Survival of Patients with Cystic Fibrosis Depending on Mutation Type and Nutritional Status

Survival of people with cystic fibrosis in Australia

Survival statistics, estimated using data from national cystic fibrosis (CF) registries, inform the CF community and monitor disease progression. This study aimed to estimate survival among people with CF in Australia and to identify factors associated with survival. This population-based cohort study used prospectively collected data from 23 Australian CF centres participating in the Australian CF Data Registry (ACFDR) from 2005-2020. Period survival analysis was used to calculate median age of survival estimates for each 5-year window from 2005-2009 until 2016-2020. The overall median survival was estimated using the Kaplan-Meier method. Between 2005-2020 the ACFDR followed 4,601 people with CF, noting 516 (11.2%) deaths including 195 following lung transplantation. Out of the total sample, more than half (52.5%) were male and 395 (8.6%) had undergone lung transplantation. Two thirds of people with CF (66.1%) were diagnosed before six weeks of age or by newborn/prenatal screening. The overall median age of survival was estimated as 54.0 years (95% CI: 51.0-57.04). Estimated median survival increased from 48.9 years (95% CI: 44.7-53.5) for people with CF born in 2005-2009, to 56.3 years (95% CI: 51.2-60.4) for those born in 2016-2020. Factors independently associated with reduced survival include receiving a lung transplant, having low FEV₁pp and BMI. Median survival estimates are increasing in CF in Australia. This likely reflects multiple factors, including newborn screening, improvement in diagnosis, refinements in CF management and centre-based multidisciplinary care.

Association between phenotypic and genotypic characteristics and disease severity in individuals with cystic fibrosis

OBJECTIVE

To analyze the association between phenotypic and genotypic characteristics and disease severity in individuals with cystic fibrosis treated at a reference center in Minas Gerais, Brazil.

METHODS

This is a retrospective study that collected clinical and laboratory data, respiratory and gastrointestinal manifestations, type of treatment, Shwachman-Kulczycki score, and mutations from the patients' medical records.

RESULTS

The sample included 50 participants aged one to 33 years, 50% of whom were female. Out of the one hundred alleles of the Cystic Fibrosis Transmembrane Conductance Regulator gene, the most prevalent mutations were DeltaF508 (45%) and S4X (18%). Mutation groups were only associated with pancreatic insufficiency (p=0.013) and not with disease severity (p=0.073). The latter presented an association with colonization by Pseudomonas aeruginosa and Staphylococcus aureus (p=0.007) and with underweight (p=0.036). Death was associated with age at diagnosis (p=0.016), respiratory symptomatology (p=0.013), colonization (p=0.024), underweight (p=0.017), and hospitalization (p=0.003).

CONCLUSIONS

We could identify the association of mutations with pancreatic insufficiency; the association of Staphylococcus aureus colonization and underweight with disease severity; and the lack of association between mutations and disease severity. Environmental factors should be investigated more thoroughly since they seem to have an important effect on disease severity.

The determinants of survival among adults with cystic fibrosis-a cohort study

BACKGROUND

Cystic fibrosis (CF) is one of the most common autosomal recessive diseases. Factors contributing to disease exacerbations and survival rate of CF patients are type of mutation in the CFTR gene, poor nutritional status, lung failure, and infection development by Pseudomonas aeruginosa. The study aimed to evaluate the relationship between the severity of mutation, nutritional status, lung function, and Pseudomonas aeruginosa prevalence and survival rate in adult patients with cystic fibrosis.

METHODS

A study of 124 (68 ♀ and 56 ♂) adults with CF aged 18-51 years were evaluated for (a) type of mutation in the CFTR gene, (b) nutritional status (BMI), (c) lung function (FEV₁%), and (d) Pseudomonas aeruginosa prevalence. For statistical calculations, Kaplan-Meier analysis of survival, chi-squared test for multiple samples, and logistic regression were used.

RESULTS

The type of mutation (χ² = 12.73, df = 3, p = 0.005), FEV₁% (χ² = 15.20, df = 2, p = 0.0005), Pseudomonas aeruginosa prevalence (χ² = 11.48, df = 3, p = 0.009), and BMI (χ² = 31.08, df = 4, p < 0.000) significantly differentiated the probability of survival of patients with CF. The shortest life expectancy was observed in patients with a severe type of mutation on both alleles, FEV₁% < 40, subjects in whom Pseudomonas culture was extensively drug-resistant or pandrug-resistant, and patients whose BMI was lower than 18.5 kg/m². The period from 30 to 40 years of age was the most critical in CF adults' lifespan. The risk of adults with CF death doubled with Pseudomonas aeruginosa prevalence (OR = 2.06, 95% CI 1.29; 2.28) and eightfold when the bacteria acquired antibiotic resistance (OR = 8.11, 95% CI 1.67; 38.15).

CONCLUSIONS

All factors included in the study were significantly related to the survival rate of patients with cystic fibrosis.

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.

Effect of CFTR Modulators on Anthropometric Parameters in Individuals with Cystic Fibrosis: An Evidence Analysis Center Systematic Review

There is a strong positive association between nutrition status and lung function in cystic fibrosis (CF). Improvements in clinical care have increased longevity for individuals with CF, and it is unknown how cystic fibrosis transmembrane regulator (CFTR) modulation therapy affects nutrition status over time. The objective of this systematic review of the literature was to examine anthropometric (height, weight, and body mass index [BMI; calculated as kg/m²]) and body composition outcomes of CFTR modulation therapy. A literature search of Medline (Ovid), Embase, and CINAHL (EBSCO) databases was conducted for randomized controlled trials examining the effect of CFTR modulation therapy on anthropometric and body composition parameters, published in peer-reviewed journals from January 2002 until May 2018. Articles were screened, data were synthesized qualitatively, and evidence quality was graded by a team of content experts and systematic review methodologists. Significant weight gain with ivacaftor was noted in children and adults with at least 1 copy of G551D mutation. In adults with at least 1 copy of R117H the effect of ivacaftor on BMI was not significant. Effects on BMI were mixed in adults with class II mutations taking ivacaftor with lumacaftor. There was no significant change in BMI in children homozygous for F508del who took ivacaftor with tezacaftor. Elexacaftor-tezacaftor-ivacaftor increased BMI and body weight in individuals 12 years of age and older who were hetero- or homozygous for the F508del mutation. The effect of CFTR modulation therapy on anthropometric parameters depends on the genetic mutation and the type of modulation therapy used. More research is needed to understand the long-term clinical impact of these drugs on nutritional status, including body composition and the role of dietary intake.

Molecular and Microbial Microenvironments in Chronically Diseased Lungs Associated with Cystic Fibrosis

To visualize the personalized distributions of pathogens and chemical environments, including microbial metabolites, pharmaceuticals, and their metabolic products, within and between human lungs afflicted with cystic fibrosis (CF), we generated three-dimensional (3D) microbiome and metabolome maps of six explanted lungs from three cystic fibrosis patients. These 3D spatial maps revealed that the chemical environments differ between patients and within the lungs of each patient. Although the microbial ecosystems of the patients were defined by the dominant pathogen, their chemical diversity was not. Additionally, the chemical diversity between locales in the lungs of the same individual sometimes exceeded interindividual variation. Thus, the chemistry and microbiome of the explanted lungs appear to be not only personalized but also regiospecific. Previously undescribed analogs of microbial quinolones and antibiotic metabolites were also detected. Furthermore, mapping the chemical and microbial distributions allowed visualization of microbial community interactions, such as increased production of quorum sensing quinolones in locations where Pseudomonas was in contact with Staphylococcus and Granulicatella, consistent with in vitro observations of bacteria isolated from these patients. Visualization of microbe-metabolite associations within a host organ in early-stage CF disease in animal models will help elucidate the complex interplay between the presence of a given microbial structure, antibiotics, metabolism of antibiotics, microbial virulence factors, and host responses.IMPORTANCE Microbial infections are now recognized to be polymicrobial and personalized in nature. Comprehensive analysis and understanding of the factors underlying the polymicrobial and personalized nature of infections remain limited, especially in the context of the host. By visualizing microbiomes and metabolomes of diseased human lungs, we reveal how different the chemical environments are between hosts that are dominated by the same pathogen and how community interactions shape the chemical environment or vice versa. We highlight that three-dimensional organ mapping methods represent hypothesis-building tools that allow us to design mechanistic studies aimed at addressing microbial responses to other microbes, the host, and pharmaceutical drugs.

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.

Impact of cystic fibrosis on birthweight: a population based study of children in Denmark and Wales

BACKGROUND

Poor growth during infancy and childhood is a characteristic feature of cystic fibrosis (CF). However, the impact of CF on intrauterine growth is unclear. We studied the effect of CF on birth weight in Denmark and Wales, and assessed whether any associations are due to differences in gestational age at birth.

METHODS

We conducted national registry linkage studies in two countries, using data for 2.2 million singletons born in Denmark (between 1980 and 2010) and Wales (between 1998 and 2015). We used hospital inpatient and outpatient data to identify 852 children with CF. Using causal mediation methods, we estimated the direct and indirect (via gestational age) effect of CF on birth weight after adjustment for sex, parity and socioeconomic background. We tested the robustness of our results by adjusting for additional factors such as maternal smoking during pregnancy in subpopulations where these data were available.

RESULTS

Babies with CF were more likely to be born preterm and with low birth weight than babies with no CF (12.7% vs 5% and 9.4% vs 5.8% preterm; 11.9% vs 4.2% and 11% vs 5.4% low birth weight in Denmark and Wales, respectively). Using causal mediation methods, the total effect of CF on birth weight was estimated to be -178.8 g (95% CI -225.43 to -134.47 g) in the Danish population and -210.08 g (95% CI -281.97 to -141.5 g) in the Welsh population. About 40% of this effect of CF on birth weight was mediated through gestational age.

CONCLUSIONS

CF significantly impacts on intrauterine growth and leads to lower birth weight in babies with CF, which is only partially explained by shorter gestation.