association between body composition, leptin levels and glucose dysregulation in youth with cystic fibrosis

BACKGROUND

Optimization of nutritional status is recommended in patients with cystic fibrosis (CF) given the association between lower body mass index (BMI) and poor clinical outcomes. However, higher BMI and body fat correlate with glucose impairment and higher leptin levels in the general population. Differences in body composition and leptin levels between the categories of glucose tolerance were assessed in youth with CF and healthy controls.

METHODS

In a cross-sectional study, 59 adolescents and young adults with CF and 15 healthy controls matched by age and gender, underwent body composition analysis using dual energy X-ray absorptiometry (DXA) and a 2-hour oral glucose tolerance test (OGTT). Measures of insulin sensitivity, β-cell insulin secretion and fasting leptin levels were obtained.

RESULTS

Of the participants with CF, 62% were classified as abnormal glucose tolerant and 22% with cystic fibrosis related diabetes (CFRD). Patients with CFRD had a lower fat mass index (FMI) z-score, wt z-score and leptin levels compared to the control group (-1.86 vs. - 0.59, p=0.01; -1.86 vs 0.44, p=<0.001 and 7.9 vs vs. 27.7 µg/L, p=0.01). Leptin correlated positively with FMI z-score, BMI, weight z-score and indices of insulin secretion. FMI z-score correlated positively with higher insulin resistance (HOMA-IR), and lower insulin sensitivity (Matsuda index) (r=0.31; p =0.01 and r=-0.29; p=0.02, respectively) in the CF group.

CONCLUSIONS

This study shows that despite new therapeutic strategies, youth with CF have lower body fat, weight z-score and leptin levels, particularly in subjects with early onset CFRD.

The Impact of the Synergistic Effect of Temperature and Air Pollutants on Chronic Lung Diseases in Subtropical Taiwan

Previous studies have suggested an association between air pollution and lung disease. However, few studies have explored the relationship between chronic lung diseases classified by lung function and environmental parameters. This study aimed to comprehensively investigate the relationship between chronic lung diseases, air pollution, meteorological factors, and anthropometric indices. We conducted a cross-sectional study using the Taiwan Biobank and the Taiwan Air Quality Monitoring Database. A total of 2889 participants were included. We found a V/U-shaped relationship between temperature and air pollutants, with significant effects at both high and low temperatures. In addition, at lower temperatures (<24.6 °C), air pollutants including carbon monoxide (CO) (adjusted OR (aOR):1.78/Log 1 ppb, 95% CI 0.98–3.25; aOR:5.35/Log 1 ppb, 95% CI 2.88–9.94), nitrogen monoxide (NO) (aOR:1.05/ppm, 95% CI 1.01–1.09; aOR:1.11/ppm, 95% CI 1.07–1.15), nitrogen oxides (NO_x) (aOR:1.02/ppm, 95% CI 1.00–1.05; aOR:1.06/ppm, 95% CI 1.04–1.08), and sulfur dioxide (SO₂) (aOR:1.29/ppm, 95% CI 1.01–1.65; aOR:1.77/ppm, 95% CI 1.36–2.30) were associated with restrictive and mixed lung diseases, respectively. Exposure to CO, NO, NO₂, NO_x and SO₂ significantly affected obstructive and mixed lung disease in southern Taiwan. In conclusion, temperature and air pollution should be considered together when evaluating the impact on chronic lung diseases.

Academy of Nutrition and Dietetics: 2020 Cystic Fibrosis Evidence Analysis Center Evidence-Based Nutrition Practice Guideline

The Academy of Nutrition and Dietetics Evidence Analysis Center conducted a systematic review of the literature to develop an evidence-based practice guideline for primary nutrition issues in cystic fibrosis (CF). This guideline is designed to complement and build upon existing evidence-based CF nutrition guidelines. The objective of this guideline was to provide recommendations for registered dietitian nutritionists in the United States delivering medical nutrition therapy to individuals with CF and their families that fill gaps in current evidence-based guidelines on topics that are crucial in order to improve health and prevent disease progression. This guideline provides 28 nutrition recommendations to guide medical nutrition therapy, including nutrition screening, nutrition assessment, and dietary intake. For topics outside the scope of this guideline, practitioners are referred to external, evidence-based recommendations. The CF landscape is evolving rapidly with breakthroughs in cystic fibrosis transmembrane regulator modulators changing CF at a cellular level. Medical nutrition therapy for individuals with CF from infancy through advanced age requires novel and individualized approaches. The Academy Evidence Analysis Library CF guidelines provide a framework for expanding upon current knowledge to determine effective nutrition strategies for individuals with CF through long and healthy futures.

The Spectrum of Fungal Colonization and Their Attributable Effects on Cystic Fibrosis Patients with Rare CFTR Genetic Mutations

Chronic airway colonization by bacteria and fungi is very common in CF patients, causing irreversible lung damage. It is known that rates of fungal infections are much lower than those of bacterial infections, however they can worsen the medical condition of CF patients. In this study, we identify the most common fungal species isolated from 31 adult CF patients in Qatar and analyze their correlation with lung function, pulmonary exacerbations, bronchial asthma, and pancreatic insufficiency. Mycological evaluation, as well as medical records, were reviewed for the patients regularly under the adult CF service at Hamad General Hospital in the period between 2017–2019. All CF patients included in this study carry rare CFTR mutations. The majority of those patients (n = 25) carried the c.3700A>G; I1234V mutation, whereas three patients carried the heterozygous mutation (c.1657C>T and c.1115A>T) and the remaining three carried the homozygous mutation (c.920G>A). Twenty-two of the adult CF participants (70.9%) were colonized with fungal species regardless of the type of the CFTR mutation. Candida and Aspergillus species were the most common, colonizing 81% and 45% of the patients, respectively. For Candida colonized patients, Candida dubliniensis was the most frequently reported species (55.6%), whereas Aspergillus fumigatus colonization was the most common (50.0%) among Aspergillus colonized patients. These identified fungal pathogens were associated with poor lung function, pancreatic insufficiency, and asthma in this cohort. Such colonization could possibly aggravate the most known CF complications, notably pulmonary exacerbations, asthma, and pancreatic insufficiency.

Effect of transfer from a pediatric to adult cystic fibrosis center on clinical status and hospital attendance

AIM

Transfer from pediatric to adult services could lead to clinical deterioration, few studies have examined this. We sought to examine the clinical impact of a structured individualized transition and transfer process in patients with cystic fibrosis (CF).

METHODS

Medical records of all patients with CF in Western Australia who transferred from a pediatric center (Princess Margaret Hospital for Children) to an adult CF center (Sir Charles Gairdner Hospital) between 2008 and 2012 were reviewed. Data were extracted for 2 years before and after transfer. The number of CF outpatient visits, inpatient days, and home intravenous antibiotic therapy (HIVT) days were recorded at yearly intervals before and after transfer. Sputum culture results at transfer were collected. All respiratory function and anthropometric data over the 4 years were extracted.

RESULTS

Forty-two patients with CF were transferred between 2008 and 2012. The mean age at transfer was 18.9 years (range 17-22). Compared to 1-year pre-transfer, the frequency of outpatient visits at 1- and 2-year post-transfer increased. After transfer, there was no change in BMI, HIVT days, or inpatient days, and no acceleration in the expected decline in FEV1.

CONCLUSION

This study found that transfer from a pediatric to an adult CF center using a structured, individualized transition and transfer process was not associated with accelerated clinical deterioration.

Factors Influencing Lung Function in Patients with Cystic Fibrosis in Western Romania

PURPOSE

The aim of this cross-sectional study was to identify the major factors influencing pulmonary function in CF patients from western side of Romania.

PATIENTS AND METHODS

The study enrolled 51 patients with CF between the ages of 6 and 27.8 years who were monitored at regular visits to the National Cystic Fibrosis Centre and Pius Branzeu County Hospital in Timisoara, Romania, over a period of 2 years. The relationships between lung function, as measured by forced expiratory volume in 1 s (FEV1), with patient age, sex, body mass index (BMI), pancreatic insufficiency (PI), microbial infection, CF-related diabetes (CFRD), CF-associated liver disease (CFLD), and physical activity <30 min/day, were evaluated by multivariate regression analysis.

RESULTS

The results showed that FEV1 was 0.32% higher for each increase in percentile of BMI (95% confidence interval: 0.034-0.619). In addition, mean FEV1 was 1.52% lower with every year rise of age. PI and female sex increased the risk of impaired lung function (FEV1 <60%). The factors most closely correlated with pulmonary function in pediatric CF patients were current age (negative) and BMI (positive).

CONCLUSION

The findings of this study, in combination with what is known from other studies in CF, suggest that a better nutritional status and infection prophylaxis should be part of a comprehensive clinical management strategy for pediatric CF in Romania.

Relationships between plasma apelin and adiponectin with normal weight obesity, body composition, and cardiorespiratory fitness in working adults

Background

A significant proportion of adults have normal weight obesity (NWO), defined as a normal body mass index (BMI) but disproportionately high body fat percentage. Individuals with NWO may have increased risk of cardiometabolic disorders and lower exercise tolerance, but it is unclear if this obesity phenotype is linked with dysregulated production of adipokines or myokines such as adiponectin and apelin, respectively.

Methods

This cross-sectional, secondary analysis included 177 working adults (mean age 49.6 ± 9.9 yrs, 64% female). Plasma high-molecular weight adiponectin and apelin levels were measured by ELISA. Body composition and fat distribution were assessed using dual energy X-ray absorptiometry. Exercise tolerance (VO₂ maximum) was determined by treadmill testing. NWO was defined as a BMI <25 kg/m² and body fat >30% for women or >23% for men. Participants were categorized as lean, NWO, or overweight-obese.

Results

A total of 14.7% of subjects were categorized as lean, 23.7% as having NWO, and 61.6% as having overweight-obesity. Plasma adiponectin levels were elevated in the overweight-obesity group (P < 0.05) compared to the lean and NWO groups, which did not differ from each other (P > 0.05). Adiponectin concentrations were inversely associated with BMI, fat mass, fat mass percent, visceral fat, and trunk to leg fat ratio and positively associated with leg fat mass (all P < 0.001). Plasma apelin levels were similar between the three body composition groups (P < 0.05) and were not significantly associated with any body composition indices. Apelin concentrations were inversely related to VO₂ maximum (β = −0.03 ± 0.01, p = 0.002).

Conclusion

Plasma adiponectin and apelin levels did not distinguish between lean and NWO groups. Positive relationships with leg fat mass and adiponectin suggest the importance of assessing body composition and fat distribution when studying adipokines and cardiometabolic disorders. Further investigations are needed to understand relationships between exercise, body composition, and apelin secretion.

The effect of an intensive residential rehabilitation program on body composition in patients with cystic fibrosis

The pulmonary function of patients with cystic fibrosis (CF) is associated with nutritional status not only expressed as body mass index (BMI) but also as fat-free mass index (FFMI). This study evaluated the effect of a residential rehabilitation program on nutritional status (BMI, FFMI). The rehabilitation program provided supervised respiratory and nutritional treatment and daily physical activity for 3 weeks (median stay 20 (19-25) days). At the start and the end of the program, weight, height, pulmonary function, and body composition using dual-energy X-ray absorptiometry were prospectively collected. Supervised weighed food records were obtained, and physical activity intensity was measured using a SenseWear Pro3 Armband. CF-related complications were collected from the patient. Thirty-four patients (21 males, median age 18 years old (12-27)) were included. The diet contained a median of 30 EN% fat, 16 EN% protein, and 52 EN% of carbohydrates. A significant median weight gain (+1.45 kg (0.58; 2.6) (p < 0.0001) and a significant increase in BMI (+0.24 kg/m² (0.11; 0.38)) (p < 0.0001), FFMI (+0.26 kg/m² (0.01; 0.55)) (p < 0.0001), and FMI (+0.19 kg/m² (0.04; 0.41)) (p < 0.0001) were obtained.Conclusion: A short rehabilitation program in individuals with CF between 6 and 40 years old is able to improve nutritional status and body composition.Trial registration: NCT04527796 What is Known: • Fat-free mass depletion is frequently present in CF. • In CF pulmonary function is associated with nutritional status measured as body mass index but also fat-free mass index. What is New: • Nutritional status and body composition improve significantly after a short-term rehabilitation program. • The rehabilitation program was able to improve nutritional outcome even with a diet containing less fat than currently advised in the guidelines.

Comparison of body composition parameters in the study of the association between body composition and pulmonary function

Background

The excess adiposity, even in the absence of diseases, is responsible for a decline in pulmonary function, which is considered a predictor of mortality and a risk factor for diseases in several epidemiological studies. However, studies on the association between obesity and pulmonary function have found only few associations or inconclusive results. The aim of the study is to evaluate the association between body composition and spirometric parameters, comparing simple obesity measures such as body mass index (BMI) and waist circumference with more precise body composition measurements such as dual-energy X-ray absorptiometry (DXA) and air-displacement plethysmography (BOD POD).

Methods

This is an observational, cross-sectional study that used data from the 1978/79 Ribeirão Preto birth cohort (São Paulo, Brazil). The study included 1746 participants from the 5th follow-up of the cohort. Linear regressions were calculated to evaluate the association between BMI, waist circumference, waist–height ratio (WHtR), BOD POD- and DXA-measured fat mass percentage, and spirometric parameters FEV1, and FVC.

Results

For every 1-kg/m² BMI increase, FVC decreased by 13 ml in males and by 6 ml in females and FEV1 decreased by 11 ml and 5 ml, respectively. Regarding body composition measurements, for a 1% increase in fat mass assessed by BOD POD, FVC decreased by 16 ml in males and by 8 ml in females and FEV1 decreased by 13 ml and 7 ml, respectively. Hence, negative associations between body measurements and FEV1 and FVC were observed in both genders, especially when using the fat mass measurement and were more expressive in men.

Conclusion

The anthropometric and body composition parameters were negatively associated with the spirometric variables FVC and FEV1. We have also observed that simple measures such as waist-height ratio were sufficient to detect the association of body composition with pulmonary function reduction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01543-1.

The prevalence of aberrations in body composition in pediatric cystic fibrosis patients and relationships with pulmonary function, bone mineral density, and hospitalizations

BACKGROUND

Body mass index (BMI) correlates with clinical outcomes in cystic fibrosis but has limitations.  Body composition aberrations in CF are multifactorial. We sought to evaluate body composition and relationships with pulmonary function, bone health, and hospital admissions. Other aims included defining body composition indices in a cohort of children with CF.

METHODS

We conducted a retrospective review of patients with CF, age 8-18 years, seen at Nationwide Children's Hospital (2015-2020). Indices of body composition measured by dual-energy x-ray absorptiometry(DXA) scans.  Data included fat mass, fat-free mass (FFM), forced expiratory volume in one second (FEV1%), bone mineral density (BMD), and hospital admissions. NWA was defined as BMI 5^th-85^th percentile, body fat percentage >85^th percentile. FFMD defined as FFMI <10^th percentile.

STATISTICS

T-tests compared NWA, FFMD and clinical measurements. Pearson correlations analyzed fat-free mass index (FFMI), fat mass index (FMI), BMI and clinical measurements.

RESULTS

This study included 114 patients.  Mean age 12 years, 72 female. A high prevalence of FFMD existed (n=66, 38.6%).  FMI and FFMI correlated with FEV1% (r: 0.23, p:0.01, r: 0.36, p<0.001, respectively) and BMD (r: 0.29, p:0.002). FMI and hospital admissions were related (r:-0.23,p:0.01). FFMD was associated with 9.5% lower FEV1% (p=0.001) and lower BMD Z-score by 1.1 (p<0.001) when compared to no FFMD.

CONCLUSION

This cohort of children with CF had a high prevalence of FFMD and low prevalence of NWA.  FFMD was associated with worsened clinical measurements. Patients with FFMD need additional exercise or nutritional intervention. Heterogeneity of body composition definitions creates need for more research.

Lumacaftor/ivacaftor-associated health stabilisation in adults with severe cystic fibrosis

Introduction

Lumacaftor/ivacaftor (LUM/IVA) has been shown to improve clinical outcomes in cystic fibrosis (CF) patients homozygous for Phe508del with forced expiratory volume in 1 s (FEV₁) % pred >40%. We assessed the clinical utility of LUM/IVA in all eligible adult CF patients with FEV₁ % pred <40% treated for at least 1 year under a single-centre managed access programme.

Methods

Following clinical optimisation, eligible patients (n=40) with FEV₁ % pred <40% were commenced on LUM/IVA and monitored for tolerance and clinical outcomes, including health service utilisation, pulmonary function, weight and body composition. 24 patients reached 1 year of treatment by the time of evaluation. Six patients discontinued due to adverse events (five for increased airways reactivity) and three underwent lung transplantation.

Results

In comparison with the year prior to LUM/IVA commencement, significant reductions (median per year) were observed in the treatment year in the number of pulmonary exacerbations requiring hospitalisation (from 3 to 1.5; p=0.0002), hospitalisation days (from 27 to 17; p=0.0002) and intravenous antibiotic (IVAB) usage days (from 45 to 27; p=0.0007). Mean±sd change in FEV₁ % pred was −2.10±1.18% per year in the year prior, with the decline reversed in the year following (+1.45±1.13% per year; p=0.035), although there was significant heterogeneity in individual responses. Mean±sd weight gain at 1 year was 2.5±4.1 kg (p=0.0007), comprising mainly fat mass (mean 2.2 kg). The proportion of patients severely underweight (body mass index <18.5 kg·m⁻²) decreased from 33% at baseline to 13% at 1 year (p=0.003).

Conclusion

This real-world evaluation study demonstrated benefits over several clinical domains (infective exacerbations requiring hospitalisation, IVABs, pulmonary function decline and nutritional parameters) in CF patients with severe lung disease.

In adults with severe cystic fibrosis lung disease, 1 year of treatment with lumacaftor/ivacaftor was associated with reduced infective exacerbations, days of intravenous antibiotics and rate of pulmonary function decline, and improved nutritional statushttps://bit.ly/2I07suR

Body composition and weight changes after ivacaftor treatment in adults with cystic fibrosis carrying the G551 D cystic fibrosis transmembrane conductance regulator mutation: A double-blind, placebo-controlled, randomized, crossover study with open-label extension

OBJECTIVES

In patients with cystic fibrosis (CF) who carry the G551D mutation, treatment with ivacaftor improves lung function and weight; however, short- and long-term impacts on body composition have not been well studied.

METHODS

Twenty adults with CF carrying the G551D mutation (mean ± standard deviation body mass index [BMI] 23.3 ± 4.3 kg/m²) were recruited for a single-center, double-blind, placebo-controlled, 28-d, crossover study of ivacaftor, followed by an open-label extension (OLE) for 5 mo. Eleven patients underwent measurements 2 y later. The study variables included weight, BMI, and body composition (including fat-free mass [FFM] and fat mass).

RESULTS

After 28 d of treatment with ivacaftor, weight increased by 1.1 ± 1.3 kg, BMI by 0.4 ± 0.5 kg/m², and FFM by 1.1 ± 1.2 kg (all P < .005) with no change in fat mass. Differences between 28-d changes on ivacaftor and placebo were not statistically significant. In the following 5 mo of the OLE, there were significant increases in weight (1.2 ± 1.9 kg; P < .05) and fat mass (1.5 ± 1.9 kg; P < .01), but not in FFM. Between baseline and the end of the OLE, the total weight gain was 2.5 ± 2.4 kg (P < .005), comprised of 0.9 ± 1.5 kg FFM (P < .05) and 1.6 ± 1.8 kg fat mass (P < .005). For the 11 participants who were followed for a further 2 y, no further changes in mean weight, BMI, or body composition parameters between 6 mo and 2 y later were observed.

CONCLUSIONS

Small gains were seen in FFM in the first month of ivacaftor treatment. Weight, BMI, and fat-mass gains in the first 6 mo on ivacaftor plateaued by 2.5 y. The metabolic and clinical consequences of weight and fat-mass gains remain to be determined.

Assessment of Distinct Electrophysiological Parameters in Rectal Biopsies for the Choice of the Best Diagnosis/Prognosis Biomarkers for Cystic Fibrosis

Most cases of Cystic Fibrosis (CF) are diagnosed early in life. However, people with atypical CF forms pose diagnosis dilemmas, requiring laboratory support for diagnosis confirmation/exclusion. Ex vivo analysis of fresh rectal biopsies by Ussing chamber has been the best discriminant biomarker for CF diagnosis/prognosis so far. Here we aimed to evaluate different electrophysiological parameters from Ussing chamber analysis of rectal biopsies from people with CF (PwCF) to establish the one with highest correlations with clinical features as the best CF diagnosis/prognosis biomarker. We analyzed measurements of CFTR-mediated Cl- secretion in rectal biopsies from 143 individuals (∼592 biopsies), the largest cohort so far analyzed by this approach. New parameters were analyzed and compared with the previous biomarker, i.e., the IBMX (I)/Forskolin (F)/Carbachol (C)-stimulated short-circuit current (I'sc-I/F/C). Correlations with clinical features showed that the best parameter corresponded to voltage measurements of the I/F + (I/F/CCH) response (VI/F+I/F/C), with higher correlations vs. I'sc-I/F/C for: sweat chloride (59 vs. 52%), fecal elastase (69 vs. 55%) and lung function, measured by FEV1 (27 vs. 20%). Altogether data show that VI/F+I/F/C is the most sensitive, reproducible, and robust predictive biomarker for CF diagnosis/prognosis effectively discriminating classical, atypical CF and non-CF groups.

The Association of Grip Strength, Body Mass Index, and Lung Function in Youth with Cystic Fibrosis

Compared with body mass index (BMI), lean body mass and fat-free mass are strongly associated with lung function in children and adolescents with cystic fibrosis (CF). Methods of measuring body composition in youth with CF are often unreliable, expensive, or not clinically feasible. Grip strength (GS), a measure of muscle function, is used as a surrogate for muscle mass and is an indicator of nutrition status. This quality improvement project explored the feasibility of measuring GS in medically stable youth with CF, aged 6-21 years. A total 361 GS measurements were performed by using a digital hand dynamometer in youth from a single CF center. Using reference tables that were created for this project by merging data from the 2011-2012 and 2013-2014 National Health and Nutrition Examination Surveys, youth with CF were found to be weaker than age- and gender-matched peers, even when controlled for differences in size. A positive association (P < .001) was found between GS percentile and lung function, as measured by forced expiratory volume in 1 second percent predicted (FEV1pp). Statistical analysis revealed that both BMI percentile and absolute GS (AGS) percentile were positively associated with FEV1pp and with each other, primarily at the lower levels of BMI percentile (<50%) and AGS percentile (<50%). GS may provide a reliable, less expensive, and clinically feasible alternative to body composition measurements in monitoring nutrition status in youth with CF, especially in youth whose BMI is in the <50th percentile.

Body composition and lung function in adults with Cystic Fibrosis

The study aimed to assess: (1) differences in nutritional status and lung function between CF patients and the control group; (2) differences in body composition and lung function between groups of patients with CF designated by type of mutation; (3) the relationship between lung function and body composition in CF patients.

We studied 37 CF patients aged 19 to 51 years, and 41 healthy non-CF volunteers. Nutritional status was evaluated based on the BMI and the bioelectrical impedance analysis. The lung function was described by FEV1%. CF patients were classified according to the CFTR genotype based on five classes of mutations. BMI were lower in CF patients compared to reference group (women: Z = 3.76, p <0.001, men: Z = 3.06, p = 0.002). CF patients had a lower mean content of particular body components, as well as FEV1% values. BMI differed significantly depending on the type of mutation in females (H = 10.33, p = 0.006) and males (H = 8.26, p = 0.016). The lowest values of BMI were observed in the group of patients with severe types of mutations. Also, variables describing body composition were statistically significantly lower in patients with a severe type of mutations. The CFTR gene mutation type statistically significantly differentiated FEV1% (H = 23.22, p <0.000). The results of the logistic regression analysis showed that the likelihood of dropping FEV1% below the norm was twice as high in undernourished females and males. To assess the nutritional status of CF patients, more informative methods describing the proportions of body components are required.

Nutritional assessment in adults with cystic fibrosis

OBJECTIVES

Clinical experience with patients with cystic fibrosis (CF) suggests a nutritional risk in this population. In addition to the lung pathology, a main pathophysiologic concern is the viscous mucus blocking pancreatic ducts, leading to reduced production of pancreatic enzymes. Therefore, maldigestion and consequently malabsorption (particularly fat and fat-soluble vitamins) occur, resulting in steatorrhea, vitamin deficiencies, and subsequently manifest malnutrition. The aim of this study was to investigate the nutritional status and determine the prevalence of malnutrition in an adult Swiss CF cohort.

METHODS

This was an observational cohort study in which the nutritional status and dietary habits of patients with CF and healthy controls were compared. Assessment was based on the nutritional risk screening (NRS-2002), dietary habits (7-d dietary record), body composition (bioelectrical impedance analysis), anthropometrics, resting energy expenditure (REE; indirect calorimetry), and physical or mental function (hand-grip strength, Short Form-36 v2).

RESULTS

Nineteen patients (15 men, mean age 32 y) and 15 controls (8 men, mean age 49 y) were included. Eight patients (42%) were at nutritional risk (NRS-2002 ≥3). Patients had higher energy intake/body weight (P = 0.021) with lower body fat percentage (P < .001), body mass index (P = 0.030), and physical/mental health scores (P < 0.001) than controls. Energy intake was higher than REE in patients (P = 0.003), but not in controls (P = 0.373).

CONCLUSIONS

Prevalence of malnutrition was high in this CF cohort, coinciding with low body fat percentage and low body mass index despite high energy and protein intake. Energy requirements of patients with CF should be estimated as approximately twice the Harris-Benedict REE and 1.7 times indirect calorimetry REE, while ensuring adequate intake of pancreatic enzymes.

HDAC6 depletion improves cystic fibrosis mouse airway responses to bacterial challenge

The hypothesis of this study was that Hdac6 depletion would restore cystic fibrosis (CF) responses to bacterial challenge to more wild type profiles using a CF mouse model. CF mice harboring the F508del Cftr mutation respond to bacterial challenge with 25,000 CFU Pseudomonas aeruginosa embedded into agarose beads to slow clearance. CF mice respond significantly more aggressively to this challenge compared to WT mice with respect to bacterial clearance, weight loss, neutrophil recruitment, and MIP-2 production. Depletion of Hdac6 expression in the CF mice (CF/Hdac6) significantly improves these responses to more WT levels. Weight loss in response to infection is most severe in CF mice and significantly attenuated in CF/Hdac6 mice. Bacterial levels are reduced at a faster rate in CF/Hdac6 mice compared to CF mice where infection persists. Percent neutrophils in lung lavage fluid post-infection are significantly higher in CF mice, but returned to WT levels with CF/Hdac6 mice. Similarly, CF Mip-2 levels are restored to WT levels in the absence of Hdac6 expression. These data demonstrate that Hdac6 depletion restores CF responses to bacterial challenge to WT-like profiles and offer a potential therapeutic avenue for addressing inflammation and infection in CF airways independently of Cftr correction.

Non-fasting bioelectrical impedance analysis in cystic fibrosis: Implications for clinical practice and research

BACKGROUND

Nutritional status affects pulmonary function in cystic fibrosis (CF) patients and can be monitored by using bioelectrical impedance analysis (BIA). BIA measurements are commonly performed in the fasting state, which is burdensome for patients. We investigated whether fasting is necessary for clinical practice and research.

METHODS

Fat free mass (FFM) and fat mass (FM) were determined in adult CF patients (n = 84) by whole body single frequency BIA (Bodystat 500) in a fasting and non-fasting state. Fasting and non-fasting BIA outcomes were compared with Bland-Altman plots. Pulmonary function was expressed as Forced Expiratory Volume at 1 s percentage predicted (FEV1%pred). Comparability of the associations between fasting and non-fasting body composition measurements with FEV1%pred was assessed by multiple linear regression.

RESULTS

Fasting FFM, its index (FFMI), and phase angle were significantly lower than non-fasting estimates (-0.23 kg, p = 0.006, -0.07 kg/m², p = 0.002, -0.10°, p = 0.000, respectively). Fasting FM and its index (FMI) were significantly higher than non-fasting estimates (0.22 kg, p = 0.008) 0.32%, p = 0.005, and 0.07 kg/m², (p = 0.005). Differences between fasting and non-fasting FFM and FM were <1 kg in 86% of the patients. FFMI percentile estimates remained similar in 83% of the patients when measured after nutritional intake. Fasting and non-fasting FFMI showed similar associations with FEV1%pred (β: 4.3%, 95% CL: 0.98, 7.70 and β: 4.6%, 95% CI: 1.22, 8.00, respectively).

CONCLUSION

Differences between fasting and non-fasting FFM and FM were not clinically relevant, and associations with pulmonary function remained similar. Therefore, BIA measurements can be performed in a non-fasting state.

Highlights from the nutrition guidelines for cystic fibrosis in Australia and New Zealand

Optimal nutrition care is important in the management of cystic fibrosis (CF). This paper summarises the '2017 Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand (NZ)'. CF dietitians formulated 68 practice questions which were used to guide a systematic literature search and review of the evidence for nutrition in CF. Identified papers underwent quality and evidence assessment using the American Dietetic Association quality criteria checklist and the National Health and Medical Research Council of Australia (NHMRC) rankings. Evidence statements, graded recommendations and practice points were developed covering core nutrition topics (assessment and nutrition interventions including oral, enteral and micronutrient supplementation); nutrition-related co-morbidities (including pancreatic insufficiency, CF-related diabetes, bone health and distal intestinal obstruction syndrome); and key new topic areas (genetic modulator therapies, overweight/obesity and complementary therapies). This paper showcases highlights from the guidelines, focussing on new topic areas and geographic and climate considerations for vitamin D, salt and hydration.

Visceral adipose tissue is associated with poor diet quality and higher fasting glucose in adults with cystic fibrosis

BACKGROUND

Body fat distribution and diet quality influence clinical outcomes in general populations but are understudied in individuals with cystic fibrosis (CF). The aim of this pilot study was to assess body fat distribution and diet quality in relation to fasting glucose and lung function in adults with CF.

METHODS

Subjects were 24 adults (ages 18-50) with CF and 25 age-matched controls. The Healthy Eating Index 2015 (HEI-2015) was calculated from 3-day food records and data were adjusted per 1000 kcal. Whole and regional body composition, including visceral adipose tissue (VAT), was assessed by dual energy X-ray absorptiometry.

RESULTS

Subjects with CF reported more added sugar intake [26.1 (IQR 18.1) vs. 12.9 (12.5) g/1000 kcal, p < 0.001] and had lower HEI-2015 scores [48.3 (IQR 9.9) vs. 63.9 (27.3), p < 0.001] compared to controls. There were no differences in BMI, total body fat, or lean body mass (LBM) between subjects with CF and controls (p > 0.05 for all), although subjects with CF had higher VAT than control subjects [0.3 (IQR 0.3) vs 0.1 (0.3) kg, p = 0.02]. Among subjects with CF, VAT was positively associated with added sugar intake (p < 0.001) and fasting blood glucose (p = 0.04). Lung function was positively associated with BMI (p = 0.005) and LBM (p = 0.03) but not with adiposity indicators.

CONCLUSIONS

These novel data link body fat distribution with diet quality and fasting glucose levels in adults with CF, whereas LBM was associated with lung function. This study highlights the importance of increasing diet quality and assessing body composition and fat distribution in the CF population.

Fat-free mass index is superior to body mass index as a novel risk factor for prolonged air leak complicating video-assisted thoracoscopic surgery lobectomy for non-small-cell lung cancer

Background

To evaluate whether fat-free mass index (FFMI) could be predictive of prolonged air leak (PAL) complicating video-assisted thoracoscopic (VATS) lobectomy for non-small-cell lung cancer (NSCLC).

Methods

A retrospective study was conducted on the prospectively-maintained database in our institution between January 2015 and July 2017. The gender-specific median values of FFMI for males and females were applied as their respective cutoffs to stratify patients into low-FFMI group and high-FFMI group in initial univariable analyses. An effective multivariable logistic-regression analysis was then performed to demonstrate the predictive value of dichotomized FFMI.

Results

There were 1,091 surgical patients with NSCLC included (616 males and 475 females), with a PAL incidence of 14.6%. The median FFMI values among males and females were 17.3 and 14.6 kg/m², respectively. PAL cases in both male (16.9±1.5 vs. 17.4±1.5 kg/m²; P=0.002) and female (14.0±0.9 vs. 14.6±1.1 kg/m²; P<0.001) groups had a significantly lower mean FFMI than that of non-PAL cases. The incidence of PAL was significantly increased in male patients with FFMI <17.3 kg/m² (23.7% vs. 14.3%; P=0.003) and female patients with FFMI <14.6 kg/m² (12.7% vs. 5.0%; P=0.003). Lower dichotomized FFMI was also significantly associated with prolonged time to air leak cessation and length of stay (LOS). Finally, multivariable logistic-regression analysis indicated that lower dichotomized FFMI [odds ratio (OR) =1.98; 95% confidence interval (CI): 1.33-2.96; P=0.001] could independently predict the occurrence of PAL.

Conclusions

FFMI acts as an excellent categorical risk factor for PAL complicating VATS lobectomy and shows a much superior significance than body mass index (BMI) in terms of the prediction of PAL.