Year-to-year changes in lung function in individuals with cystic fibrosis

The solute carrier family 26 member 9 modifies rapidly progressing cystic fibrosis associated with homozygous F508del CFTR mutation

BACKGROUND AND AIMS

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations to the CF transmembrane conductance regulator (CFTR). Symptoms and severity of the disease can be quite variable suggesting modifier genes play an important role.

MATERIALS AND METHODS

Exome sequencing was performed on six individuals carrying homozygous deltaF508 for CFTR genotype but present with rapidly progressing CF (RPCF). Data was analyzed using an unbiased genome-wide genetic burden test against 3076 controls. Single cell RNA sequencing data from LungMAP was utilized to evaluate unique and co-expression of candidate genes, and structural modeling to evaluate the deleterious effects of identified candidate variants.

RESULTS

We have identified solute carrier family 26 member 9 (SLC26A9) as a modifier gene to be associated with RPCF. Two rare missense SLC26A9 variants were discovered in three of six individuals deemed to have RPCF: c.229G > A; p.G77S (present in two patients), and c.1885C > T; p.P629S. Co-expression of SLC26A9 and CFTR mRNA is limited across different lung cell types, with the highest level of co-expression seen in human (6.3 %) and mouse (9.0 %) alveolar type 2 (AT2) cells. Structural modeling suggests deleterious effects of these mutations as they are in critical protein domains which might affect the anion transport capability of SLC26A9.

CONCLUSION

The enrichment of rare and potentially deleterious SLC26A9 mutations in patients with RPCF suggests SLC26A9 may act as an alternative anion transporter in CF and is a modifier gene associated with this lung phenotype.

Factors associated with pulmonary function decline of patients in the cystic fibrosis registry of Turkey: A retrospective cohort study

BACKGROUND

The decline in pulmonary function is a predictor of disease progression in patients with cystic fibrosis (CF). This study aimed to determine the decline rate of percent predicted forced expiratory volume in 1 s (ppFEV1) based on the data of the CF Registry of Turkey. The secondary aim was to investigate the risk factors related to the decline in ppFEV1.

METHODS

A retrospective cohort study of CF patients over 6 years old, with pulmonary function data over at least 2 years of follow-up was extracted from the national CF registry for years 2017-2019. Patients were classified according to disease severity and age groups. Multivariate analysis was used to predict the decline in ppFEV1 and to investigate the associated risk factors.

RESULTS

A total of 1722 pulmonary function test results were available from 574 patients over the study period. Mean diagnostic age was older and weight for age, height for age, and body mass index z scores were significantly lower in the group of ppFEV1 < 40, while chronic Pseudomonas aeruginosa (p < .001) and mucoid P. aeruginosa colonization (p < .001) were significantly higher in this group (p < .001). Overall mean annual ppFEV1 decline was -0.97% (95% confidence interval [CI] = -0.02 to -1.92%). The mean change of ppFEV1 was significantly higher in the group with ppFEV1 ≥ 70 compared with the other (ppFEV1 < 40 and ppFEV1: 40-69) two groups (p = .004). Chronic P. aeruginosa colonization (odds ratio [OR] = 1.79 95% CI = 1.26-2.54; p = .01) and initial ppFEV1 ≥ 70 (OR = 2.98 95% CI = 1.06-8.36), p = .038) were associated with significant ppFEV1 decline in the whole cohort.

CONCLUSIONS

This data analysis recommends close follow-up of patients with normal initial ppFEV1 levels at baseline; advocates for early interventions for P. aeruginosa; and underlines the importance of nutritional interventions to slow down lung disease progression.

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.

Predictors of Transition Outcomes in Cystic Fibrosis: Analysis of National Patient Registry and CF RISE (Responsibility. Independence. Self-care. Education) Data

OBJECTIVE

To identify predictors of change in lung function and body weight during health care transition in cystic fibrosis (CF).

METHODS

We conducted a retrospective cohort study using data from the CF Foundation Patient Registry and the web-based transition program CF RISE (Responsibility. Independence. Self-care. Education) for patients aged 16-25 years who transitioned to adult care from 2013 through 2019. We modeled change in forced expiratory volume in 1 second % predicted and weight using linear regression fit with generalized estimating equations. Predictors included gap in care (time between last pediatric and first adult outpatient visit), transition program engagement, and sociodemographic and medical factors.

RESULTS

Among 12 420 adolescents and young adults (AYAs), 3876 transitioned to adult care with a median gap in care of 7.6 months. Patients from CF centers with greater rates of CF RISE engagement had improved lung function and weight at their first adult outpatient visit. Coverage on a parent's insurance plan and absence of CF complications predicted increased lung function. History of a nonlung transplant and sinus disease predicted increased weight. Comorbid diabetes mellitus and gaps in care >3 months predicted decreased lung function with longer gaps in care associated with greater decrease. A gap in care of 6-9 months predicted decreased weight. Control variables including baseline forced expiratory volume in 1 second and weight, and exacerbation status were also statistically significant.

CONCLUSIONS

Findings suggest 2 promising targets to improve transition of AYAs with CF: increasing AYA engagement in CF RISE and reducing gaps in care during the transition period.

Respiratory system parameters in children with low severity cystic fibrosis: is there early involvement in relation to healthy peers?

OBJECTIVE

To compare and analyze pulmonary function and respiratory mechanics parameters between healthy children and children with cystic fibrosis.

METHODS

This cross-sectional analytical study included healthy children (HSG) and children with cystic fibrosis (CFG), aged 6-13 years, from teaching institutions and a reference center for cystic fibrosis in Florianópolis/SC, Brazil. The patients were paired by age and sex. Initially, an anthropometric evaluation was undertaken to pair the sample characteristics in both groups; the medical records of CFG were consulted for bacterial colonization, genotype, and disease severity (Schwachman-Doershuk Score - SDS) data. Spirometry and impulse oscillometry were used to assess pulmonary function.

RESULTS

In total, 110 children were included, 55 in each group. In the CFG group, 58.2% were classified as excellent by SDS, 49.1% showed the ΔF508 heterozygotic genotype, and 67.3% were colonized by some pathogens. Statistical analysis revealed significant differences between both groups (p<0.05) in most pulmonary function parameters and respiratory mechanics.

CONCLUSIONS

Children with cystic fibrosis showed obstructive ventilatory disorders and compromised peripheral airways compared with healthy children. These findings reinforce the early changes in pulmonary function and mechanics associated with this disease.

Gaps in Cystic Fibrosis Care Are Associated with Reduced Lung Function in the U.S. Cystic Fibrosis Foundation Patient Registry

Rationale: Cystic fibrosis (CF) is a genetic disease leading to progressive lung function loss and early mortality. Many clinical and demographic variables are associated with lung function decline, but little is known about the effects of prolonged periods of missed care. Objectives: To determine if missed care in the Cystic Fibrosis Foundation Patient Registry (CFFPR) is associated with decreased lung function at follow-up visits. Methods: Deidentified CFFPR data for 2004-2016 were analyzed, with the exposure of interest being ⩾12-month gap in CFFPR data. We modeled percentage predicted forced expiratory volume in 1 second using longitudinal semiparametric modeling with natural cubic splines for age (knots at quantiles) and with subject-specific random effects, adjusted for sex and CFTR (cystic fibrosis transmembrane conductance regulator) genotype, race, and ethnicity and included time-varying covariates for gaps in care, insurance type, underweight body mass index, CF-related diabetes status, and chronic infections. Results: A total of 24,328 individuals with 1,082,899 encounters in the CFFPR met inclusion criteria. In the cohort, 8,413 (35%) individuals had at least a single ⩾12-month episode of discontinuity, whereas 15,915 (65%) had continuous care. Of the encounters preceded by a 12-month gap, 75.8% occurred in patients 18 years and older. Compared with those with continuous care, those with a discontinuous care episode had a lower follow-up percentage predicted forced expiratory volume in 1 second at the index visit (-0.81%; 95% confidence interval, -1.00, -0.61) after adjustment for other variables. The magnitude of this difference was much greater (-2.1%; 95% confidence interval, -1.5, -2.7) in young adult F508del homozygotes. Conclusions: There was a high rate of ⩾12-month gap in care, especially in adults, documented in the CFFPR. Discontinuous care identified in the CFFPR was strongly associated with decreased lung function, especially in adolescents and young adults homozygous for the F508del CFTR mutation. This may have implications for identifying and treating people with lengthy gaps in care and may have implications for CFF care recommendations.

Lung Function Decline in Cystic Fibrosis: Impact of Data Availability and Modeling Strategies on Clinical Interpretations

Rationale: Studies estimating the rate of lung function decline in cystic fibrosis have been inconsistent regarding the methods used. How the methodology used impacts the validity of the results and comparability between studies is unknown. Objectives: The Cystic Fibrosis Foundation established a work group whose tasks were to examine the impact of differing approaches to estimating the rate of decline in lung function and to provide analysis guidelines. Methods: We used a natural history cohort of 35,252 individuals with cystic fibrosis aged ⩾6 years in the Cystic Fibrosis Foundation Patient Registry (CFFPR), 2003-2016. Modeling strategies using linear and nonlinear forms of marginal and mixed-effects models, which have previously quantified the rate of forced expiratory volume in 1 second (FEV1) decline (percent predicted per year), were evaluated under clinically relevant scenarios of available lung function data. Scenarios varied by sample size (overall CFFPR, medium-sized cohort of 3,000 subjects, and small-sized cohort of 150), data collection/reporting frequency (encounter, quarterly, and annual), inclusion of FEV1 during pulmonary exacerbation, and follow-up length (<2 yr, 2-5 yr, entire duration). Results: Rate of FEV1 decline estimates (percent predicted per year) differed between linear marginal and mixed-effects models; overall cohort estimates (95% confidence interval) were 1.26 (1.24-1.29) and 1.40 (1.38-1.42), respectively. Marginal models consistently estimated less rapid lung function decline than mixed-effects models across scenarios, except for short-term follow-up (both were ∼1.4). Rate of decline estimates from nonlinear models diverged by age 30. Among mixed-effects models, nonlinear and stochastic terms fit best, except for short-term follow-up (<2 yr). Overall CFFPR analysis from a joint longitudinal-survival model implied that an increase in rate of decline of 1% predicted per year in FEV1 was associated with a 1.52-fold (52%) increase in the hazard of death/lung transplant, but the results exhibited immortal cohort bias. Conclusions: Differences were as high as 0.5% predicted per year between rate of decline estimates, but we found estimates were robust to lung function data availability scenarios, except short-term follow-up and older age ranges. Inconsistencies among previous study results may be attributable to inherent differences in study design, inclusion criteria, or covariate adjustment. Results-based decision points reported herein will support researchers in selecting a strategy to model lung function decline most reflective of nuanced, study-specific goals.

Tezacaftor-ivacaftor use in routine care of adults with cystic fibrosis: a medicine use evaluation

OBJECTIVES

Cystic fibrosis is a devastating life-limiting genetic condition characterised by a progressive decline in lung function, respiratory infections and premature death. Tezacaftor-ivacaftor is a combined cystic fibrosis transmembrane conductance regulator (CFTR) modulator that targets the underlying cause of the disease. This study aimed to assess the impact of tezacaftor-ivacaftor use in routine clinical practice for adults with cystic fibrosis.

METHODS

A retrospective observational longitudinal cohort study design was applied to examine the clinical effect of tezacaftor-ivacaftor in routine practice in the West of Scotland Adult Cystic Fibrosis Unit. Adults receiving tezacaftor-ivacaftor for at least 4 weeks were included in this medicine use evaluation.A standardised data form was used to collect patient-level data: demographics, genotype, complications of cystic fibrosis, medicine access process. Fifty-two weeks pre and post tezacaftor-ivacaftor initiation data: lung function, body mass index (BMI), days spent in hospital, days receiving antibiotic treatment for respiratory exacerbations. Anonymised data were collated and analysed using SPSS V.26.

RESULTS

Of 121 potential patients, 45 received treatment with tezacaftor-ivacaftor; median age 30 years (range 17-64) at initiation, 56% were male, 76% were deemed to be homozygote and 41 patients continued treatment for at least 52 weeks. There was no significant change in % predicted FEV1; median difference 0 (IQR -3 to 6). There was a significant improvement in BMI, mean 0.6 kg/m2 (95% CI 0.2 to 1.0), as well as a median 4 (IQR -17 to 0) day reduction in days in hospital and 21 (IQR -42 to 0) day reduction in days receiving antibiotics.

CONCLUSIONS

The use of tezacaftor-ivacaftor in routine practice for people with cystic fibrosis was associated with improvements in weight, as well as reducing the number of days people needed to spend in hospital and receive antibiotics.

EFFECT OF ELEXACAFTOR/TEZACAFTOR/IVACAFTOR ON ANNUAL RATE OF LUNG FUNCTION DECLINE IN PEOPLE WITH CYSTIC FIBROSIS

Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was shown to be safe and efficacious in people with cystic fibrosis (CF) with ≥ 1 F508del-CFTR allele in Phase 3 clinical trials. ELX/TEZ/IVA treatment led to improved lung function, with increases in percent predicted forced expiratory volume in 1 second (ppFEV1) and Cystic Fibrosis Questionnaire-Revised respiratory domain score. Here, we evaluated the impact of ELX/TEZ/IVA on the rate of lung function decline over time by comparing changes in ppFEV1 in participants from the Phase 3 trials with a matched group of people with CF from the US Cystic Fibrosis Foundation Patient Registry not eligible for cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy. Participants treated with ELX/TEZ/IVA had on average no loss of pulmonary function over a 2-year period (mean annualized rate of change in ppFEV1, +0.39 percentage points [95% CI, -0.06 to 0.85]) compared with a 1.92 percentage point annual decline (95% CI, -2.16 to -1.69) in ppFEV1 in untreated controls. ELX/TEZ/IVA is the first CFTR modulator therapy shown to halt lung function decline over an extended time period.

Adherence, reliability, and variability of home spirometry telemonitoring in cystic fibrosis

Introduction

Forced spirometry is the gold standard to assess lung function, but its accessibility may be limited. By contrast, home spirometry telemonitoring allows a multi-weekly lung function follow-up but its real-life adherence, reliability, and variability according to age have been poorly studied in patients with CF (PwCF). We aimed to compare real-life adherence, reliability and variability of home spirometry between children, teenagers and adults with CF.

Methods

This real-life observational study included PwCF followed for six months in whom lung function (i.e, forced expiratory volume maximum in 1 s (FEV1), forced vital capacity (FVC), forced mid-expiratory flow (FEF) and FEV1/FVC ratio) was monitored by both conventional and home spirometry between July 2015 and December 2021. The adherence, reliability and variability of home spirometry was assessed in all PwCF and compared between children (<12years old), teenagers (12-18 years old) and adults.

Results

174 PwCF were included (74 children, 43 teenagers and 57 adults). Home spirometry was used at least one time per week by 64.1 ± 4.9% PwCF, more frequently in children and teenagers than in adults (79.4 ± 2.9%, 69.2 ± 5.5% and 40.4 ± 11.5% respectively). The reliability to conventional lung function testing was good for all assessed parameters (e.g., FEV1: r = 0.91, p < 0.01) and the variability over the 6 months of observation was low (FEV1 coefficient of variation = 11.5%). For each parameter, reliability was better, and the variability was lower in adults than in teenagers than in children.

Conclusion

Home spirometry telemonitoring appears to be a reliable tool for multi-weekly lung function follow-up of PwCF.

Six-minute walk test and factors affecting exercise capacity in children with cystic fibrosis

PURPOSE

This study aimed to compare the result of the six-minute walk test (6MWT) in patients with cystic fibrosis (CF) aged < 20 years old and individuals without CF.

METHODS

In this cross-sectional study, 50 children and adolescents with CF and 20 children and adolescents without CF underwent the 6MWT. Vital signs before and immediately after the 6MWT and six-minute walk distance (6MWD) were evaluated.

RESULTS

The mean change in heart rate, percentage of peripheral oxygen saturation (SpO2%), systolic blood pressure, respiratory rate, and dyspnea severity during the 6MWT was significantly higher in patients with CF. In the case group, 6MWD was associated with regular chest physical therapy (CPT) and forced expiratory volume (FEV)> 80%. Patients with CF receiving regular CPT or mechanical vibration and with FEV in the first second > 80% showed better physical capacity during the 6MWT (smaller Sp02% decline and lower dyspnea perception).

CONCLUSION

Children and adolescents with CF have lower physical capacity compared to individuals without CF. CPT and mechanical vibration could be used to increase physical capacity in this population.

Pulmonary exacerbations, airway pathogens, and long-term course of lung clearance index in children and young adults with cystic fibrosis

BACKGROUND

Pulmonary exacerbations (PEx), pathogens colonizing the respiratory tract, and patients' age are associated with progressive worsening of lung function among patients with cystic fibrosis (CF). However, the effect of these factors on longitudinal changes of Lung Clearance Index (LCI) remains unclear.

AIM

To assess the role of age, different types of bronchial infection, and PEx on LCI deterioration.

METHODS

We conducted a retrospective study assessing multiple-breath washout (MBW) and spirometry changes among CF patients evaluated at quarterly outpatient clinic visits over 8 years. MBW and spirometry were performed at each visit, sputum samples and/or cough swabs were obtained for culture, whereas respiratory symptoms and clinical examination findings were recorded. Patients who had ≥5 serial MBW measurements, one of which coincided with a pulmonary exacerbation, were reviewed.

RESULTS

Seventy-six patients were included in the study: mean age of 10.61 years (range 1.75-23.75). A total of 1152 MBW tests and 1047 spirometry tests were performed. LCI was significantly higher among CF patients aged 11-15, 16-20, and over 20 years than those under 5 years of age; ΔLCI: 1.16 (confidence interval [CI] 0.43-1.90) and 3.25 (CI 2.33-4.17), respectively. Furthermore, LCI was significantly elevated in CF patients with positive cultures for Pseudomonas aeruginosa (0.52 LCI [CI -0.12 to 0.71]) and Stenotrophomonas Maltophilia (1.41 LCI [CI 0.61-2.21]). Moreover, increased values of LCI in CF patients were significantly associated with increased risk of PEx (odds ratio [OR] 1.19, CI [1.14-1.25], p < 0.001).

CONCLUSION

LCI demonstrates a progression of lung disease and corresponds to changes in bacterial infections and PEx among patients with CF. LCI may be a valuable marker for tracking disease deterioration and may have a role in the routine clinical care of patients with CF.

A Compositional Analysis of Physical Activity, Sedentary Time, and Sleep and Associated Health Outcomes in Children and Adults with Cystic Fibrosis

This study sought to investigate the association of light physical activity (LPA), moderate-to-vigorous physical activity (MVPA), sedentary time (SED), and sleep with lung function in children and adults with CF. In total, 86 children (41 females; 13.6 ± 2.8 years; FEV₁%_predicted: 86 ± 1%) and 43 adults (21 females; 24.6 ± 4.7 years; FEV₁%_predicted: 63 ± 21%) with CF participated in this study. Wrist-worn accelerometery was used to assess PA, SED and sleep. Compositional linear regression models were conducted following normalisation via isometric log-ratio transformations. Sequential binary partitioning was applied to investigate the impact of reallocating 10 to 30 min between each behaviour on FEV₁%_predicted. A decline in FEV₁%_predicted was predicted with the reallocation of 30 min from MVPA to SED or LPA or sleep to any other behaviour in children (−3.04–−0.005%) and adults (−3.58–−0.005%). Conversely, improvements in FEV₁%_predicted were predicted when 30 min was reallocated to MVPA from LPA or SED in children (0.12–1.59%) and adults (0.77–2.10%), or when 30 min was reallocated to sleep from any other behaviour in both children (0.23–2.56%) and adults (1.08–3.58%). This study supports the importance of MVPA and sleep for maintaining and promoting lung function in people with CF.

An empirical comparison of segmented and stochastic linear mixed effects models to estimate rapid disease progression in longitudinal biomarker studies

Longitudinal studies of rapid disease progression often rely on noisy biomarkers; the underlying longitudinal process naturally varies between subjects and within an individual subject over time; the process can have substantial memory in the form of within-subject correlation. Cystic fibrosis lung disease progression is measured by changes in a lung function marker (FEV1), such as a prolonged drop in lung function, clinically termed rapid decline. Choosing a longitudinal model that estimates rapid decline can be challenging, requiring covariate specifications to assess drug effect while balancing choices of covariance functions. Two classes of longitudinal models have recently been proposed: segmented and stochastic linear mixed effects (LMEs) models. With segmented LMEs, random changepoints are used to estimate the timing and degree of rapid decline, treating these points as structural breaks in the underlying longitudinal process. In contrast, stochastic LMEs, such as random walks, are locally linear but utilize continuously changing slopes, viewing bouts of rapid decline as localized, sharp changes. We compare commonly utilized variants of these approaches through an application using the Cystic Fibrosis Foundation Patient Registry. Changepoint modeling had the worst fit and predictive accuracy but certain covariance forms in stochastic LMEs produced problematic variance estimates.

Lung Clearance Index in Children with Cystic Fibrosis during Pulmonary Exacerbation

(1) Background: Pulmonary exacerbation (PEx) is one of the main factors affecting the quality of life and life expectancy in patients with cystic fibrosis (CF). Our study aimed to evaluate the change in selected pulmonary function parameters, including lung clearance index (LCI), in patients with CF diagnosed with PEx. (2) Methods: We enrolled 40 children with CF aged 6–17. They performed spirometry and multiple breath nitrogen washout (MBNW) tests during a stable condition period at the beginning and the end of intravenous antibiotic treatment. (3) Results: LCI increased by 65% and FEV₁ decreased by ≥10% in 40% of patients with CF during PEx. An absolute change in LCI between a stable condition period and PEx was 1.05 (±1.92) units, which corresponds to a relative change of 11.48% (±18.61) of the baseline. The relative decrease in FEV₁ was −9.22% (±12.00) and the z-score was −0.67 (±1.13). After the PEx treatment, FEV₁ increased by 11.05% (±9.04) on average, whereas LCI decreased by 1.21 ± 1.59 units on average, which represented 9.42% ± 11.40 compared to the value at the beginning of PEx. (4) Conclusions: The change in LCI captures a higher proportion of events with functional impairment than FEV₁ in school-age children with CF.

Healthcare resource utilization and costs among children with cystic fibrosis in the United States

BACKGROUND

Adverse health impacts of cystic fibrosis (CF) can be present in children before respiratory complications are observed. Children with CF show progressive health decline, with increasing lung function decline in adolescence. This study aims to quantify the healthcare resource utilization (HCRU) and costs attributable to CF by comparing children with CF with the general pediatric population.

METHODS

This retrospective, cross-sectional, observational study compared HCRU and costs among children with CF in the US with demographically similar children without CF (comparison group) over a 12-month period using administrative claims data spanning 2010-2017. Analyses were conducted by insurance type (commercially insured [COM] and Medicaid insured [MED]) and stratified by age (<2 years, 2 to <6 years, 6 to <12 years, and 12-17 years).

RESULTS

Children with CF (2831 COM and 1896 MED) were matched to children in the comparison group (8493 COM and 5688 MED). Higher prevalence of comorbidities was seen in children with CF versus the comparison group across all ages. Across all ages, HCRU attributable to CF was substantial (higher hospitalization rates, more outpatient and emergency room visits, and greater use of prescription medications), and there were higher associated costs (all p values < .05), in COM and MED populations. HCRU and costs attributable to CF were highest for children aged 12-17 years.

CONCLUSIONS

Substantial HCRU and costs are evident among children with CF across all ages, starting as young as infancy, with highest HCRU and costs among adolescents. Effective treatments from an early age are needed for children with CF.

MRSA strains with distinct accessory genes predominate at different ages in cystic fibrosis

RATIONALE

Methicillin resistant Staphylococcus aureus (MRSA) is prevalent and consequential in cystic fibrosis (CF). Whole genome sequencing (WGS) could reveal genomic differences in MRSA associated with poorer outcomes or detect MRSA transmission.

OBJECTIVES

To identify MRSA genes associated with low lung function and potential MRSA transmission in CF.

METHODS

We collected 97 MRSA isolates from 74 individuals with CF from 2017 and performed short-read WGS. We determined sequence type (ST) and the phylogenetic relationship between isolates. We aligned accessory genes from 25 reference genomes to genome assemblies, classified isolates by accessory gene content, and correlated the accessory genome to clinical outcomes.

RESULTS

The most prevalent ST were ST5 (N = 55), ST8 (N = 15), and ST105 (N = 14). Closely related MRSA strains were shared by family members with CF, but rarely between unrelated individuals. Three clusters of MRSA were identified by accessory genome content. Cluster A, including ST5 and ST105, was highly prevalent at all ages. Cluster B, including ST8, was more limited to younger patients. Cluster C included 6 distantly related strains. Patients 20 years old and younger infected with Cluster A had lower forced expiratory volume in the first second (FEV₁ ) and higher sputum biomass compared to similar-aged patients with Cluster B.

CONCLUSIONS

In this CF cohort, we identified MRSA subtypes that predominate at different ages and differ by accessory gene content. The most prevalent cluster of MRSA, including ST5 and ST105, was associated with lower FEV₁ . ST8 MRSA was more common in younger patients and thus has the potential to rise in prevalence as these patients age.

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.

An Animated Functional Data Analysis Interface to Cluster Rapid Lung Function Decline and Enhance Center-Level Care in Cystic Fibrosis

Identifying disease progression through enhanced decision support tools is key to chronic management in cystic fibrosis at both the patient and care center level. Rapid decline in lung function relative to patient level and center norms is an important predictor of outcomes. Our objectives were to construct and utilize center-level classification of rapid decliners to develop an animated dashboard for comparisons within patients over time, multiple patients within centers, or between centers. A functional data analysis technique known as functional principal components analysis was applied to lung function trajectories from 18,387 patients across 247 accredited centers followed through the United States Cystic Fibrosis Foundation Patient Registry, in order to cluster patients into rapid decline phenotypes. Smaller centers (<30 patients) had older patients with lower baseline lung function and less severe rates of decline and had maximal decline later, compared to medium (30-150 patients) or large (>150 patients) centers. Small centers also had the lowest prevalence of early rapid decliners (17.7%, versus 24% and 25.7% for medium and large centers, resp.). The animated functional data analysis dashboard illustrated clustering and center-specific summaries of the rapid decline phenotypes. Clinical scenarios and utility of the center-level functional principal components analysis (FPCA) approach are considered and discussed.

Epidemiologic Study of Cystic Fibrosis: 25 years of observational research

The Epidemiologic Study of Cystic Fibrosis (ESCF) was a prospective observational study of over 32,000 people with cystic fibrosis (CF) from 250 clinical care sites in North America from 1994 to 2005. Begun as a pharmacovigilance study in connection with the approval of dornase alfa in 1993, ESCF was open to all people with CF treated at any participating site in the United States or Canada. In addition to obtaining safety and effectiveness data on dornase alfa, ESCF collected encounter-based data to characterize the natural history and management of CF with a special focus on lung disease. During the study, 32,178 patients reported at least one encounter, contributing 869,136 encounters, 622,592 pulmonary function tests, 432,896 cultures, and 118,563 pulmonary exacerbations treated with intravenous antibiotics. Although ESCF data collection concluded in 2005, through a collaboration with the U.S. Cystic Fibrosis Foundation Patient Registry, additional follow-up data through 2017 was available for two-thirds of patients. This allowed for updating of CF genotype and survival information. Fifty-six peer-reviewed publications (cited over 3600 times) resulted from this study. In this manuscript we summarize the published ESCF manuscripts in thematic groups with key study findings and brief comments, and speculate on how ESCF findings will inform future data registries and patient care practices.

Long-Term Impact of Ivacaftor on Healthcare Resource Utilization Among People with Cystic Fibrosis in the United States

INTRODUCTION

Ivacaftor was first approved in 2012 for the treatment of a select population of individuals with cystic fibrosis (CF), a rare, life-shortening genetic disease. Reductions in healthcare resource utilization (HCRU) associated with ivacaftor have been observed during limited follow-up and for selected outcomes in real-world studies. This study aimed to further describe the long-term impact of ivacaftor treatment on multiple measures of HCRU among people with CF (pwCF).

METHODS

This retrospective study used US commercial and Medicaid claims data from 2011-2018. We included pwCF ≥ 6 years of age with ≥ 1 claim for ivacaftor and 12 months of continuous health plan enrollment before ivacaftor initiation ("pre-ivacaftor" period) who also had 36 months of continuous enrollment and persistent ivacaftor use (i.e., no gap ≥ 90 days between refills) following initiation ("post-ivacaftor" period). We compared comorbidities occurring pre-ivacaftor versus the last 12 months post-ivacaftor. HCRU outcomes included medication use, inpatient admissions, and outpatient office visits. We compared medication use pre-ivacaftor versus the last 12 months post-ivacaftor and inpatient admissions and outpatient office visits pre-ivacaftor versus the post-ivacaftor period annualized across 36 months.

RESULTS

Seventy-nine pwCF met all criteria, including persistent ivacaftor use during the post-ivacaftor period. Ivacaftor treatment was associated with a significant reduction in pneumonia prevalence (10.1% vs. 26.6%; p < 0.001) and significantly fewer mean [SD] antibiotics claims (8.0 [7.3] vs. 12.3 [11.1]; p < 0.001) in the last 12 months post-ivacaftor versus pre-ivacaftor. In comparing the 36-month post-ivacaftor period to the pre-ivacaftor period, we also observed fewer mean [SD] annual inpatient admissions (0.2 [0.4] vs. 0.4 [0.7]), CF-related inpatient admissions (0.1 [0.2] vs. 0.2 [0.5]), and outpatient office visits (8.8 [4.9] vs. 9.9 [5.4]) (all, p < 0.05).

CONCLUSION

Long-term ivacaftor treatment reduced HCRU, consistent with trends observed in prior real-world studies. Our results support the sustained, long-term value of ivacaftor treatment in reducing CF burden.

Real-World Outcomes of Ivacaftor Treatment in People with Cystic Fibrosis: A Systematic Review

Cystic fibrosis (CF) is a rare, progressive, multi-organ genetic disease. Ivacaftor, a small-molecule CF transmembrane conductance regulator modulator, was the first medication to treat the underlying cause of CF. Since its approval, real-world clinical experience on the use of ivacaftor has been documented in large registries and smaller studies. Here, we systematically review data from real-world observational studies of ivacaftor treatment in people with CF (pwCF). Searches of MEDLINE and Embase identified 368 publications reporting real-world studies that enrolled six or more pwCF treated with ivacaftor published between January 2012 and September 2019. Overall, 75 publications providing data from 57 unique studies met inclusion criteria and were reviewed. Studies reporting within-group change for pwCF treated with ivacaftor consistently showed improvements in lung function, nutritional parameters, and patient-reported respiratory and sino-nasal symptoms. Benefits were evident as early as 1 month following ivacaftor initiation and were sustained over long-term follow-up. Decreases in pulmonary exacerbations, Pseudomonas aeruginosa prevalence, and healthcare resource utilization also were reported for up to 66 months following ivacaftor initiation. In studies comparing ivacaftor treatment to modulator untreated comparator groups, clinical benefits similarly were reported as were decreases in mortality, organ-transplantation, and CF-related complications. The safety profile of ivacaftor observed in these real-world studies was consistent with the well-established safety profile based on clinical trial data. Our systematic review of real-world studies shows ivacaftor treatment in pwCF results in highly consistent and sustained clinical benefit in both pulmonary and non-pulmonary outcomes across various geographies, study designs, patient characteristics, and follow-up durations, confirming and expanding upon evidence from clinical trials.

Non-contrast pulmonary perfusion MRI in patients with cystic fibrosis

PURPOSE

This study aimed to assess the feasibility of Self-gated Non-Contrast-Enhanced Functional Lung (SENCEFUL) MRI for detection of pulmonary perfusion deficits in patients with cystic fibrosis.

METHODS

Twenty patients with cystic fibrosis and 20 matched healthy controls underwent SENCEFUL-MRI at 1.5 T with reconstruction of perfusion and perfusion phase maps (i.e. comparable to pulse wave delays). Four blinded readers rated both types of maps separately followed by simultaneous assessment thereof. Perfusion phase data was plotted in histograms and a Peak-to-Offset ratio was calculated for comparison to subjective scoring and correlation (Spearman) to lung function parameters. Sensitivity, specificity and positive and negative predictive values were calculated for subjective scoring and Peak-to-Offset ratios. Intraclass correlation (ICC) was used to assess the interrater agreement.

RESULTS

Readers attributed pathological ratings 2.2-3.5 times more frequently to the CF-group. The sensitivity with regard to a correct assignment to CF was similar between ratings (perfusion only vs. perfusions phase only vs. simultaneous assessment: 0.54-0.56), while specificity increased from 0.75 to 0.85 for simultaneous assessment. ICC was 0.77-0.84 for subjective scoring. ROC-analysis of Peak-to-Offset ratios on a mean per-subject basis revealed a sensitivity of 0.75 and specificity of 0.85 (PPV 0.83, NPV 0.77). Functional pulmonary parameters indicative of bronchial obstruction and Peak-to-Offset ratios showed positive correlation (FEV1: 0.77; FEF75: 0.76).

CONCLUSIONS

SENCEFUL-MRI bears the potential for monitoring CF including disease-associated patterns of altered pulmonary perfusion. The proposed Peak-to-Offset ratio derived from pulmonary perfusion phase measurements could represent an objective future marker for perfusion impairment.

Evaluation of Inflammatory Biomarkers in Iranian Patients with Cystic Fibrosis

Background::

Cystic fibrosis (CF) is an autosomal recessive disease characterized by a progressive and recurrent lung infection.

Objective::

This study aimed to evaluate the levels of pro-inflammatory cytokines and their correlations with lung function in CF patients.

Methods::

A matched case-control study was conducted among 18 CF (children and adults) and 18 control patients (age and gender-matched) who were admitted to Masih Daneshvari Hospital (Tehran, Iran). The controls had no obvious inflammatory lung disease. The samples of bronchoalveolar lavage (BAL) fluid, serum, and sputum of participants were collected to determine concentrations of inflammatory cytokines such as interleukins (IL-8, IL-1β) and tumour necrosis factor- alpha (TNF-α) using enzyme-linked immunosorbent assay (ELISA). Spirometry was applied and functional pulmonary indices [forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)] were assessed.

Results::

The mean age of CF patients was 15.43 ± 5.970 years (range 4-24). The FVC in a majority of the CF patients (66.7%) was below 60% and only 33.3% of the patients exhibited normal or mild respiratory dysfunction. There were significant differences between FVC and FEV1 measurements before and after bronchoscopy. In addition, IL-8 levels in all three samples (serum, sputum, and BAL) of CF patients and levels of IL-1β and TNF-α in BAL and sputum samples of CF patients were significantly higher than the control group (p<0.001). However, increased cytokine levels were not associated with lung function.

Conclusion::

Increased IL-8 and TNF-α levels seemed to be associated with signs of clinical deterioration and might be useful as diagnostic markers.

The modified shuttle test as a predictor of risk for hospitalization in youths with cystic fibrosis: A two-year follow-up study: Modified shuttle test as a predictor of hospitalization

BACKGROUND

Patients with cystic fibrosis (CF) present exercise intolerance and episodes of pulmonary exacerbations. This study aimed to evaluate the association of the distance covered on the modified shuttle test (MST), as well as other clinical variables (anthropometry, chronic colonization by Pseudomonas aeruginosa, lung function), with the risk of hospitalization for pulmonary exacerbation.

METHODS

Cohort study including CF patients older than 6 years, from two specialized CF centers. All patients underwent a MST and a lung function test at the time of inclusion. Demographic, anthropometric and clinical data were collected. Free time until the first hospitalization, total days of hospitalization and use of antibiotics during the two years of follow-up were recorded.

RESULTS

Sixty-seven patients with a mean (SD) age of 12.4 (5.2) years and forced expiratory volume in the first second (FEV₁) of 78.7% (22.4) were included. The mean distance covered (m) in the MST was 775.6 (255.7) (73.4 ± 19.5% of predicted). The distance achieved (MST) was considered as the main independent variable to predict the risk of hospitalization (Cox HR 0.97, p = 0.029). Patients who walked a distance of less than 80% of predicted in the MST showed an increase of 3.9 (95%CI 1.0-15.3) in the relative risk for hospitalization and significantly higher total number of days of hospitalization (p = 0.022).

CONCLUSION

There is an association between the distance covered in the MST and the risk of hospitalization in youths with CF. Patients with reduced exercise capacity presented a 3.9 times increase in the relative risk for hospitalization due to pulmonary exacerbation.

Long-Term Outcomes in Real Life of Lumacaftor-Ivacaftor Treatment in Adolescents With Cystic Fibrosis

Background: The combination of the CFTR corrector lumacaftor (LUM) and potentiator ivacaftor (IVA) has been labeled in France since 2015 for F508del homozygote cystic fibrosis (CF) patients over 12 years. In this real-life study, we aimed (i) to compare the changes in lung function, clinical (e.g., body mass index and pulmonary exacerbations) and radiological parameters, and in sweat chloride concentration before and after initiation of LUM/IVA treatment; (ii) to identify factors associated with response to treatment; and (iii) to assess the tolerance to treatment. Materials and Methods: In this tri-center, non-interventional, and observational cohort study, children (12-18 years old) were assessed prospectively during the 2 years of therapy, and retrospectively during the 2 years preceding treatment. Data collected and analyzed for the study were exclusively extracted from the medical electronic system records of the patients. Results: Forty adolescents aged 12.0-17.4 years at LUM/IVA initiation were included. The lung function decreased significantly during and prior to treatment and increased after LUM/IVA initiation, becoming significant after 2 years of treatment. LUM/IVA significantly improved the BMI Z-score and sweat chloride concentration. By contrast, there was no significant change in exacerbation rates, antibiotic use, or CT scan scores. Age at LUM/IVA initiation was lower in good responders and associated with greater ppFEV1 change during the 2 years of treatment. LUM/IVA was well-tolerated. Conclusion: In F508del homozygote adolescents, real-life long-term LUM/IVA improved the ppFEV1 trajectory, particularly in the youngest patients, nutritional status, and sweat chloride concentration but not exacerbation rates or radiological scores. LUM/IVA was generally well-tolerated and safe.

Multivariate joint modeling to identify markers of growth and lung function decline that predict cystic fibrosis pulmonary exacerbation onset

Background

Attenuated decreases in lung function can signal the onset of acute respiratory events known as pulmonary exacerbations (PEs) in children and adolescents with cystic fibrosis (CF). Univariate joint modeling facilitates dynamic risk prediction of PE onset and accounts for measurement error of the lung function marker. However, CF is a multi-system disease and the extent to which simultaneously modeling growth and nutrition markers improves PE predictive accuracy is unknown. Furthermore, it is unclear which routinely collected clinical indicators of growth and nutrition in early life predict PE onset in CF.

Methods

Using a longitudinal cohort of 17,100 patients aged 6–20 years (US Cystic Fibrosis Foundation Patient Registry; 2003–2015), we fit a univariate joint model of lung-function decline and PE onset and contrasted its predictive performance with a class of multivariate joint models that included combinations of growth markers as additional submodels. Outcomes were longitudinal lung function (forced expiratory volume in 1 s of % predicted), percentiles of body mass index, weight-for-age and height-for-age and PE onset. Relevant demographic/clinical covariates were included in submodels. We implemented a univariate joint model of lung function and time-to-PE and four multivariate joint models including growth outcomes.

Results

All five joint models showed that declining lung function corresponded to slightly increased risk of PE onset (hazard ratio from univariate joint model: 0.97, P < 0.0001), and all had reasonable predictive accuracy (cross-validated area under the receiver-operator characteristic curve > 0.70). None of the growth markers alongside lung function as outcomes in multivariate joint modeling appeared to have an association with hazard of PE. Jointly modeling only lung function and PE onset yielded the most accurate (area under the receiver-operator characteristic curve = 0.75) and precise (narrowest interquartile range) predictions. Dynamic predictions were accurate across forecast horizons (0.5, 1 and 2 years) and precision improved with age.

Conclusions

Including growth markers via multivariate joint models did not yield gains in prediction performance, compared to a univariate joint model with lung function. Individualized dynamic predictions from joint modeling could enhance physician monitoring of CF disease progression by providing PE risk assessment over a patient’s clinical course.

Cystic fibrosis in the year 2020: A disease with a new face

The autosomal recessive disease cystic fibrosis (CF) was once untreatable and deadly in childhood, but now most patients survive to adulthood. Many countries have instituted CF newborn screening because early diagnosis improves outcome. CF research has greatly intensified following the discovery of the CF transmembrane conductance regulator (CFTR) gene, which has more than 2000 different mutations. For patients with common mutations like F508del, CFTR modulators are life transforming and may even prevent major complications if started early in childhood. For some patients with rare CFTR mutations, a treatment path still needs to be developed. Conclusion: This review provides a general update on CF, including screening and current and future treatment.

Staphylococcus aureus Pathogenicity in Cystic Fibrosis Patients-Results from an Observational Prospective Multicenter Study Concerning Virulence Genes, Phylogeny, and Gene Plasticity

Staphylococcus aureus and cystic fibrosis (CF) are closely interlinked. To date, however, the impact of S. aureus culture in CF airways on lung function and disease progression has only been elucidated to a limited degree. This analysis aims to identify bacterial factors associated to clinical deterioration. Data were collected during an observational prospective multi-center study following 195 patients from 17 centers. The average follow-up time was 80 weeks. S. aureus isolates (n = 3180) were scanned for the presence of 25 virulence genes and agr-types using single and multiplex PCR. The presence of specific virulence genes was not associated to clinical deterioration. For the agr-types 1 and 4, however, a link to the subjects’ clinical status became evident. Furthermore, a significant longitudinal decrease in the virulence gene quantity was observed. Analyses of the plasticity of the virulence genes revealed significantly increased plasticity rates in the presence of environmental stress. The results suggest that the phylogenetic background defines S. aureus pathogenicity rather than specific virulence genes. The longitudinal loss of virulence genes most likely reflects the adaptation process directed towards a persistent and colonizing rather than infecting lifestyle.

Cystic fibrosis knowledge and practice among primary care physicians in southwest region, Saudi Arabia

Introduction

Cystic fibrosis (CF) is a multisystem autosomal recessive disease that affects 1 in 4,000 newborns in the United States and has high mortality and morbidity. In the Middle East, there is no exact estimation of CF prevalence and the survival rate is almost 50% of the reported survival in the developed countries. In this study, I aimed to determine the CF knowledge and practice (CF-KP) among primary care physicians (PCPs) and to propose effective educational programs to recognize children who suffer from CF early on and refer them to appropriate tertiary centers.

Materials and Methods

This was a cross-sectional study among PCPs in the Aseer region. The principal investigator designed and formulated the used CF-KP questionnaire in this study. It was developed in the English language and distributed through Google and printed forms. Each question included right and wrong answers with the ability to choose more than one option. There were three categories for each question either answer completely, incompletely, or wrong answer.

Results

Fifty-one PCPs were recruited and successfully completed the questionnaire. Around two-thirds of the responders were less than 40 years old while few were older than 50 years. The majority of the responding doctors were male 82.4% (42 out of 51) and have been practicing clinical medicine more than 5 years after graduation. The overall knowledge score percent was 56.7% with a mean of 20.4, maximum 31, and minimum 4, while the overall practice score percent was 68% with a mean of 3.4 and maximum and minimum scores were 5 and 1, respectively.

Discussion

This study is the first study that assessed the CF-KP among PCPs in the Aseer region. The total score percent of knowledge and practice among the studied group were 56% and 68%, respectively. Around 20% of the responding physicians knew when to refer suspected cases of CF to a tertiary center for further diagnostic and therapeutic interventions. Most of the responders in this study did not know the long-term complications of CF and they did not think that it is a progressive disease and eventually cause death if untreated.

Conclusion

This study highlighted the need for extensive educational programs for the PCPs in order to improve early recognition of CF and start the appropriate management. In the era of CF modulators and correctors, CF providers should maximize the other therapies to improve the outcomes and prevent long-term morbidities and mortalities.

The association of pediatric cystic fibrosis-related diabetes screening on clinical outcomes by center: A CF patient registry study

BACKGROUND

Cystic fibrosis related diabetes (CFRD) has been associated with pulmonary function decline, nutritional status decline and increased mortality. In 2010, the CFRD Clinical Care Guideline were updated, recommending all patients with CF begin CFRD screening at 10 years old. This study uses CF Foundation Patient Registry to examine the impact of screening practices at centers across the United States from 2008 to 2015. We examined the association of screening practices and CFRD diagnosis at individual centers and trends in ppFEV1 and BMI percentile prior to and after diagnosis.

METHODS

The cohort was defined as patients with CF and without CFRD who turned 10 years old from 2009 to 2015. Centers were classified based on their CFRD screening rates. Kaplan-Meier curves summarized the distribution of age at CFRD diagnosis. Among patients diagnosed with CFRD, we examined differences in ppFEV1 and BMI percentile two years prior to diagnosis and two years post-diagnosis by clinic screening rate.

RESULTS

Of 3553 patients, 445 (13%) were diagnosed with CFRD. The average age of diagnosis was 13 years old. The screening rate of the patients' clinic was significantly associated with time to diagnosis (pvalue=0.0001). Among patients diagnosed with CFRD, clinics with lower screening rates of CFRD had steeper rates of pulmonary decline two years prior to diagnosis.

CONCLUSION

Centers that screen for CFRD more tend to diagnose a larger percent of patients with CFRD and at a younger age. Additionally, patients at centers with lower screening rates have faster rates of pulmonary decline prior to CFRD diagnosis.

Changes in Clinical Markers During A Short-Term Transfer Program of Adult Cystic Fibrosis Patients from Pediatric to Adult Care

Background:

Transition from child-oriented to adult-oriented health care in Cystic Fibrosis (CF) has become more important over recent decades as the survival of people with this disease has increased. The transition process usually begins in adolescence, with full transfer completed in early adulthood.

Objective:

This study investigated the impact of a short-term transfer program on clinical markers in an adult CF cohort still being managed by pediatricians.

Methods:

Clinically relevant data from the year before (T-1), the time of Transfer (T) and the year after the transfer (T+1) were analysed retrospectively.

Results:

39 patients (median age 29.0 years; 64% male) were transferred between February and December 2016. Lung function had declined significantly in the year before transfer (in % predicted: Forced Expiratory Volume in 1 second (FEV), 62.8 vs. 57.7, p <0.05; Forced Vital Capacity (FVC), 79.9 vs. 71.1, p<0.05), but remained stable in the year after transfer (in % predicted: FEV: 56.3; FVC 68.2). BMI was stable over the whole observational period. There was no relevant change in chronic lung infection with P. aeruginosa, Methicillin-Resistant Staphylococcus aureus (MRSA) and Burkholderia sp. during the observation period. The number of patient contacts increased significantly in the year after versus the year before transfer (inpatient: 1.51 vs. 2.51, p<0.05; outpatient: 2.67 vs. 3.41, p<0.05).

Conclusions:

Our data show that, within the framework of a structured transfer process, it is possible to transfer a large number of adult CF patients, outside a classic transition program, from a pediatric to an adult CF center in a short period of time, without any relevant changes in clinical markers and, stability.

FDA Breakthrough Therapy Designation: Evaluating the Quality of the Evidence behind the Drug Approvals

The United States Food and Drug Administration (FDA) has created approval pathways and designations to accelerate access to medications indicated for serious or life-threatening conditions with limited treatment options. Implemented in 2012, the most recent of these is the breakthrough therapy designation (BTD). The purpose of this article was to review the evidence surrounding approval of medications with nononcology indications approved with the BTD designation from 2012 to 2016. Fifteen medications were identified for eight conditions, ranging from conditions that are relatively common, such as chronic hepatitis C infection, to those that are extremely rare, such as lysosomal acid lipase deficiency. The quality of evidence behind these approvals was highly heterogeneous. Much remains unknown about the safety and efficacy of many agents approved through the BTD. Health care professionals should be aware of these limitations to better educate patients and other providers appropriately.

Association Between Fat-Free Mass and Pulmonary Function in Patients With Cystic Fibrosis: A Narrative Review

The association between body mass index (BMI) and pulmonary function in patients with cystic fibrosis (CF) is well established, yet BMI as the sole indicator of nutrition status fails to assess body composition, specifically fat-free mass (FFM). Reduced FFM is a characteristic of undernutrition and is associated with decreased pulmonary function. A critical review of the literature was undertaken to explore available evidence on the use of FFM derived from dual-energy X-ray absorptiometry (DXA), compared with BMI, to assess pulmonary function and thereby nutrition status in patients with CF. Four cross-sectional studies that met predefined inclusion and exclusion criteria were selected for review. Based on the evidence reviewed, reduced FFM was associated with reduced pulmonary function in both children and adults with CF. FFM was reduced among patients who may not otherwise be identified as at nutrition risk based on BMI alone. FFM, as compared with BMI, appears to be a better indicator of pulmonary function and nutrition status in patients with CF. Although future research is needed to identify and determine FFM measurements that are associated with improved pulmonary function and nutrition status in patients with CF, these findings highlight the potential value and clinical utility of using FFM measurements derived from DXA among patients with CF. Together, FFM and BMI may provide a more comprehensive picture of nutrition status during the nutrition assessment of the patient with CF.

Disease caused by non-tuberculous mycobacteria in children with cystic fibrosis

Non-tuberculous mycobacterial (NTM) (especially M. abscessus complex) infections pose a considerable challenge in the management of lung disease in patients with cystic fibrosis (CF). The apparent increase in prevalence is likely multifactorial. Emergent evidence of patient-to-patient transmission and isolation of highly resistant strains is a concern for all CF centers around the world. Treatment is often long and burdensome with multiple agents. Treatment side effects are frequent and can cause significant morbidity. Although consensus guidelines provide some direction, many units are faced with the challenges of: finding drug combinations for highly resistant strains; dealing with interruptions of treatment; discussing additional facilitating procedures in the form of gastrostomy and long-term vascular access devices; as well as supporting families emotionally and psychologically through the process.

Sleep-disordered breathing in cystic fibrosis pediatric subjects

Objectives

To describe the frequency of sleep-disordered breathing (SDB) in pediatric cystic fibrosis (CF) and to study associations between polysomnographic respiratory parameters and available clinical information.

Methods

This was a retrospective, cross-sectional study. The sample data were obtained from information recorded on patient charts in 2015 and 2016. The study included all individuals with CF aged from 2 to 20 years for whom records were available for polysomnography performed within the previous two years.

Results

Sixteen individuals with CF (mean age 11 ± 5.6 years old) were included. Polysomnographic respiratory parameter abnormalities were defined as an apnea-hypopnea index (AHI) exceeding one event per hour of sleep or an oxyhemoglobin saturation (SpO₂) nadir below 90%; observed in 10 subjects (62.5%). Forced expiratory volume in first second (FEV₁) was correlated (r=0.602, p=0.023) with mean sleep SpO₂. FEV₁ was also negatively correlated with sleep peak end-tidal carbon dioxide (EtpCO₂) (r=-0.645, p=0.024). Additionally, chronic airway colonization by Pseudomonas aeruginosa was associated with mean EtpCO₂ in non-REM sleep (p=0.024).

Discussion

SDB was frequently observed in this sample of children with CF. There was an association between CF respiratory disease progression markers and sleep breathing parameters in children. Sleep studies appear to be an important tool for assessment of the respiratory status of these individuals with CF, although further studies are needed, especially with carbon dioxide sleep analysis.

Improving Detection of Rapid Cystic Fibrosis Disease Progression-Early Translation of a Predictive Algorithm Into a Point-of-Care Tool

The clinical course of cystic fibrosis (CF) lung disease is marked by acute drops of lung function, defined clinically as rapid decline. As such, lung function is monitored routinely through pulmonary function testing, producing hundreds of measurements over the lifespan of an individual patient. Point-of-care technologies aimed at improving detection of rapid decline have been limited. Our aim in this early translational study is to develop and translate a predictive algorithm into a prototype prognostic tool for improved detection of rapid decline. The predictive algorithm was developed, validated and checked for 6-month, 1-year, and 2-year forecast accuracies using data on demographic and clinical characteristics from 30 879 patients aged 6 years and older who were followed in the U.S. Cystic Fibrosis Foundation Patient Registry from 2003 to 2015. Predictions of rapid decline based on the algorithm were compared to a detection algorithm currently being used at a CF center with 212 patients who received care between 2012-2017. The algorithm was translated into a prototype web application using RShiny, which resulted from an iterative development and refinement based on clinician feedback. The study showed that the algorithm had excellent predictive accuracy and earlier detection of rapid decline, compared to the current approach, and yielded a prototype platform with the potential to serve as a viable point-of-care tool. Future work includes implementation of this clinical prototype, which will be evaluated prospectively under real-world settings, with the aim of improving the pre-visit planning process for CF point of care. Likely extensions to other point-of-care settings are discussed.

The implementation of a cystic fibrosis annual review process in a tertiary paediatric hospital

We evaluated the implementation of a cystic fibrosis annual review process in a tertiary paediatric hospital. After implementation, there was demonstrated improvement in an important outcome measure-the use of inhaled mucolytic agents.

EMPIRE-CF: A phase II randomized placebo-controlled trial of once-daily, oral acebilustat in adult patients with cystic fibrosis - Study design and patient demographics

Inflammation causes irreparable damage in the cystic fibrosis (CF) lung. Despite high standards of care and the advent of new therapies, inflammation continues to cause significant loss of lung function and morbidity. Acebilustat is a once-daily, oral molecule with anti-inflammatory activity through the inhibition of LTA4 hydrolase and modulation of LTB4. It has potential to reduce lung function decline and pulmonary exacerbations in patients with CF and is currently being tested in a Phase II multicenter, randomized, double-blind, placebo-controlled, parallel-group study (EMPIRE-CF). Strict inclusion criteria based on modeling of the Cystic Fibrosis Foundation Patient Registry data were selected to enrich the trial with patients most likely to benefit from chronic anti-inflammatory therapy that reduces lung function decline. 200 patients between 18 and 30 years of age, with an FEV1 percent predicted (pp) ≥50%, and ≥1 exacerbation in the past year have been enrolled. Patients are randomized 1:1:1 to placebo, acebilustat 50 mg or 100 mg for 48 weeks, taken concomitantly with their current standard of care, and stratified based on concomitant CFTR modulator use, baseline FEV1pp (50% to 75% and >75%), and number of exacerbations in the past year (1 or >1). The primary endpoints are absolute change from baseline in FEV1pp and safety outcomes. Secondary endpoints include rate of pulmonary exacerbations and time to first pulmonary exacerbation. Biomarkers of inflammation will also be assessed. EMPIRE-CF is expected to identify the optimal patient population, dose, duration and endpoints for future acebilustat trials, and widen understanding of the drug's efficacy in patients with CF.

Sputum microbiota is predictive of long-term clinical outcomes in young adults with cystic fibrosis

BACKGROUND

Complex polymicrobial communities infect cystic fibrosis (CF) lower airways. Generally, communities with low diversity, dominated by classical CF pathogens, associate with worsened patient status at sample collection. However, it is not known if the microbiome can predict future outcomes. We sought to determine if the microbiome could be adapted as a biomarker for patient prognostication.

METHODS

We retrospectively assessed prospectively collected sputum from a cohort of 104 individuals aged 18-22 to determine factors associated with progression to early end-stage lung disease (eESLD; death/transplantation <25 years) and rapid pulmonary function decline (>-3%/year FEV₁ over the ensuing 5 years). Illumina MiSeq paired-end sequencing of the V3-V4 region of the 16S rRNA was used to define the airway microbiome.

RESULTS

Based on the primary outcome analysed, 17 individuals (16%) subsequently progressed to eESLD. They were more likely to have sputum with low alpha diversity, dominated by specific pathogens including Pseudomonas. Communities with abundant Streptococcus were observed to be protective. Microbial communities clustered together by baseline lung disease stage and subsequent progression to eESLD. Multivariable analysis identified baseline lung function and alpha diversity as independent predictors of eESLD. For the secondary outcomes, 58 and 47 patients were classified as rapid progressors based on absolute and relative definitions of lung function decline, respectively. Patients with low alpha diversity were similarly more likely to be classified as experiencing rapid lung function decline over the ensuing 5 years when adjusted for baseline lung function.

CONCLUSIONS

We observed that the diversity of microbial communities in CF airways is predictive of progression to eESLD and disproportionate lung function decline and may therefore represent a novel biomarker.

Using different methods to process forced expiratory volume in one second (FEV 1) data can impact on the interpretation of FEV 1 as an outcome measure to understand the performance of an adult cystic fibrosis centre: A retrospective chart review

Background: Forced expiratory volume in one second (FEV 1) is an important cystic fibrosis (CF) prognostic marker and an established endpoint for CF clinical trials. FEV 1 is also used in observation studies, e.g. to compare different centre's outcomes. We wished to evaluate whether different methods of processing FEV 1 data can impact on a centre's outcome. Methods: This is a single-centre retrospective analysis of routinely collected data from 2013-2016 which included 208 adults with CF. Year-to-year %FEV 1 change was calculated by subtracting best %FEV 1 at Year 1 from Year 2 (i.e. negative values indicate %FEV 1 decline), and compared using Friedman test. Three methods were used to process %FEV 1 data. First, %FEV 1 calculated with Knudson equation was extracted directly from spirometer machines. Second, FEV 1 volume were extracted then converted to %FEV 1 using clean height data and Knudson equation. Third, FEV 1 volume were extracted then converted to %FEV 1 using clean height data and GLI equation. In addition, %FEV 1 decline calculated using GLI equation was adjusted for baseline %FEV 1 to understand the impact of case-mix adjustment. Results: There was a trend of reduction in %FEV 1 decline with all three data processing methods but the magnitude of %FEV 1 decline differed. Median change in %FEV 1 for 2013-2014, 2014-2015 and 2015-2016 was -2.0, -1.0 and 0.0 respectively using %FEV 1 in Knudson equation whereas the median change was -1.1, -0.9 and -0.3 respectively using %FEV 1 in the GLI equation. A statistically significant p-value (0.016) was only obtained when using %FEV 1 in Knudson equation extracted directly from spirometer machines. Conclusions: Although the trend of reduction in %FEV 1 decline was robust, different data processing methods yielded varying results when %FEV 1 decline was compared using a standard related group non-parametric statistical test. Observational studies with %FEV 1 decline as an outcome measure should carefully consider and clearly specify the data processing methods used.

Using different methods to process forced expiratory volume in one second (FEV 1) data can impact on the interpretation of FEV 1 as an outcome measure to understand the performance of an adult cystic fibrosis centre: A retrospective chart review

Background: Forced expiratory volume in one second (FEV 1) is an important cystic fibrosis (CF) prognostic marker and an established endpoint for CF clinical trials. FEV 1 is also used in observation studies, e.g. to compare different centre's outcomes. We wished to evaluate whether different methods of processing FEV 1 data can impact on centre outcome. Methods: This is a single-centre retrospective analysis of routinely collected data from 2013-2016 among 208 adults. Year-to-year %FEV 1 change was calculated by subtracting best %FEV 1 at Year 1 from Year 2 (i.e. negative values indicate fall in %FEV 1), and compared using Friedman test. Three methods were used to process %FEV 1 data. First, %FEV 1 calculated with Knudson equation was extracted directly from spirometer machines. Second, FEV 1 volume were extracted then converted to %FEV 1 using clean height data and Knudson equation. Third, FEV 1 volume were extracted then converted to %FEV 1 using clean height data and GLI equation. In addition, year-to-year variation in %FEV 1 calculated using GLI equation was adjusted for baseline %FEV 1 to understand the impact of case-mix adjustment. Results: Year-to-year fall in %FEV 1 reduced with all three data processing methods but the magnitude of this change differed. Median change in %FEV 1 for 2013-2014, 2014-2015 and 2015-2016 was -2.0, -1.0 and 0.0 respectively using %FEV 1 in Knudson equation whereas the median change was -1.1, -0.9 and -0.3 respectively using %FEV 1 in the GLI equation. A statistically significant p-value (0.016) was only obtained when using %FEV 1 in Knudson equation extracted directly from spirometer machines. Conclusions: Although the trend of reduced year-to-year fall in %FEV 1 was robust, different data processing methods yielded varying results when year-to-year variation in %FEV 1 was compared using a standard related group non-parametric statistical test. Observational studies with year-to-year variation in %FEV 1 as an outcome measure should carefully consider and clearly specify the data processing methods used.

The Evolving Cystic Fibrosis Microbiome: A Comparative Cohort Study Spanning 16 Years

RATIONALE

The cystic fibrosis (CF) airways are infected with a diverse polymicrobial community.

OBJECTIVES

Understanding how changes in the CF microbiome have occurred over time, similar to the observed changes in the prevalence of cultured pathogens, is key in understanding the microbiome's role in disease.

METHODS

Drawing from a prospectively collected and maintained sputum biobank, we identified 45 patients with sputum samples collected between the ages of 18 and 21 years in three successive cohorts of adults transitioning to our CF clinic: A (1997-2000), B (2004-2007), and C (2010-2013). Patient demographics, clinical status, and medications were collected from detailed chart review. Microbial communities were assessed by Ilumina MiSeq sequencing of the variable 3 (V3) region of the 16S rDNA.

RESULTS

The three cohorts were similar with respect to baseline demographics. There was a trend toward improved health and use of disease-modifying therapies in each successive cohort. Shannon diversity increased in the most recent cohort, suggesting an increase in the diversity of organisms between cohorts. Furthermore, the proportion of samples with Pseudomonas-dominated communities decreased over time, whereas Streptococcus increased. Although β-diversity was associated with transition cohort, the greatest predictor of diversity remained lung function. Furthermore, core microbiome constituents were preserved across cohorts.

CONCLUSIONS

Modest changes in the composition and structure of the microbiome of three successive cohorts of young adults with CF were observed, occurring in parallel with successive improvements in clinical status. Importantly, however, the core microbiome constituents were preserved across cohorts.

Understanding Pseudomonas status among adults with cystic fibrosis: a real-world comparison of the Leeds criteria against clinicians' decision

Pseudomonas aeruginosa status influences cystic fibrosis (CF) clinical management but no 'gold standard' definition exists. The Leeds criteria are commonly used but may lack sensitivity for chronic P. aeruginosa. We compared clinicians' decision with the Leeds criteria in three adult CF centres. Two independent prospective datasets (Sheffield dataset, n = 185 adults; ACtiF pilot dataset, n = 62 adults from two different centres) were analysed. Clinicians involved in deciding P. aeruginosa status were blinded to the study objectives. Clinicians considered more adults with CF to have chronic P. aeruginosa infection compared to the Leeds criteria. This was more so for the Sheffield dataset (106/185, 57.3% with clinicians' decision vs. 80/185, 43.2% with the Leeds criteria; kappa coefficient between these two methods 0.72) compared to the ACtiF pilot dataset (34/62, 54.8% with clinicians' decision vs. 30/62, 48.4% with the Leeds criteria; kappa coefficient between these two methods 0.82). However, clinicians across different centres were relatively consistent once age and severity of lung disease, as indicated by the type of respiratory samples provided, were taken into account. Agreement in P. aeruginosa status was similar for both datasets among adults who predominantly provided sputum samples (kappa coefficient 0.78) or adults > 25 years old (kappa coefficient 0.82). Across three different centres, clinicians did not always agree with the Leeds criteria and tended to consider the Leeds criteria to lack sensitivity. Where disagreement occurred, clinicians tended to diagnose chronic P. aeruginosa infection because other relevant information was considered. These results suggest that a better definition for chronic P. aeruginosa might be developed by using consensus methods to move beyond a definition wholly dependent on standard microbiological results.

Early Detection of Rapid Cystic Fibrosis Disease Progression Tailored to Point of Care: A Proof-of-Principle Study

Slowing cystic fibrosis (CF) lung disease progression is crucial to survival, but point-of-care technologies aimed at early detection-and possibly prevention-of rapid lung function decline are limited. This proof-of-principle study leverages a rich national patient registry and follow-up data on a local CF cohort to build an algorithm and prototype prognostic tool aimed at early detection of rapid lung function decline. The algorithm was developed using a novel longitudinal analysis of lung function (measured as forced expiratory volume in 1 s of % predicted, FEV1). Covariates included clinical and demographic characteristics selected from the registry based on information criterion. Preliminary assessment of algorithm performance suggested excellent predictive accuracy and earlier detection of rapid decline than standard of care being applied at a local center. Graphical displays were presented and evaluated for clinical utility. Predictions from the algorithms and chosen graphical displays were translated into a prototype web application using RShiny and underwent iterative development based on clinician feedback. This paper suggests that the algorithm and its translation could offer a means for earlier detection and treatment of rapid decline, providing clinicians with a viable point-of-care technology to intervene prior to irreversible lung damage.

Functional lung MRI for regional monitoring of patients with cystic fibrosis

Purpose

To test quantitative functional lung MRI techniques in young adults with cystic fibrosis (CF) compared to healthy volunteers and to monitor immediate treatment effects of a single inhalation of hypertonic saline in comparison to clinical routine pulmonary function tests.

Materials and methods

Sixteen clinically stable CF patients and 12 healthy volunteers prospectively underwent two functional lung MRI scans and pulmonary function tests before and 2h after a single treatment of inhaled hypertonic saline or without any treatment. MRI-derived oxygen enhanced T₁ relaxation measurements, fractional ventilation, first-pass perfusion parameters and a morpho-functional CF-MRI score were acquired.

Results

Compared to healthy controls functional lung MRI detected and quantified significantly increased ventilation heterogeneity in CF patients. Regional functional lung MRI measures of ventilation and perfusion as well as the CF-MRI score and pulmonary function tests could not detect a significant treatment effect two hours after a single treatment with hypertonic saline in young adults with CF (p>0.05).

Conclusion

This study shows the feasibility of functional lung MRI as a non-invasive, radiation-free tool for monitoring patients with CF.