Prevalence, risk factors and outcomes of cardiac disease in cystic fibrosis: a multinational retrospective cohort study.

BACKGROUND: Although people living with cystic fibrosis (PwCF) often have some risk factors for cardiovascular disease, including diabetes and chronic inflammation, little is known about the long-term cardiac risk in this condition. We aimed to determine the characteristics, rates and outcomes for cardiac disease in CF. METHODS: We looked at rates and outcomes for cardiac disease in 5649 adult PwCF in the UK CF Registry and 6265 adult PwCF in TriNetX (a global federated database of electronic healthcare record data). We used propensity matching to compare risk of major adverse cardiac events (MACE) (myocardial infarction, left-sided heart failure and atrial fibrillation) in PwCF against matched non-CF comparators in the general population and other inflammatory diseases. RESULTS: PwCF had a high prevalence of diabetes but low rates of hypertension and obesity. Some cardiac risk factors (age, diabetes and hypertension) were associated with MACE, but relationships between disease-specific risk factors (lung function and intravenous antibiotic days) were also observed. In propensity score-matched analyses, PwCF had higher risk of MACE than matched general population comparators (hazard ratio (HR) 1.65, 95% CI 1.40-1.95; p<0.001) and an equivalent or higher relative risk compared with other inflammatory conditions considered "high risk" for cardiovascular disease, including systemic lupus erythematosus (HR 0.95, 95% CI 0.82-1.09; p=0.44), rheumatoid arthritis (HR 1.21, 95% CI 1.00-1.48; p<0.001) and HIV (HR 0.93, 95% CI 0.82-1.06; p=0.29). CONCLUSIONS: PwCF are at increased risk of adverse cardiac disease events. Future work should focus on defining determinants of cardiovascular risk such that appropriate risk stratification can be employed.

Use of Dynamic Chest Radiography to Assess Treatment of Pulmonary Exacerbations in Cystic Fibrosis.

Background Although spirometry is an important marker in the management of pulmonary exacerbations in cystic fibrosis (CF), it is a forced maneuver and can generate aerosol. Therefore, it may be difficult to perform in some individuals. Dynamic chest radiography (DCR) provides real-time information regarding pulmonary dynamics alongside fluoroscopic-style thoracic imaging. Purpose To assess the effect of pulmonary exacerbation treatment by using both spirometry and DCR and assess the clinical utility of DCR in participants with CF experiencing pulmonary exacerbations. Materials and Methods In this prospective, observational, single-center pilot study, spirometry and DCR were performed before and after treatment of pulmonary exacerbations in participants with CF between December 2019 and August 2020. Spirometry measured forced expiratory volume in 1 second (FEV1) and forced vital capacity. DCR helped to measure projected lung area (PLA), hemidiaphragm midpoint position, and speed during tidal and deep breathing. Data were analyzed by using the paired t test or Wilcoxon signed-rank test. Correlation was assessed by using the Spearman rank correlation coefficient. Results Twenty participants with CF (mean age, 25 years ± 7 [standard deviation]; 14 women) were evaluated. Spirometry showed that percentage predicted FEV1 improved from a median of 44% (interquartile range [IQR], 17%) before treatment to 55% (IQR, 16%) after treatment (P = .004). DCR showed improvement in median deep breathing excursion for left and right hemidiaphragms (from 18 [IQR, 11] to 25 [IQR, 16] mm [P = .03] and from 13 [IQR, 6] to 19 [IQR, 14] mm [P = .03], respectively) and in median expiratory speed following deep breathing for left and right hemidiaphragms (from 7 [IQR, 2] to 11 [IQR, 5] mm/sec [P = .004] and 6 [IQR, 3] to 9 [IQR, 6] mm/sec [P = .004], respectively). PLA rate of change during full expiration and change in PLA during tidal breathing improved (from a mean of 42 cm2/sec ± 16 to 56 cm2/sec ± 24 [P = .03] and from a mean of 29 cm2 ± 14 to 35 cm2 ± 10 [P = .03], respectively). Conclusion Dynamic chest radiography demonstrated improvement in diaphragm speed and range of chest wall movement during respiration aftere treatment for pulmonary exacerbations in cystic fibrosis and showed potential as a tool to investigate the effect of pulmonary exacerbations on lung mechanics. Clinical trials registration no. NCT01234567 Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Physical activity assessment and vascular function in adults with cystic fibrosis and their non-CF peers.

An understanding of physical activity (PA) and related health benefits remains limited in adults with Cystic Fibrosis (CF). Raw acceleration data metrics may improve the quality of assessment and further this understanding. The study aimed to compare PA between people with CF (pwCF) and non-CF peers and examine associations between PA, vascular function and health outcome measures. PA was assessed in 62 participants (31 pwCF) using ActiGraph accelerometers. Vascular function (a marker of cardiovascular disease risk) was assessed using flow-mediated dilatation (FMD) in sub-groups of pwCF (n = 12) and matched controls. Average Euclidean norm minus one (ENMO) (total PA) was significantly lower (p = 0.005) in pwCF (35.09 ± 10.60 mg), than their non-CF peers (44.62 ± 13.78 mg). PwCF had PA profiles (intensity gradient) indicative of more time in lower intensity activity (-2.62 ± 0.20, -2.37 ± 0.23). Vigorous activity was positively associated with lung function (rs = 0.359) and Quality of Life (r = 0.412). There were no significant differences (p = 0.313) in FMD% between pwCF (5.29 ± 2.76%) and non-CF peers (4.34 ± 1.58%) and no associations with PA. PwCF engaged in less moderate-to-vigorous PA and demonstrated a steeper PA profile than their non-CF peers.

Cystic fibrosis: Diagnosis and management - NICE guideline 78.

NICE produced a guideline for the diagnosis and management of CF (NG78) in October 2017. This paper describes the process of producing the guideline and highlights some of the areas covered by it, including ideas for further research and tools that can be used by purchasers to help improve CF care.

Evaluation of Gastric Emptying in Cystic Fibrosis Using Bedside Ultrasonography.

OBJECTIVES: Although gastric emptying rate (GER) influences incretin response and nutrient absorption, both defective in people with cystic fibrosis (CF), there are few studies in this group, and the circadian rhythm is unknown. We employed an ultrasonographic technique to assess GER in people with CF following liquid and mixed meals and also evaluated the circadian rhythm, compared to normal controls. METHODS: Thirteen pancreatic-insufficient adults with CF and 10 healthy controls underwent a fasting oral glucose tolerance test (OGTT; liquid meal) and on a second visit underwent a fasting mixed meal test (MMT) thrice on the same day. GER was measured during the OGTT and each MMT using a 3.5-MHz abdominal transducer probe at baseline and 30, 60, 90, and 120 minutes. RESULTS: Controls had normal GER for both OGTT and MMT. Compared to controls, people with CF had delayed GER60 for OGTT (mean 46%), which increased with time (P = .001), and also delayed GER90 for MMT in the morning (mean 56%), afternoon (58%), and evening (59%). The GER in the control group was better at all time points throughout the day compared to patients with CF. CONCLUSIONS: This is the first study to use ultrasonography, an inexpensive bedside technique, to assess GER in adults with CF. For the first time, we have shown that adults with CF have delayed GER for both liquid and mixed meals, and this delay continues throughout the day.

Pseudomonas aeruginosa adaptation and diversification in the non-cystic fibrosis bronchiectasis lung.

To characterise Pseudomonas aeruginosa populations during chronic lung infections of non-cystic fibrosis bronchiectasis patients, we used whole-genome sequencing to 1) assess the diversity of P. aeruginosa and the prevalence of multilineage infections; 2) seek evidence for cross-infection or common source acquisition; and 3) characterise P. aeruginosa adaptations.189 isolates, obtained from the sputa of 91 patients attending 16 adult bronchiectasis centres in the UK, were whole-genome sequenced.Bronchiectasis isolates were representative of the wider P. aeruginosa population. Of 24 patients from whom multiple isolates were examined, there were seven examples of multilineage infections, probably arising from multiple infection events. The number of nucleotide variants between genomes of isolates from different patients was in some cases similar to the variations observed between isolates from individual patients, implying the possible occurrence of cross-infection or common source acquisition.Our data indicate that during infections of bronchiectasis patients, P. aeruginosa populations adapt by accumulating loss-of-function mutations, leading to changes in phenotypes including different modes of iron acquisition and variations in biofilm-associated polysaccharides. The within-population diversification suggests that larger scale longitudinal surveillance studies will be required to capture cross-infection or common source acquisition events at an early stage.

Divergent, coexisting Pseudomonas aeruginosa lineages in chronic cystic fibrosis lung infections.

RATIONALE: Pseudomonas aeruginosa, the predominant cause of chronic airway infections of patients with cystic fibrosis, exhibits extensive phenotypic diversity among isolates within and between sputum samples, but little is known about the underlying genetic diversity. OBJECTIVES: To characterize the population genetic structure of transmissible P. aeruginosa Liverpool Epidemic Strain in chronic infections of nine patients with cystic fibrosis, and infer evolutionary processes associated with adaptation to the cystic fibrosis lung. METHODS: We performed whole-genome sequencing of P. aeruginosa isolates and pooled populations and used comparative analyses of genome sequences including phylogenetic reconstructions and resolution of population structure from genome-wide allele frequencies. MEASUREMENTS AND MAIN RESULTS: Genome sequences were obtained for 360 isolates from nine patients. Phylogenetic reconstruction of the ancestry of 40 individually sequenced isolates from one patient sputum sample revealed the coexistence of two genetically diverged, recombining lineages exchanging potentially adaptive mutations. Analysis of population samples for eight additional patients indicated coexisting lineages in six cases. Reconstruction of the ancestry of individually sequenced isolates from all patients indicated smaller genetic distances between than within patients in most cases. CONCLUSIONS: Our population-level analysis demonstrates that coexistence of distinct lineages of P. aeruginosa Liverpool Epidemic Strain within individuals is common. In several cases, coexisting lineages may have been present in the infecting inoculum or assembled through multiple transmissions. Divergent lineages can share mutations via homologous recombination, potentially aiding adaptation to the airway during chronic infection. The genetic diversity of this transmissible strain within infections, revealed by high-resolution genomics, has implications for patient segregation and therapeutic strategies.

Potential impact on fertility of new systemic therapies for cystic fibrosis.

Cystic fibrosis is primarily considered a respiratory disease with superadded pancreatic dysfunction; however the underlying genetic mutation results in the abnormal function of cells throughout the body - including tissues involved in reproduction. Practically all males and up to 50% of females with CF will suffer fertility issues - the causes of which are multifactorial and could be improved by treatments that target the underlying physiological deficit, such as ivacaftor. We consider the mechanisms by which the rapidly developing field of systemic treatments for CF could impact on the fertility of this group and review the available real world evidence.

Informed conditioning on clinical covariates increases power in case-control association studies.

Genetic case-control association studies often include data on clinical covariates, such as body mass index (BMI), smoking status, or age, that may modify the underlying genetic risk of case or control samples. For example, in type 2 diabetes, odds ratios for established variants estimated from low-BMI cases are larger than those estimated from high-BMI cases. An unanswered question is how to use this information to maximize statistical power in case-control studies that ascertain individuals on the basis of phenotype (case-control ascertainment) or phenotype and clinical covariates (case-control-covariate ascertainment). While current approaches improve power in studies with random ascertainment, they often lose power under case-control ascertainment and fail to capture available power increases under case-control-covariate ascertainment. We show that an informed conditioning approach, based on the liability threshold model with parameters informed by external epidemiological information, fully accounts for disease prevalence and non-random ascertainment of phenotype as well as covariates and provides a substantial increase in power while maintaining a properly controlled false-positive rate. Our method outperforms standard case-control association tests with or without covariates, tests of gene x covariate interaction, and previously proposed tests for dealing with covariates in ascertained data, with especially large improvements in the case of case-control-covariate ascertainment. We investigate empirical case-control studies of type 2 diabetes, prostate cancer, lung cancer, breast cancer, rheumatoid arthritis, age-related macular degeneration, and end-stage kidney disease over a total of 89,726 samples. In these datasets, informed conditioning outperforms logistic regression for 115 of the 157 known associated variants investigated (P-value = 1 × 10(-9)). The improvement varied across diseases with a 16% median increase in χ(2) test statistics and a commensurate increase in power. This suggests that applying our method to existing and future association studies of these diseases may identify novel disease loci.

Highlights of the North American CF Conference 2013.

This is a personal selection of papers that were presented at the 27th North American Cystic Fibrosis Conference held in Salt Lake City in October 2013. The papers discussed in this review are thought to be of particular interest to CF caregivers in the UK.

Coming of age in cystic fibrosis - transition from paediatric to adult care.

Cystic fibrosis (CF) is the most common multi-system inherited disorder, with a UK population exceeding 9,000. There have been significant improvements in CF survival over the decades, attributed to improvements in therapies available, our understanding of the disease and better organisation of care. CF care providers have been early advocates for successful healthcare transition from the paediatric to adult sector and CF can be considered a model process where a paediatric disease has now become an adult one. This article looks at the transition process in CF and the future challenges CF physicians will face.

Dynamic chest radiography: a state-of-the-art review.

Dynamic chest radiography (DCR) is a real-time sequential high-resolution digital X-ray imaging system of the thorax in motion over the respiratory cycle, utilising pulsed image exposure and a larger field of view than fluoroscopy coupled with a low radiation dose, where post-acquisition image processing by computer algorithm automatically characterises the motion of thoracic structures. We conducted a systematic review of the literature and found 29 relevant publications describing its use in humans including the assessment of diaphragm and chest wall motion, measurement of pulmonary ventilation and perfusion, and the assessment of airway narrowing. Work is ongoing in several other areas including assessment of diaphragmatic paralysis. We assess the findings, methodology and limitations of DCR, and we discuss the current and future roles of this promising medical imaging technology.Critical relevance statement Dynamic chest radiography provides a wealth of clinical information, but further research is required to identify its clinical niche.

Feasibility of dynamic chest radiography to calculate lung volumes in adult people with cystic fibrosis: a pilot study.

INTRODUCTION: Dynamic chest radiography (DCR) is a novel, low-dose, real-time digital imaging system where software identifies moving thoracic structures and can automatically calculate lung areas. In an observational, prospective, non-controlled, single-centre pilot study, we compared it with whole-body plethysmography (WBP) in the measurement of lung volume subdivisions in people with cystic fibrosis (pwCF). METHODS: Lung volume subdivisions were estimated by DCR using projected lung area (PLA) during deep inspiration, tidal breathing and full expiration, and compared with same-day WBP in 20 adult pwCF attending routine review. Linear regression models to predict lung volumes from PLA were developed. RESULTS: Total lung area (PLA at maximum inspiration) correlated with total lung capacity (TLC) (r=0.78, p<0.001), functional residual lung area with functional residual capacity (FRC) (r=0.91, p<0.001), residual lung area with residual volume (RV) (r=0.82, p=0.001) and inspiratory lung area with inspiratory capacity (r=0.72, p=0.001). Despite the small sample size, accurate models were developed for predicting TLC, RV and FRC. CONCLUSION: DCR is a promising new technology that can be used to estimate lung volume subdivisions. Plausible correlations between plethysmographic lung volumes and DCR lung areas were identified. Further studies are needed to build on this exploratory work in both pwCF and individuals without CF. TRIAL REGISTRATION NUMBER: ISRCTN64994816.

Are early life factors considered when managing respiratory disease? A British Thoracic Society survey of current practice.

BACKGROUND: We hypothesised that early life events are not routinely considered by most respiratory specialists. METHODS: Respiratory Specialists were surveyed via the British Thoracic Society (BTS) on whether they asked patients about birth weight, preterm birth and prenatal and postnatal complications. RESULTS: Only a small minority (mostly hospital paediatricians) of the 123 who replied asked most respiratory patients about one of more early life factors. Patient recall of the information when asked was low. CONCLUSIONS: The survey results suggest little current consideration is given to early life factors in adult respiratory medicine, despite increasing evidence that early life factors do impact on later respiratory health. Improving training, increasing awareness and exploring new approaches to obtaining the information are required.

Transmissible strains of Pseudomonas aeruginosa in cystic fibrosis lung infections.

Pseudomonas aeruginosa chronic lung infections are the major cause of morbidity and mortality associated with cystic fibrosis. For many years, the consensus was that cystic fibrosis patients acquire P. aeruginosa from the environment, and hence harbour their own individual clones. However, in the past 15 yrs the emergence of transmissible strains, in some cases associated with greater morbidity and increased antimicrobial resistance, has changed the way that many clinics treat their patients. Here we provide a summary of reported transmissible strains in the UK, other parts of Europe, Australia and North America. In particular, we discuss the prevalence, epidemiology, unusual genotypic and phenotypic features, and virulence of the most intensively studied transmissible strain, the Liverpool epidemic strain. We also discuss the clinical impact of transmissible strains, in particular the diagnostic and infection control approaches adopted to counter their spread. Genomic analysis carried out so far has provided little evidence that transmissibility is due to shared genetic characteristics between different strains. Previous experiences with transmissible strains should help us to learn lessons for the future. In particular, there is a clear need for strain surveillance if emerging problem strains are to be detected before they are widely transmitted.

Pseudomonas aeruginosa population diversity and turnover in cystic fibrosis chronic infections.

RATIONALE: Pseudomonas aeruginosa isolates from chronic cystic fibrosis lung infections display multiple phenotypes indicating extensive population diversity. OBJECTIVES: We aimed to examine how such diversity is distributed within and between patients, and to study the dynamics of single-strain phenotypic diversity in multiple patients through time. METHODS: Sets of 40 P. aeruginosa isolates per sputum samples were analyzed for a series of phenotypic and genotypic characteristics. Population differentiation between patients, between samples within patients, and between isolates within samples was analyzed. MEASUREMENTS AND MAIN RESULTS: We characterized 15 traits for a total of 1,720 isolates of an important and widely disseminated epidemic strain of P. aeruginosa from 10 chronically infected patients with cystic fibrosis multiply sampled during 2009. Overall, 43 sputum samples were analyzed and 398 haplotypes of the Liverpool Epidemic Strain were identified. The majority of phenotypic diversity occurred within patients. Such diversity is highly dynamic, displaying rapid turnover of haplotypes through time. P. aeruginosa populations within each individual sputum sample harbored extensive diversity. Although we observed major changes in the haplotype composition within patients between samples taken at intervals of several months, the compositions varied much less during exacerbation periods, despite the use of intravenous antibiotics. Our data also highlight a correlation between periods of pulmonary exacerbation and the overproduction of pyocyanin, a quorum sensing-controlled virulence factor. CONCLUSIONS: These results significantly advance our understanding of the within-host population biology of P. aeruginosa during infection of patients with cystic fibrosis, and provide in vivo evidence for a link between pyocyanin production and patient morbidity.

Eruptive melanocytic naevi following initiation of elexacaftor/ivacaftor/tezacaftor for cystic fibrosis.

A 29 year old woman with cystic fibrosis (CF) presented to CF clinic following the sudden development of over 200 pigmented naevi located predominately on the trunk and limbs 3 months after commencing elexacaftor/tezacaftor/ivacaftor, a novel triple-therapy CFTR modulator therapy for CF. Skin biopsy confirmed benign naevi and the clinical presentation was consistent with eruptive melanocytic naevi. Elexacaftor/tezacaftor/ivacaftor received marketing authorisation in August 2020 and this is the first report of associated naevi. The individual described here remains clinically well, and continues on elexacaftor/tezacaftor/ivacaftor with dermatology follow-up.

Characterisation of hemidiaphragm dysfunction using dynamic chest radiography: a pilot study.

OBJECTIVES: Dynamic chest radiography (DCR) is a novel real-time digital fluoroscopic imaging system that produces clear, wide field-of-view diagnostic images of the thorax and diaphragm in motion, alongside novel metrics on moving structures within the thoracic cavity. We describe the use of DCR in the measurement of diaphragm motion in a pilot series of cases of suspected diaphragm dysfunction. METHODS: We studied 21 patients referred for assessment of diaphragm function due to suspicious clinical symptoms or imaging (breathlessness, orthopnoea, reduced exercise tolerance and/or an elevated hemidiaphragm on plain chest radiograph). All underwent DCR with voluntary sniff manoeuvres. RESULTS: Paradoxical motion on sniffing was observed in 14 patients, and confirmed in six who also underwent fluoroscopy or ultrasound. In four patients, DCR showed reduced hemidiaphragm excursion, but no paradoxical motion; in three, normal bilateral diaphragm motion was demonstrated. DCR was quick to perform, and well tolerated in all cases and with no adverse events reported. DCR was achieved in ∼5 min per patient, with images available to view by the clinician immediately within the clinical setting. CONCLUSION: DCR is a rapid, well-tolerated and straightforward chest radiography technique that warrants further investigation in the assessment of diaphragm dysfunction.