Lung clearance index: evidence for use in clinical trials in cystic fibrosis

Mild airways obstruction: spirometric diagnostic pitfalls and solutions

PURPOSE OF REVIEW

Spirometry is a validated tool in the diagnosis of obstructive airways disease. However, it may be insufficiently sensitive in detecting airflow limitation in the small airways. This review highlights common clinical scenarios wherein airflow limitation may be missed or overlooked.

RECENT FINDINGS

This article covers recent literature on the interpretation of lung function test, focusing on detection of mild obstructive airways disease. It also sheds light on the contextual difficulties of defining mild airflow limitation on spirometry.

SUMMARY

We highlight the consensus definition of mild obstructive airways disease and emphasize that this definition does not necessarily mean mild in certain disease-specific contexts. Several spirometric findings outside of a reduced forced expiratory volume in one second/forced vital capacity ratio should raise suspicion of mild obstruction.

The effect of inspiratory muscle training in PCD and CF patients: A pilot study

BACKGROUND

Effective work of breathing and bronchial hygiene requires synergy of inspiratory and expiratory muscles. Inspiratory muscle training (IMT) is a part of pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD). There is some evidence of its efficacy in cystic fibrosis (CF) and, recently, in long COVID-19. We are not aware of studies on IMT in primary ciliary dyskinesia (PCD). Our aim was to assess the effect of IMT on respiratory muscle strength and pulmonary function in PCD and CF patients.

METHODS

A single center pilot study. Spirometry, lung clearance index (LCI), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were measured at baseline (visit 1), after a month of IMT with ®POWERbreathe (visit 2), and at follow-up (visit 3).

RESULTS

The cohort included 27 patients (19 PCD, 8 CF); mean age 18.4 ± 9.8 years. After a month of IMT, there was a significant increase in MIP and MIP% (6.19-7.44, p = .015; and 81.85%-100.41%, p = .046, respectively), which was sustained at visit 3. Compliance ≥90% led to higher improvement in MIP. In sub-group analysis, improvement in MIP and MIP% remained significant for PCD patients (p = .026 and p = .049, respectively). No significant changes were found in spirometry, MEP or LCI.

CONCLUSIONS

IMT was well-tolerated and led to improved inspiratory muscle strength in PCD patients. The clinical implication of improved MIP should be further investigated. Larger, long-term studies are needed to evaluate long-term effects of IMT on pulmonary function, respiratory muscle strength, pulmonary exacerbations, and quality of life.

Inhalation Pharmacodynamics

Pharmacodynamics (PD) is discussed in relation to inhalation exposure to inhaled pharmaceutical and toxic agents. Clearly PD is closely related to pharmacokinetics, and this relation is illustrated with reference to inhaled insulin. PD can be related to pharmacologic responses, and some examples are cited. However, PD can also be thought of as the improvement or deterioration in lung disease state. Some of the major PD endpoints, including histopathology, pulmonary function, and bronchoalveolar lavage are reviewed. Brief reference is also given to other specialty biomarkers of PD response.

CFTR modulator therapy: transforming the landscape of clinical care in cystic fibrosis

Following discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989 and subsequent elucidation of the varied CFTR protein abnormalities that result, a new era of cystic fibrosis management has emerged-one in which scientific principles translated from the bench to the bedside have enabled us to potentially treat the basic defect in the majority of children and adults with cystic fibrosis, with a resultant burgeoning adult cystic fibrosis population. However, the long-term effects of these therapies on the multiple manifestations of cystic fibrosis are still under investigation. Understanding the effects of modulators in populations excluded from clinical trials is also crucial. Furthermore, establishing appropriate disease measures to assess efficacy in the youngest potential trial participants and in those whose post-modulator lung function is in the typical range for people without chronic lung disease is essential for continued drug development. Finally, recognising that a health outcome gap has been created for some people and widened for others who are not eligible for, cannot tolerate, or do not have access to modulators is important.

Pulmonary Function Tests in the Evaluation of Early Lung Disease in Cystic Fibrosis

BACKGROUND

Properly evaluating respiratory system dysfunction is essential in children with cystic fibrosis (CF). This prospective study aimed to assess the course of early lung disease based on multiple breath nitrogen washout (MBNW), impulse oscillometry (IOS), and conventional techniques, such as spirometry and body plethysmography.

METHODS

Over a 2 year recruitment period, subjects with CF aged 7-18 performed pulmonary function tests (PFTs). Moreover, the nutritional and microbiological status, frequency of pulmonary exacerbations (PExs), and patients' health-related quality of life (HRQoL) were assessed.

RESULTS

The mean age of the children (n = 69) was 14.09 ± 3.26 years; F/M 37/32. Spirometry-based diagnoses of normal lung function (forced expiratory volume in 1 s, FEV₁ ≥ 90%pred), mild (FEV₁ 70-89%pred) and moderate (FEV₁ 40-69%pred) lung diseases were established in 34 (49.3%), 25 (36.2%), and 10 (14.5%) patients, respectively. An elevated lung clearance index (LCI > 6.98) was observed in 85% of the subjects with normal FEV₁. The presence of Pseudomonas aeruginosa infection (n = 16) and the number of PExs treated with IV antibiotics were associated with significantly worse PFT results.

CONCLUSIONS

MBNW and IOS are more helpful tools than conventional techniques in assessing early lung disease in CF. LCI is a more useful parameter for detecting functional abnormalities than FEV₁ in school-age children.

How Does the Corrected Exhalyzer Software Change the Predictive Value of LCI in Pulmonary Exacerbations in Children with Cystic Fibrosis?

Aim: Recently, the most commonly used for multiple breath washout device, the Exhalyzer D, has been shown to overestimate lung clearance index (LCI) results due to a software error. Our study aimed to compare the predictive values of LCI in the CF pulmonary exacerbations (PE) calculated with the updated (3.3.1) and the previous (3.2.1) version of the Spiroware software. Materials and Methods: The measurements were performed during 259 visits in CF pediatric patients. We used 39ΔPE pairs (PE preceded by stable visit) and 138ΔS pairs (stable visit preceded by stable visit) to compare the LCI changes during PE. The areas under the receiver operating curves (AUC^ROC) and odds ratios were calculated based on the differences between ΔPEs and ΔSs. The exacerbation risk was estimated using a logistic regression model with generalized estimating equations (GEE). Results: There were statistically significant differences in LCI 2.5% median values measured using the two versions of the software in the stable condition but not during PE. The AUC^ROC for changes between the two consecutive visits for LCI did not change significantly using the updated Spiroware software. Conclusions: Despite the lower median values, using the recalculated LCI values does not influence the diagnostic accuracy of this parameter in CF PE.

BEAT CF pulmonary exacerbations core protocol for evaluating the management of pulmonary exacerbations in people with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a rare, inherited, life-limiting condition predominantly affecting the lungs, for which there is no cure. The disease is characterized by recurrent pulmonary exacerbations (PEx), which are thought to drive progressive lung damage. Management of these episodes is complex and generally involves multiple interventions targeting different aspects of disease. The emergence of innovative trials and use of Bayesian statistical methods has created renewed opportunities for studying heterogeneous populations in rare diseases. Here, we present the protocol for the BEAT CF PEx cohort, a prospective, multi-site, perpetual, platform enrolling adults and children with CF. The BEAT CF PEx cohort will be used to evaluate the comparative effectiveness of interventions for the treatment of PEx requiring intensive therapy (PERITs), with a primary focus on short-term improvements in lung function. This will be achieved through the conduct of cohort-nested studies, including adaptive clinical trials, within the BEAT CF PEx cohort. This protocol will outline key features of the BEAT CF PEx cohort, including the design, implementation, data collection and management, governance and analysis, and dissemination of results.

METHODS

This platform will be conducted across multiple sites, commencing with CF treatment centers in Australia. People of all ages with a clinical diagnosis of CF will be eligible to participate, except those who have previously received a lung transplant. Data including demographic and clinical information, treatment details, and outcomes (including safety, microbiology, and patient-reported outcome measures including quality of life scores) will be systematically collected and securely stored via a digital centralized trial management system (CTMS). The primary endpoint is the absolute change in the percentage predicted forced expiratory volume in 1 s (ppFEV₁) from the commencement of intensive therapy to 7 to 10 days afterwards.

DISCUSSION

The BEAT CF PEx cohort will report clinical, treatment, and outcome data for PEx among people with CF and is intended to serve as a core (master) protocol for future nested, interventional trials evaluating treatment(s) for these episodes. The protocols for nested sub-studies are beyond the scope of this document and will be reported separately.

TRIAL REGISTRATION

ANZCTR BEAT CF Platform - ACTRN12621000638831. Registration date: Sept. 26, 2022.

Effect of Trikafta on bone density, body composition and exercise capacity in CF: A pilot study

BACKGROUND

While the positive effect of Trikafta on cystic fibrosis (CF) pulmonary disease is well established, there is limited data about its effect on bone mineral density (BMD), body composition and exercise capacity.

METHODS

A pilot single center study. BMD and body composition were measured three months after the initiation of Trikafta (study group) and compared to values obtained 2 years earlier. CF patients not treated with Trikafta, for whom BMD was measured 2 years apart, served as controls. Spirometry, lung clearance index (LCI), sweat test, six-min walk test (6MWT) and cardio-pulmonary exercise test (CPET) were performed before and three months after the initiation of Trikafta.

RESULTS

Nine study patients, aged 18.6 ± 4.7 years, and nine controls. For the study group, BMI and hip and spine BMD increased significantly (19.4 ± 2.6 to 20.3 ± 2.19 BMI, p = 0.05; 0.73 ± 0.098 to 0.81 ± 0.12 gr/cm² hip, p = 0.017; 0.76 ± 0.14 to 0.82 ± 0.14 gr/cm² spine, p = 0.025). For the control group, there was no difference in hip or spine BMD. Lean body mass, %fat z-score and fat mass/height² z-score increased significantly (34770.23 ± 10521.21 to 37430.16 ± 10330.09gr, p = 0.017; -0.8 ± 0.75 to 0.46 ± 0.58, p = 0.012; and -0.98 ± 0.66 to -0.04 ± 0.51, p = 0.025, respectively). 6MWT improved from 541.1 ± 48.9 to 592.9 ± 54.5 m (p = 0.046). As expected, FEV1%pred increased (p = 0.008) and sweat chloride decreased significantly (p = 0.017). In CPET, VE/VCO₂ improved, indicating better ventilatory efficiency.

CONCLUSIONS

To the best of our knowledge, this is the first study evaluating the metabolic effects of Trikafta. The results are encouraging and offer hope beyond the well-established effect on pulmonary disease. Larger long-term studies are warranted to unpin the underlying physiological mechanisms.

Role of the Physical Therapist in Cystic Fibrosis Care

In looking back on 2020 and 2021, this Perspective reflects on the monumental impacts of the rollout of cystic fibrosis (CF) transmembrane conductance regulator highly effective modulator therapies and the COVID-19 pandemic on the management of CF. Advancements in the clinical management of people with CF have been both enormous and rapid, and physical therapists specializing in the care of people with CF have been at the forefront of driving this evolution in care. This year sees the 30th anniversary of the UK Association of Chartered Physiotherapists in Cystic Fibrosis and, as is inevitable in reaching such milestones, thoughts have turned to origins, role, impacts, and the future. With the changing demographics of the population of people with CF after the introduction of highly effective modulator therapies, potentially with fewer secondary complications, the future role of the physical therapist who specializes in CF is in question. This Perspective reflects on and highlights the role of physical therapy within CF and provides insights into how physical therapists and respiratory therapists can evolve their roles to ensure relevance for the future.

Emerging Approaches to Monitor and Modify Care in the Era of Cystic Fibrosis Transmembrane Conductance Regulators

As we characterize the clinical benefits of highly effective modulator therapy (HEMT) in the cystic fibrosis (CF) population, our paradigm for treating and monitoring disease continues to evolve. More sensitive approaches are necessary to detect early disease and clinical progression. This article reviews evolving strategies to assess disease control and progression in the HEMT era. This article also explores developments in pulmonary function monitoring, advanced respiratory imaging, tools for the collection of patient-reported outcomes, and their application to profile individual responses, guide therapeutic decisions, and improve the quality of life of people with CF.

The Impact of Highly Effective Modulator Therapy on Cystic Fibrosis Microbiology and Inflammation

Highly effective cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulator therapy (HEMT) corrects the underlying molecular defect causing CF disease. HEMT decreases symptom burden and improves clinical metrics and quality of life for most people with CF (PwCF) and eligible cftr mutations. Improvements in measures of pulmonary health suggest that restoration of function of defective CFTR anion channels by HEMT not only enhances airway mucociliary clearance, but also reduces chronic pulmonary infection and inflammation. This article reviews the evidence for how HEMT influences the dynamic and interdependent processes of infection and inflammation in the CF airway, and what questions remain unanswered.

Estimating the minimum sample size for interventional and observational studies using the lung clearance index as an endpoint✰

BACKGROUND

With the increasing availability of highly effective modulators for people living with cystic fibrosis (CF), there is a need to re-design research studies to reflect the changing epidemiology of the CF population. The lung clearance index (LCI), a sensitive physiological measure of lung function, may be ideally suited as an endpoint in the era of CF modulator therapies. In this study we describe study design considerations for implementing LCI into interventional and observational research.

METHODS

Simulations were used to estimate the required sample size to detect a range of treatment effects for interventional studies (including cross-over trials) and to track lung disease progression in observational studies.

RESULTS

Using published treatment effects to inform the design of prospective studies can lead to inefficient study designs. Large improvements in LCI for a few individuals can skew results and can influence interpretations of treatment effects. Adjusting for baseline LCI can help to improve the efficiency of a study. Compared to the forced expiratory volume in 1 second (FEV₁), analysis using LCI as an endpoint requires as little as one third of the total sample size.

CONCLUSIONS

Planning of prospective studies that include LCI as an endpoint need to consider baseline LCI and disease severity of the study population; whereas interpretation of results needs to consider whether a few individuals skew the overall treatment effect.

The effect of probiotic administration on metabolomics and glucose metabolism in CF patients

BACKGROUND AND OBJECTIVES

Cystic fibrosis (CF)-related diabetes (CFRD) affects 50% of CF adults. Gut microbial imbalance (dysbiosis) aggravates their inflammatory response and contributes to insulin resistance (IR). We hypothesized that probiotics may improve glucose tolerance by correcting dysbiosis.

METHODS

A single-center prospective pilot study assessing the effect of Vivomixx® probiotic (450 billion/sachet) on clinical status, spirometry, lung clearance index (LCI), and quality of life (QOL) questionnaires; inflammatory parameters (urine and stool metabolomics, blood cytokines); and glucose metabolism (oral glucose tolerance test [OGTT]), continuous glucose monitoring [CGM], and homeostasis model assessment of IR (HOMA-IR) in CF patients.

RESULTS

Twenty-three CF patients (six CFRD), mean age 17.7 ± 8.2 years. After 4 months of probiotic administration, urinary cysteine (p = 0.018), lactulose (p = 0.028), arabinose (p = 0.036), mannitol (p = 0.041), and indole 3-lactate (p = 0.046) significantly increased, while 3-methylhistidine (p = 0.046) and N-acetyl glutamine (p = 0.047) decreased. Stool 2-Hydroxyisobutyrate (p = 0.022) and 3-methyl-2-oxovalerate (p = 0.034) decreased. Principal component analysis, based on urine metabolites, found significant partitions between subjects at the end of treatment compared to baseline (p = 0.004). After 2 months of probiotics, the digestive symptoms domain of Cystic Fibrosis Questionnaire-Revised improved (p = 0.007). In the nondiabetic patients, a slight decrease in HOMA-IR, from 2.28 to 1.86, was observed. There was no significant change in spirometry results, LCI, blood cytokines and CGM.

CONCLUSIONS

Changes in urine and stool metabolic profiles, following the administration of probiotics, may suggest a positive effect on glucose metabolism in CF. Larger long-term studies are needed to confirm our findings. Understanding the interplay between dysbiosis, inflammation, and glucose metabolism may help preventing CFRD.

Going the Extra Mile: Why Clinical Research in Cystic Fibrosis Must Include Children

This is an exciting time for research and novel drug development in cystic fibrosis. However, rarely has the adage, “Children are not just little adults” been more relevant. This article is divided into two main sections. In the first, we explore why it is important to involve children in research. We discuss the potential benefits of understanding a disease and its treatment in children, and we highlight that children have the same legal and ethical right to evidence-based therapy as adults. Additionally, we discuss why extrapolation from adults may be inappropriate, for example, medication pharmacokinetics may be different in children, and there may be unpredictable adverse effects. In the second part, we discuss how to involve children and their families in research. We outline the importance and the complexities of selecting appropriate outcome measures, and we discuss the role co-design may have in improving the involvement of children. We highlight the importance of appropriate staffing and resourcing, and we outline some of the common challenges and possible solutions, including practical tips on obtaining consent/assent in children and adolescents. We conclude that it is unethical to simply rely on extrapolation from adult studies because research in young children is challenging and that research should be seen as a normal part of the paediatric therapeutic journey.

The effect of inhaled hypertonic saline on lung structure in children aged 3-6 years with cystic fibrosis (SHIP-CT): a multicentre, randomised, double-blind, controlled trial

BACKGROUND

In the Saline Hypertonic in Preschoolers (SHIP) study, inhaled 7% hypertonic saline improved the lung clearance index in children aged 3-6 years with cystic fibrosis, but it remained unclear whether improvement is also seen in structural lung disease. We aimed to assess the effect of inhaled hypertonic saline on chest CT imaging in children aged 3-6 years with cystic fibrosis.

METHODS

Children with cystic fibrosis were enrolled in this multicentre, randomised, double-blind, controlled study at 23 cystic fibrosis centres in Spain, Denmark, the Netherlands, Italy, France, Belgium, the USA, Canada, and Australia. Eligible participants were children aged 3-6 years who were able to cooperate with chest CT imaging and comply with daily nebuliser treatment. Participants were randomly assigned 1:1 to receive inhaled 2 puffs of 100 μg salbutamol followed by 4mL of either 7% hypertonic saline or 0·9% isotonic saline twice per day for 48 weeks. Randomisation was stratified by age in North America and Australia, and by age and country in Europe. Chest CTs were obtained at baseline and 48 weeks and scored using the Perth-Rotterdam Annotated Grid Morphometric Analysis for Cystic Fibrosis (PRAGMA-CF) method. The primary outcome was the difference between groups in the percentage of total lung volume occupied by abnormal airways (PRAGMA-CF %Disease) measured by chest CT at 48 weeks. Analysis was by intention-to-treat. This study is registered with Clinicaltrials.gov, NCT02950883.

FINDINGS

Between May 24, 2016, and Dec 18, 2019, 134 children were assessed for inclusion. 18 patients were excluded (nine had incomplete or unsuccessful chest CT at enrolment visit, two could not comply with CT training, two had acute respiratory infection, two withdrew consent, two for reasons unknown, and one was already on hypertonic saline). 116 participants were enrolled and randomly assigned to hypertonic saline (n=56) or isotonic saline (n=60). 12 patients dropped out of the study (seven in the hypertonic saline group and five in the isotonic saline group). Mean PRAGMA-CF %Disease at 48 weeks was 0·88% (95% CI 0·60-1·16) in the hypertonic saline group and 1·55% (1·25-1·84) in the isotonic saline group (mean difference 0·67%, 95% CI 0·26-1·08; p=0·0092) based on a linear regression model adjusted for baseline %Disease values and baseline age. Most adverse events in both groups were rated as mild, and the most common adverse event in both groups was cough.

INTERPRETATION

Inhaled hypertonic saline for 48 weeks had a positive effect on structural lung changes in children aged 3-6 years with cystic fibrosis relative to isotonic saline. This is the first demonstration of an intervention that alters structural lung disease in children aged 3-6 years with cystic fibrosis.

FUNDING

Cystic Fibrosis Foundation.

Predictive value of impulse oscillometry and multiple breath washout parameters in pediatric patients with cystic fibrosis pulmonary exacerbation

BACKGROUND

Pulmonary exacerbations (PE) tend to complicate the course of cystic fibrosis (CF) and worsen the disease prognosis. One of the diagnostic criteria for an exacerbation is the forced expiratory volume in the first second (FEV₁ ) decline. Not all children, however, are able to perform spirometry. Therefore, the aim of this study was to evaluate alternative lung function tests in the diagnosis of PE.

METHODS

We assessed retrospectively the results of impulse oscillometry (IOS) and lung clearance index in multiple breath washout (MBW) during 259 visits in 47 CF paediatric patients. The differences in the results were compared between patients diagnosed with PE (ΔPE) and those in stable condition (ΔS).

RESULTS

Among the whole group of patients, we found significant differences between the changes during exacerbation (ΔPEs) and stable condition (ΔSs) values for lung clearance index (LCI), S_acin , R5Hz, R5-20Hz, X10Hz, AX, and Fres. The predictive values of Fres and X10Hz in IOS (AUC^ROC 0.71 both parameters) were higher than those of LCI (AUC^ROC 0.67). There was no difference in the predictive values (AUC^ROC ) of Δ LCI and IOS parameters in the subgroups of patients stratified based on FEV₁ z-score cut-off value of -1.64. In both groups of patients, predictive values of LCI were slightly lower than of IOS parameters (AUC 0.66 for LCI vs. 0.69 for both ΔX10Hz z-score and Δ Fres z-score in patients with FEV₁ z-score ≥-1.64 and AUC 0.67 for LCI vs 0.69 for both ΔX10Hz zscore and Δ Fres zscore in patients with FEV₁ <1.64.

CONCLUSIONS

Both IOS and MBW measurements are useful in the assessment of pediatric CF patients with PE. LCI has a similar predictive value to IOS in children with CF independently of their FEV₁ value.

Clinimetric analysis of outcome measures for airway clearance in people with cystic fibrosis: a systematic review

Background:

Airway clearance techniques (ACTs) are integral to cystic fibrosis (CF) management. However, there is no consensus as to which outcome measures (OMs) are best for assessing ACT efficacy.

Objectives:

To summarise OMs that have been assessed for their clinimetric properties (including validity, feasibility, reliability, and reproducibility) within the context of ACT research in CF.

Design and Methods:

A systematic review was conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA) standards. Any parallel or cross-over randomised controlled trial (RCT) investigating outcome measures for ACT in the CF population were eligible for inclusion. The search was performed in five medical databases, clinicaltrials.gov, and abstracts from international CF conferences. The authors planned to independently assess study quality and risk of bias using the COnsensus-based Standards for the selection of health status Measurement InstrumeNts (COSMIN) risk of bias checklist with external validity assessment based upon study details (participants and study intervention). Two review authors (GS and MJ) independently screened search results against inclusion criteria, and further data extraction were planned but not required.

Results:

No completed RCTs from the 187 studies identified met inclusion criteria for the primary or post hoc secondary objective. Two ongoing trials were identified.

Discussion and conclusion:

This empty systematic review highlights that high-quality RCTs are urgently needed to investigate and validate the clinimetric properties of OMs used to assess ACT efficacy. With the changing demographics of CF combined with the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies, an accurate assessment of the current benefit of ACT or the effect of ACT withdrawal is a high priority for clinical practice and future research; OMs which have been validated for this purpose are essential.

Registration:

This systematic review was registered on the PROSPERO database (CRD42020206033).

Multiple Breath Washout for Early Assessment of Pulmonary Complications in Patients With Primary Antibody Deficiencies: An Observational Study in Pediatric Age

BACKGROUND

In primary antibody deficiencies (PADs), pulmonary complications are the main cause of morbidity, despite immunoglobulin substitutive therapy, antibiotic treatment of exacerbations, and respiratory physiotherapy. Current Italian recommendations for surveillance of PADs respiratory complications include an annual assessment of spirometry and execution of chest high-resolution computed tomography (HRCT) every 4 years.

OBJECTIVE

This study aimed to evaluate the effectiveness of the lung clearance index (LCI) as an early marker of lung damage in patients with PADs. LCI is measured by multiple breath washout (MBW), a non-invasive and highly specific test widely used in patients with cystic fibrosis (CF).

METHODS

Pediatric patients with PADs (n = 17, 10 male, 7 female, and age range 5-15 years) underwent baseline assessment of lung involvement with chest HRCT, spirometry, and multiple breath nitrogen washout. Among them, 13 patients were followed up to repeat HRCT after 4 years, while performing pulmonary function tests annually. Their baseline and follow-up LCI and forced expiratory volume at 1 s (FEV1) values were compared, taking HRCT as the gold standard, using logistic regression analysis.

RESULTS

Lung clearance index [odds ratio (OR) 2.3 (confidence interval (CI) 0.1-52) at baseline, OR 3.9 (CI 0.2-191) at follow-up] has a stronger discriminating power between altered and normal HRCT rather than FEV1 [OR 0.6 (CI 0.2-2) at baseline, OR 1.6 (CI 0.1-13.6) at follow-up].

CONCLUSION

Within the context of a limited sample size, LCI seems to be more predictive of HRCT alterations than FEV1 and more sensitive than HRCT in detecting non-uniform ventilation in the absence of bronchiectasis. A study of a larger cohort of pediatric patients followed longitudinally in adulthood is needed to challenge these findings.

A Comparative Analysis of Pricing and Reimbursement of Cystic Fibrosis Transmembrane Conductance Regulator Modulators in Europe

Objectives: Cystic fibrosis transmembrane conductance regulator (CFTR) modulators, Kalydeco® (ivacaftor), Orkambi® (lumacaftor/ivacaftor) and Symkevi® (tezacaftor/ivacaftor), have substantially improved patients’ lives yet significantly burden healthcare budgets. This analysis aims to compare pricing and reimbursement of aforementioned cystic fibrosis medicines, across European countries.

Methods: Clinical trial registries, national databases, health technology assessment reports and grey literature of Austria, Belgium, Denmark, France, Germany, Ireland, Poland, Spain, Sweden, Switzerland, Netherlands, the United Kingdom were consulted. Publicly available prices, reimbursement statuses, economic evaluations, budget impact analyses and managed entry agreements of CFTR modulators were examined. Results: In Belgium, lowest list prices were observed for Kalydeco® (ivacaftor) and Symkevi® (tezacaftor/ivacaftor) at €417 per defined daily dose (DDD) and €372 per average daily dose (ADD), respectively. Whereas, Switzerland had the lowest price for Orkambi® (lumacaftor/ivacaftor) listed at €309 per DDD. Spain had the highest prices for Kalydeco® (ivacaftor) and Symkevi® (tezacaftor/ivacaftor) at €850 per DDD and €761 per ADD, whereas Orkambi® (lumacaftor/ivacaftor) was most expensive in Poland at €983 per DDD. However, list prices were subject to confidential discounts and likely varied from actual costs. In all countries, these treatments were deemed not to be cost-effective. The annual budget impact of the CFTR modulators varied between countries and depended on factors such as local product prices, size of target population, scope of costs and discounting. However, all modulators were fully reimbursed in ten of the evaluated countries except for Sweden and Poland that, respectively, granted reimbursement to one and none of the therapies. Managed entry agreements were confidential but commonly adopted to address financial uncertainties.

Conclusion: Discrepancies concerning prices, reimbursement and access were detected for Kalydeco® (ivacaftor), Orkambi® (lumacaftor/ivacaftor) and Symkevi® (tezacaftor/ivacaftor) across European countries.

Impulse oscillometry indices to detect an abnormal lung clearance index in childhood cystic fibrosis

The objective of our cross-sectional study was to assess the relationships between indices of multiple breath washout (MBW) and impulse oscillometry system (IOS) in cystic fibrosis in forty consecutive children (median age 8.1 years) in stable conditions and to evaluate whether cut-off values of IOS indices may help to avoid MBW, which is time-consuming. IOS measurements took a median duration of 3 min, while MBW measurements took a median duration of 49 min. Lung Clearance Index (LCI_2.5% ) depicted significant linear correlations with z-scores of R5Hz, R5-20Hz, X5Hz, AX, and Fres (r²  = 0.27 to 0.51). Receiver-operator characteristic curves were constructed and showed that the best compromise was obtained with the z-score of Fres, with a cut-off value of -1.37 that had a sensitivity of 0.966, a specificity of 0.636, and a negative predictive value of 0.875. This z-score is useful for excluding increased LCI_2.5% when below -1.37 using the reference set of Gochicoa et al. In conclusion, IOS measurement is easily and rapidly obtained in children and may be clinically useful for excluding increased LCI_2.5% , thus allowing the time-consuming MBW test to be avoided.

4-week daily airway clearance using oscillating positive-end expiratory pressure versus autogenic drainage in bronchiectasis patients: a randomised controlled trial

Background

Airway clearance is a fundamental component of bronchiectasis care. Lung clearance index (LCI) is a measurement of ventilation inhomogeneity. Its responsiveness to long-term airway clearance is unknown. We aimed to compare two methods of daily airway clearance over 4 weeks: autogenic drainage (AD) and oscillating positive airway pressure (oPEP), and to determine effects of airway clearance on LCI and clinical outcomes.

Methods

Adults with bronchiectasis naive to airway clearance were randomised to daily airway clearance with either AD or oPEP. Difference in LCI as primary outcome, spirometry, sputum volume and purulence, and quality of life were at randomisation and after 4 weeks of airway clearance.

Results

51 patients (32 women and 19 men, mean age 66.2±12.8 years) were randomised and 49 completed the study (25 AD and 24 oPEP). The LCI and forced expiratory volume in 1 s did not change between visits between groups (difference between groups 0.02), nor between visits in either group. Sputum quantity decreased in 12 out of 24 (50%) of the oPEP group, and in six out of 25 (24%) of the AD group (p=0.044). The “treatment burden” worsened or was unchanged in 70% of participants randomised to AD and 55% randomised to oPEP (p=0.038).

Conclusion

Sputum quantity decreased in more participants randomised to oPEP group after 1 month of daily airway clearance, with a better treatment burden. The effects of 4 weeks of airway clearance on LCI were not significant in either treatment group.

People with bronchiectasis were randomised to 4 weeks of two methods of daily airway clearance, autogenic drainage (AD) and oscillating PEP (oPEP). Sputum volume decreased in more people randomised to oPEP than AD. LCI did not change in either group.https://bit.ly/3gNj2bi

Inflammation biomarkers in sputum for clinical trials in cystic fibrosis: current understanding and gaps in knowledge

RATIONALE

Sputum biomarkers hold promise as a direct measure of inflammation within the cystic fibrosis (CF) lung, but variability in study design and sampling methodology have limited their use. A full evaluation of the reliability, validity and clinical relevance of individual biomarkers is required to optimise their use within CF clinical research.

OBJECTIVES

A biomarker Special Interest Working Group was established within the European Cystic Fibrosis Society-Clinical Trials Network Standardisation Committee, to perform a review of the evidence regarding sputum biomarkers in CF.

METHODS

From the 139 included articles, we identified 71 sputum biomarkers to undergo evaluation of their clinimetric properties, responsiveness, discriminant, concurrent and convergent validity.

RESULTS

Current evidence confirms the potential of sputum biomarkers as outcome measures in clinical trials. Inconsistency in responsiveness, concurrent and convergent validity require further research into these markers and processing standardisation before translation into wider use. Of the 71 biomarkers identified, Neutrophil Elastase (NE), IL-8, TNF-α and IL-1β, demonstrated validity and responsiveness to be currently considered for use in clinical trials. Other biomarkers show future promise, including IL-6, calprotectin, HMGB-1 and YKL-40.

CONCLUSION

A concerted international effort across the cystic fibrosis community is needed to promote high quality biomarker trial design, establish large population-based biomarker studies, and work together to create standards for collection, storage and analysis of sputum biomarkers.

Validation of a Spanish version of the Leicester Cough Questionnaire in cystic fibrosis

Cough is a main symptom in cystic fibrosis (CF). We aim to validate a Spanish version of the Leicester Cough Questionnaire (LCQ-Sp) to measure the impact of cough in CF bronchiectasis. A prospective longitudinal multicentre study was performed. Internal consistency and score changes over a 15-day period in stable state were assessed to analyse reliability. Concurrent validity was analysed by correlation with Saint George’s Respiratory Questionnaire (SGRQ) and convergent validity by assessing the association with clinical variables. Changes in scores between stable state and the first exacerbation were assessed to analyse responsiveness. 132 patients (29.73 ± 10.52 years) were enrolled in four hospitals. Internal consistency was high for the total score and good for the three domains (Cronbach’s α 0.81–0.93). The test–retest reliability showed an intraclass correlation coefficient of 0.86 for the total score. The correlation between LCQ-Sp and SGRQ scores was −0.74. The LCQ-Sp score negatively correlated with sputum volume, and the mean score decreased at the beginning of exacerbations (16.04±3.81 vs 13.91±4.29) with a large effect size. The LCQ-Sp is a reliable, repeatable and responsive instrument to assess the impact of cough in CF bronchiectasis and is responsive to change in the event of exacerbations.

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.

The short-term effects of ORKAMBI (lumacaftor/ivacaftor) on regional and distal lung structures using functional respiratory imaging

Background:

Lumacaftor/ivacaftor (LUM/IVA) has shown modest benefits in previous research, but the exact effects in the cystic fibrosis (CF) lung remain unclear. This study aims to offer novel information on the mode of action of the cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drug by assessing lung structure and function using functional respiratory imaging (FRI).

Methods:

CF patients aged ⩾12 years homozygous for F508del were recruited in an open-label study. Before and after 12 weeks of treatment with LUM/IVA, FRI was used to visualize regional information, such as air trapping, lobar volume and airway wall volume. Secondary outcomes included the CF-CT scoring system, spirometry, the Cystic Fibrosis Questionnaire–Revised (CFQ-R) questionnaire, exercise tolerance and nutritional status.

Results:

Of the 12 patients enrolled in the study, 11 completed all study visits. Concerning the FRI parameters, hyperinflation of the lung decreased, indicated by a reduction in air trapping and lobar volume at expiration. Also, a decrease in airway wall volume and a redistribution of pulmonary blood volume were noted, which might be related to a decrease in mucus impaction. Airway resistance, airway volume, internal airflow distribution and aerosol deposition pattern did not show significant changes. No significant improvements were found in any of the CF-CT scores or in the spirometric parameters. Other secondary outcomes showed similar results compared with previous research. Correlations at baseline were found between FRI and conventional outcomes, including physical functioning, spirometry and CF-CT scores.

Conclusions:

LUM/IVA decreased lung hyperinflation in combination with a potential decrease in mucus impaction, which can be related to an improved mucociliary transport. These results indicate that several FRI parameters, reflecting regional and distal lung structures, are more sensitive to changes caused by LUM/IVA than conventional respiratory outcomes.

New Insights in Microbial Species Predicting Lung Function Decline in CF: Lessons from the MucoFong Project

Several predictive models have been proposed to understand the microbial risk factors associated with cystic fibrosis (CF) progression. Very few have integrated fungal airways colonisation, which is increasingly recognized as a key player regarding CF progression. To assess the association between the percent predicted forced expiratory volume in 1 s (ppFEV1) change and the fungi or bacteria identified in the sputum, 299 CF patients from the “MucoFong” project were included and followed-up with over two years. The relationship between the microorganisms identified in the sputum and ppFEV1 course of patients was longitudinally analysed. An adjusted linear mixed model analysis was performed to evaluate the effect of a transient or chronic bacterial and/or fungal colonisation at inclusion on the ppFEV1 change over a two-year period. Pseudomonas aeruginosa, Achromobacter xylosoxidans, Stenotrophomonas maltophilia, and Candida albicans were associated with a significant ppFEV1 decrease. No significant association was found with other fungal colonisations. In addition, the ppFEV1 outcome in our model was 11.26% lower in patients presenting with a transient colonisation with non-pneumoniae Streptococcus species compared to other patients. These results confirm recently published data and provide new insights into bacterial and fungal colonisation as key factors for the assessment of lung function decline in CF patients.

Effects of Lumacaftor-Ivacaftor on Lung Clearance Index, Magnetic Resonance Imaging, and Airway Microbiome in Phe508del Homozygous Patients with Cystic Fibrosis

Rationale: Previous studies showed that lumacaftor-ivacaftor therapy results in partial rescue of CFTR (cystic fibrosis [CF] transmembrane conductance regulator) activity and a moderate improvement of spirometry in Phe508del homozygous patients with CF. However, the effects of lumacaftor-ivacaftor on lung clearance index (LCI), lung morphology and perfusion detected by chest magnetic resonance imaging (MRI), and effects on the airway microbiome and inflammation remain unknown. Objectives: To investigate the effects of lumacaftor-ivacaftor on LCI, lung MRI scores, and airway microbiome and inflammation. Methods: In this prospective observational study we assessed clinical outcomes including spirometry and body mass index, LCI, lung MRI scores, sputum microbiome, and proinflammatory cytokines in 30 Phe508del homozygous patients with CF 12 years and older before and 8-16 weeks after initiation of lumacaftor-ivacaftor therapy. Results: Lumacaftor-ivacaftor had no effects on forced expiratory volume in 1 second (FEV₁% predicted) (1.7%; 95% confidence interval [CI], -1.0% to 4.3%; P = 0.211) but improved LCI (-1.6; 95% CI, -2.6 to -0.5; P < 0.01) and MRI morphology (-1.3; 95% CI, -2.3 to -0.3; P < 0.05) and perfusion score (-1.2; 95% CI, -2.3 to -0.2; P < 0.05) in our study cohort. Furthermore, lumacaftor-ivacaftor decreased the total bacterial load (-1.8; 95% CI, -3.3 to -0.34; P < 0.05) and increased the Shannon diversity of the airway microbiome (0.4; 95% CI, 0.1 to 0.8; P < 0.05), and reduced IL-1β (interleukin-1β) concentration (median change, -324.2 pg/ml; 95% CI, -938.7 to 290.4 pg/ml; P < 0.05) in sputum of Phe508del homozygous patients. Conclusions: This study shows that lumacaftor-ivacaftor has beneficial effects on lung ventilation, morphology, and perfusion, as well as on the airway microbiome and inflammation in Phe508del homozygous patients. Our results suggest that LCI and MRI may be more sensitive than FEV₁% predicted to detect response to CFTR modulator therapy in patients with chronic CF lung disease. Clinical trial registered with ClinicalTrials.gov (NCT02807415).

Correction of sensor crosstalk error in Exhalyzer D multiple-breath washout device significantly impacts outcomes in children with cystic fibrosis

RATIONALE

Nitrogen multiple-breath washout is an established technique to assess functional residual capacity and ventilation inhomogeneity in the lung. Accurate measurement of gas concentrations is essential for the appropriate calculation of clinical outcomes.

OBJECTIVES

We investigated the accuracy of oxygen and carbon dioxide gas sensor measurements used for the indirect calculation of nitrogen concentration in a commercial multiple-breath washout device (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) and its impact on functional residual capacity and lung clearance index.

METHODS

High precision calibration gas mixtures and mass spectrometry were used to evaluate sensor output. We assessed the impact of corrected signal processing on multiple-breath washout outcomes in a dataset of healthy children and children with cystic fibrosis using custom analysis software.

RESULTS

We found inadequate correction for the cross sensitivity of the oxygen and carbon dioxide sensors in the Exhalyzer D device. This results in an overestimation of expired nitrogen concentration, and consequently multiple-breath washout outcomes. Breath-by-breath correction of this error reduced the mean (SD) cumulative expired volume by 19.6 (5.0)%, functional residual capacity by 8.9 (2.2)%, and lung clearance index by 11.9 (4.0)%. It also substantially reduced the level of the tissue nitrogen signal at the end of measurements.

CONCLUSIONS

Inadequate correction for cross sensitivity in the oxygen and carbon dioxide gas sensors of the Exhalyzer D device leads to an overestimation of functional residual capacity and lung clearance index. Correction of this error is possible and could be applied by re-analyzing the measurements in an updated software version.

The Association between IgG and Disease Severity Parameters in CF Patients

Assessing disease severity in patients with cystic fibrosis (CF) is essential when directing therapies. Serum immunoglobulin G (IgG) levels increase with disease severity. Lung clearance index (LCI) is recognized as an outcome measure for CF clinical trials. Our aim was to evaluate the correlations between IgG and disease severity markers. This was a single-center retrospective study, evaluating association between IgG and markers of severity in CF patients (including clinical characteristics, lung spirometry, LCI, clinical scores and computed tomography (CT) scores) during stable conditions. There were 69 patients, age 20.5 ± 11.6 years. Nineteen (27.5%) patients had elevated IgG. IgG correlated positively with LCI (r = 0.342, p = 0.005). IgG was higher in pancreatic insufficient (PI) and patients with liver disease (1504.3 ± 625.5 vs. 1229 ± 276.1 mg/dL in PI vs. PS, p = 0.023, and 1702.6 ± 720.3 vs. 1256.2 ± 345.5 mg/dL with vs. without liver disease, p = 0.001, respectively). IgG also correlated positively with CRP, CT score, and days with antibiotics in the previous year (r = 0.38, p = 0.003; r = 0.435, p = 0.001; and r = 0.361, p = 0.002, respectively), and negatively with FEV1% and SK score (r = −0.527, p < 0.001 and r = −0.613, p < 0.001, respectively). IgG correlated with clinical parameters, pulmonary functions, and imaging. However, this is still an auxiliary test, complementing other tests, including lung function and imaging tests. Larger multi-center longitudinal studies are warranted.

Association of lung clearance index with survival in individuals with cystic fibrosis

BACKGROUND

The lung clearance index (LCI) assesses global ventilation inhomogeneity and is a sensitive biomarker of airway function in cystic fibrosis (CF) lung disease.

OBJECTIVES

We examined the association of LCI with the risk of death or lung transplantation (LTX) in individuals with CF.

METHODS

We performed a retrospective analysis in a cohort of individuals with CF aged≥5 years with LCI and FEV₁ measurements performed between 1980 and 2006. The outcome was time until death or LTX. We used the earliest available LCI and FEV₁ values in a Cox proportional hazard regression adjusted for demographic and clinical variables. For sensitivity analyses, we used the mean of the first three LCI and FEV₁ measurements, stratified the cohort based on age, and investigated individuals with normal FEV₁.

RESULTS

In total, 237 individuals with CF with a mean (range) age of 13.9 (5.6-41.0) years were included. The time-to-event analysis accrued 3813 person-years and 94 (40%) individuals died or received LTX. Crude hazard ratios [95% CI] were 1.04 [1.01-1.06] per one z-score increase in LCI and 1.25 [1.11-1.41] per one z-score decrease in FEV₁. After adjusting LCI and FEV₁ mutually in addition to sex, age, BMI and the number of hospitalisations, hazard ratios were 1.04 [1.01-1.07] for LCI, and 1.12 [0.95-1.33] for FEV₁. Sensitivity analyses yielded similar results and using the mean LCI strengthened the associations.

CONCLUSIONS

Increased ventilation inhomogeneity is associated with greater risk of death or LTX. Our data support LCI as novel surrogate of survival in individuals with CF.

A Short extension to multiple breath washout provides additional signal of distal airway disease in people with CF: A pilot study

BACKGROUND

Adding a slow vital capacity (SVC) to multiple breath washout (MBW) allows quantification of otherwise overlooked signal from under/un-ventilated lung units (UVLU) and may provide a more comprehensive assessment of airway disease than conventional lung clearance index (LCI_2.5).

METHODS

We conducted a pilot study on people undergoing MBW tests: 10 healthy controls (HC) and 43 cystic fibrosis (CF) subjects performed an SVC after the standard end of test. We term the new outcome LCI with Short extension (LCI_ShX). We assessed (i) CF/ HC differences, (ii) variability (iii) effect of pulmonary exacerbation (PEx)/treatment and (iv) relationship with CF computed tomography (CFCT) scores.

RESULTS

HC/ CF group differences were larger with LCI_ShX than LCI_2.5 (P<0.001). Within the CF group UVLU was highly variable and when abnormal it did not correlate with corresponding LCI_2.5. Signal showed little variability during clinical stability (n = 11 CF; 2 visits; median inter-test variability 2.6% LCI_ShX, 2.5% LCI_2.5). PEx signal was significantly greater for LCI_ShX both for onset and resolution. Both MBW parameters correlated significantly with total lung CT scores and hyperinflation but only LCI_ShX correlated with mucus plugging.

CONCLUSIONS

UVLU captured within the LCI_ShX varies between individuals; the lack of relationship with LCI_2.5 demonstrates that new, additional information is being captured. LCI_ShX repeatability during clinical stability combined with its larger signal around episodes of PEx may lend it superior sensitivity as an outcome measure. Further studies will build on this pilot data to fully establish its utility in monitoring disease status.

Seven Pillars of Small Airways Disease in Asthma and COPD: Supporting Opportunities for Novel Therapies

Identification of pathologic changes in early and mild obstructive lung disease has shown the importance of the small airways and their contribution to symptoms. Indeed, significant small airways dysfunction has been found prior to any overt airway obstruction being detectable by conventional spirometry techniques. However, most therapies for the treatment of obstructive lung disease target the physiological changes and associated symptoms that result from chronic lung disease, rather than directly targeting the specific underlying causes of airflow disruption or the drivers of disease progression. In addition, although spirometry is the current standard for diagnosis and monitoring of response to therapy, the most widely used measure, FEV1 , does not align with the pathologic changes in early or mild disease and may not align with symptoms or exacerbation frequency in the individual patient. Newer functional and imaging techniques allow more effective assessment of small airways dysfunction; however, significant gaps in our understanding remain. Improving our knowledge of the role of small airways dysfunction in early disease in the airways, along with the identification of novel end points to measure subclinical changes in this region (ie, those not captured as symptoms or identified through standard FEV1), may lead to the development of novel therapies that directly combat early airways disease processes with a view to slowing disease progression and reversing damage. This expert opinion paper discusses small airways disease in the context of asthma and COPD and highlights gaps in current knowledge that impede earlier identification of obstructive lung disease and the development and standardization of novel small airways-specific end points for use in clinical trials.

The measurement properties of tests and tools used in cystic fibrosis studies: a systematic review

There is no consensus on how best to measure responses to interventions among children and adults with cystic fibrosis (CF). We have systematically reviewed and summarised the characteristics and measurement properties of tests and tools that have been used to capture outcomes in studies among people with CF, including their reliability, validity and responsiveness. This review is intended to guide researchers when selecting tests or tools for measuring treatment effects in CF trials. A consensus set of these tests and tools could improve consistency in how outcomes are captured and thereby facilitate comparisons and synthesis of evidence across studies.

Real-world assessment of LCI following lumacaftor-ivacaftor initiation in adolescents and adults with cystic fibrosis

Lung clearance index (LCI) is a biomarker of ventilation inhomogeneity. Data are scarce on its usefulness in daily practice for monitoring the effects of treatments in older children and adults with CF. In this French observational study of lumacaftor-ivacaftor, 63 of 845 patients (7.5%) had available LCI performed at baseline and at six (M6; n=34) or 12 months (M12; n=46) after lumacaftor-ivacaftor initiation. At inclusion, median [IQR] age was 16 years [13-17], ppFEV₁ was 72.8 [59.6-80.7], and LCI was 12.3 [10.3-15.0]. At both M6 and M12, no statistically significant LCI increases of 0.13 units or 1.34% (95% CI: -4.85-7.53) and 0.6 units or 6.66% (95% CI: -0.03-13.5) were observed. Discordant results between LCI and ppFEV₁ were observed in one-third of the patients. In daily practice, LCI monitoring in adolescents and young adults with moderate lung disease gives results that are more heterogenous than those reported in children with milder disease.

Time to get serious about the detection and monitoring of early lung disease in cystic fibrosis

Structural and functional defects within the lungs of children with cystic fibrosis (CF) are detectable soon after birth and progress throughout preschool years often without overt clinical signs or symptoms. By school age, most children have structural changes such as bronchiectasis or gas trapping/hypoperfusion and lung function abnormalities that persist into later life. Despite improved survival, gains in forced expiratory volume in one second (FEV₁) achieved across successive birth cohorts during childhood have plateaued, and rates of FEV₁ decline in adolescence and adulthood have not slowed. This suggests that interventions aimed at preventing lung disease should be targeted to mild disease and commence in early life. Spirometry-based classifications of 'normal' (FEV₁≥90% predicted) and 'mild lung disease' (FEV₁ 70%-89% predicted) are inappropriate, given the failure of spirometry to detect significant structural or functional abnormalities shown by more sensitive imaging and lung function techniques. The state and readiness of two imaging (CT and MRI) and two functional (multiple breath washout and oscillometry) tools for the detection and monitoring of early lung disease in children and adults with CF are discussed in this article.Prospective research programmes and technological advances in these techniques mean that well-designed interventional trials in early lung disease, particularly in young children and infants, are possible. Age appropriate, randomised controlled trials are critical to determine the safety, efficacy and best use of new therapies in young children. Regulatory bodies continue to approve medications in young children based on safety data alone and extrapolation of efficacy results from older age groups. Harnessing the complementary information from structural and functional tools, with measures of inflammation and infection, will significantly advance our understanding of early CF lung disease pathophysiology and responses to therapy. Defining clinical utility for these novel techniques will require effective collaboration across multiple disciplines to address important remaining research questions. Future impact on existing management burden for patients with CF and their family must be considered, assessed and minimised.To address the possible role of these techniques in early lung disease, a meeting of international leaders and experts in the field was convened in August 2019 at the Australiasian Cystic Fibrosis Conference. The meeting entitiled 'Shaping imaging and functional testing for early disease detection of lung disease in Cystic Fibrosis', was attended by representatives across the range of disciplines involved in modern CF care. This document summarises the proceedings, key priorities and important research questions highlighted.

Psychometrics of HRQoL questionnaires in bronchiectasis: A systematic review and meta-analysis

Introduction

Understanding the psychometric properties of health-related quality of life (HRQoL) questionnaires can help inform selection in clinical trials. Our objective was to assess the psychometric properties of HRQoL questionnaires in bronchiectasis using a systematic review and meta-analysis of the literature.

Methods

A literature search was conducted. HRQoL questionnaires were assessed for psychometric properties (reliability, validity, minimal clinically important difference (MCID) and floor/ceiling effects). Meta-analyses assessed the associations of HRQoL with clinical measures and responsiveness of HRQoL in clinical trials.

Results

166 studies and 12 HRQoL questionnaires were included. The Bronchiectasis Health Questionnaire (BHQ), Leicester Cough Questionnaire (LCQ), Chronic Obstructive Pulmonary Disease (COPD) Assessment Test (CAT) and Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) had good internal consistency in all domains reported (Cronbach's α≥0.7) across all studies, and the Quality of Life-Bronchiectasis (QOL-B), St George's Respiratory Questionnaire (SGRQ), Chronic Respiratory Disease Questionnaire (CRDQ) and Seattle Obstructive Lung Disease Questionnaire (SOLQ) had good internal consistency in all domains in the majority of (but not all) studies. BHQ, SGRQ, LCQ and CAT had good test–retest reliability in all domains reported (intraclass correlation coefficient ≥0.7) across all studies, and QOL-B, CRDQ and SOLQ had good test–retest reliability in all domains in the majority of (but not all) studies. HRQoL questionnaires were able to discriminate between demographics, important markers of clinical status, disease severity, exacerbations and bacteriology. For HRQoL responsiveness, there was a difference between the treatment and placebo effect.

Conclusions

SGRQ was the most widely used HRQoL questionnaire in bronchiectasis studies and it had good psychometric properties; however, good psychometric data are emerging on the bronchiectasis-specific HRQoL questionnaires QOL-B and BHQ. Future studies should focus on the medium- to long-term test–retest reliability, responsiveness and MCID in these HRQoL questionnaires which show potential in bronchiectasis.

The psychometric properties of health-related quality of life questionnaires should inform the selection of patient-reported outcomes in bronchiectasis clinical trialshttps://bit.ly/3wQuSrm

A multimodal approach to detect and monitor early lung disease in cystic fibrosis

Introduction: In the early stages, lung involvement in cystic fibrosis (CF) can be silent, with disease progression occurring in the absence of clinical symptoms. Irreversible airway damage is present in the early stages of disease; however, reliable biomarkers of early damage due to inflammation and infection that are universally applicable in day-to-day patient management have yet to be identified.Areas covered: At present, the main methods of detecting and monitoring early lung disease in CF are the lung clearance index (LCI), computed tomography (CT), and magnetic resonance imaging (MRI). LCI can be used to detect patients who may require more intense monitoring, identify exacerbations, and monitor responses to new interventions. High-resolution CT detects structural alterations in the lungs of CF patients with the best resolution of current imaging techniques. MRI is a radiation-free imaging alternative that provides both morphological and functional information. The role of MRI for short-term follow-up and pulmonary exacerbations is currently being investigated.Expert opinion: The roles of LCI and MRI are expected to expand considerably over the next few years. Meanwhile, closer collaboration between pulmonology and radiology specialties is an important goal toward improving care and optimizing outcomes in young patients with CF.

An observational study of anaerobic bacteria in cystic fibrosis lung using culture dependant and independent approaches

Strict anaerobes are undeniably important residents of the cystic fibrosis (CF) lung but are still unknowns. The main objectives of this study were to describe anaerobic bacteria diversity in CF airway microbiota and to evaluate the association with lung function. An observational study was conducted during eight months. A hundred and one patients were enrolled in the study, and 150 sputum samples were collected using a sterile sample kit designed to preserve anaerobic conditions. An extended-culture approach on 112 sputa and a molecular approach (quantitative PCR targeting three of the main anaerobic genera in CF lung: Prevotella, Veillonella, and Fusobacterium) on 141 sputa were developed. On culture, 91.1% of sputa were positive for at least one anaerobic bacterial species, with an average of six anaerobic species detected per sputum. Thirty-one anaerobic genera and 69 species were found, which is the largest anaerobe diversity ever reported in CF lungs. Better lung function (defined as Forced Expiratory Volume in one second > 70%) was significantly associated with higher quantification of Veillonella. These results raise the question of the potential impact of anaerobes on lung function.

Withdrawal of dornase alfa increases ventilation inhomogeneity in children with cystic fibrosis

BACKGROUND

The lung clearance index (LCI) is increasingly used as an outcome in clinical trials of patients with mild cystic fibrosis (CF) lung disease. Yet, understanding the impact of standard CF respiratory therapy on LCI is needed. We assessed to what degree withdrawal of nebulised dornase alfa affected LCI in school-age children with CF not receiving CFTR modulators or hydrator therapy.

METHODS

A single-centre, randomised, controlled, parallel group study to determine effects of one month's withdrawal of nebulised dornase alfa (intervention) in 5-18 years old children with CF. Remaining chronic maintenance therapy stayed unchanged. Outcome measures were assessed at two visits one month apart. Primary outcome was absolute change in LCI. Secondary outcomes were FEV₁, FEF_25-75 and CF Questionnaire-revised (CFQ-R) respiratory symptom score. Possible harmful effects were assessed by comparing the occurrence of pulmonary exacerbations between groups.

RESULTS

Twenty-eight children (median age 10.4 [interquartile range: 7.6; 13.5] years) with CF received standard care (n = 14) or intervention (n = 14). Compared with the control group, LCI increased (worsened) 1.74 (95% confidence interval: 0.62; 2.86) during withdrawal of dornase alfa, while FEV₁ (-6.8% predicted) and FEF_25-75 (-13.1% predicted) decreased significantly. Change in CFQ-R respiratory symptom score and the occurrence of pulmonary exacerbations did not differ significantly between groups.

CONCLUSIONS

One month's withdrawal of dornase alfa caused increasing ventilation inhomogeneity and deteriorating FEV₁ and FEF_25-75 in school-age children with mild CF. Hence, adherence to dornase alfa optimally needs to be addressed when using LCI and spirometric parameters as endpoints, even in short-term clinical trials.

The remaining barriers to normalcy in CF: Advances in assessment of CF lung disease

Despite early diagnosis of cystic fibrosis (CF) through newborn screening, a substantial proportion of infants and young children with CF still demonstrate physiologic and structural evidence of lung disease progression, such as obstructive airway disease and bronchiectasis. The growing availability of highly effective CF transmembrane conductance regulatory modulator therapy to the vast majority of people with CF has led to the potential to alter the natural history of CF lung disease, but to assess the full impact of these therapies on CF lung disease and to help guide treatment, sensitive measures of early and mild disease are needed. Chest imaging using computed tomography or magnetic resonance imaging is one approach, but technologic barriers and/or concern about exposure to ionizing radiation may limit its use. However, advances in physiologic measurement techniques and exhaled breath analysis offer another option for assessment of CF lung disease.

Abnormal glucose tolerance and lung function in children with cystic fibrosis. Comparing oral glucose tolerance test and continuous glucose monitoring

BACKGROUND

Cystic fibrosis (CF) related diabetes (CFRD) is a common complication of CF. CFRD is associated with declining lung function even before its onset. Regular screening for CFRD using oral glucose tolerance test (OGTT) is recommended. Additionally, continuous glucose monitoring (CGM) has surfaced as a possible surveillance method, but evidence for its use and concordance with OGTT has not been established.

METHODS

Children were prospectively recruited at CF center Lund to undergo both intermittent scan CGM (isCGM) and OGTT. Lung function was evaluated by spirometry and multiple breath washout. Demographic and clinical data were collected from the Swedish national CF registry.

RESULTS

32 patients participated in the study, yielding 28 pairs of isCGMs and OGTTs. The OGTTs showed that two patients met the criteria of CFRD, seven had impaired glucose tolerance (IGT) and indeterminate glycemia (INDET) was found in eleven cases. The isCGM percent of measurements >8mmol/L and the number of peaks per day >11 mmol/L have correlations with intermediate OGTT glucose time points, but not the 2hour glucose value. Patients with abnormal glucose tolerance (AGT) had lower lung function than those with normal glucose tolerance demonstrated by both FEV1% predicted and lung clearance index (LCI).

CONCLUSION

Correlations can be found between isCGM and OGTT in regards to the latter's intermediate time points. LCI demonstrates as well as FEV1% of predicted, worse lung function in children and adolescents with abnormal glucose tolerance in CF.

Toward the Establishment of New Clinical Endpoints for Cystic Fibrosis: The Role of Lung Clearance Index and Cardiopulmonary Exercise Testing

As Cystic Fibrosis (CF) treatment advances, research evidence has highlighted the value and applicability of Lung Clearance Index and Cardiopulmonary Exercise Testing as endpoints for clinical trials. In the context of these new endpoints for CF trials, we have explored the use of these two test outcomes for routine CF care. In this review we have presented the use of these methods in assessing disease severity, disease progression, and the efficacy of new interventions with considerations for future research.

Multiple breath washout quality control in the clinical setting

BACKGROUND

Multiple breath washout (MBW) is increasingly used in the clinical assessment of patients with cystic fibrosis (CF). Guidelines for MBW quality control (QC) were developed primarily for retrospective assessment and central overreading. We assessed whether real-time QC of MBW data during the measurement improves test acceptability in the clinical setting.

METHODS

We implemented standardized real-time QC and reporting of MBW data at the time of the measurement in the clinical pediatric lung function laboratory in Bern, Switzerland, in children with CF aged 4-18 years. We assessed MBW test acceptability before (31 tests; 89 trials) and after (32 tests; 96 trials) implementation of real-time QC and compared agreement between reviewers. Further, we assessed the implementation of real-time QC at a secondary center in Zurich, Switzerland.

RESULTS

Before the implementation of real-time QC in Bern, only 58% of clinical MBW tests were deemed acceptable following retrospective QC by an experienced reviewer. After the implementation of real-time QC, MBW test acceptability improved to 75% in Bern. In Zurich, after the implementation of real-time QC, test acceptability improved from 38% to 70%. Further, the agreement between MBW operators and an experienced reviewer for test acceptability was 84% in Bern and 93% in Zurich.

CONCLUSION

Real-time QC of MBW data at the time of measurement is feasible in the clinical setting and results in improved test acceptability.

ENaC inhibition in cystic fibrosis: potential role in the new era of CFTR modulator therapies

Small-molecule cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs for cystic fibrosis are the first therapies since the disease was initially described by Fanconiet al. [1] in 1936 to target and partially restore the function of the CFTR Cl⁻ channel. CFTR modulator therapy is expected to have significant clinical benefits for many, but it does not result in a cure and is not appropriate or available for all patients with cystic fibrosis [2, 3]. In this review, evidence is described suggesting that inhibiting the epithelial Na⁺ channel (ENaC) responsible for the Na⁺/fluid absorption that contributes to airway surface dehydration and impaired mucociliary clearance (MCC) observed in cystic fibrosis airways may significantly improve clinical outcomes irrespective of the CFTR genotype, and may synergise with currently approved CFTR modulators to further improve clinical outcomes.

ENaC inhibition with BI 1265162 is a promising strategy to optimise outcomes in patients with CF either eligible, or ineligible, for CFTR modulator therapy. Phase II clinical trials of BI 1265162 must now show this translates into clinical benefit.https://bit.ly/2OQ1IUI

Lung function deterioration in school children with cystic fibrosis

INTRODUCTION

Lung disease in cystic fibrosis (CF) begins early in life but the capabilities for detecting abnormalities of pulmonary dysfunction in children remain limited.

OBJECTIVE

The study aimed to evaluate the early progression of lung function by the analysis of pulmonary hyperinflation, ventilation inhomogeneity (VI), trapped gas and airway obstruction with age.

METHODS

One hundred CF children aged 7 to 18, divided into two groups aged 7 to 12 (n = 40) and 13 to 18 (n = 60), were enrolled. Patients performed multiple-breath nitrogen washout (MBNW) tests and plethysmography for measurements of lung clearance index (LCI), functional residual capacity (FRC_pleth , FRC_MBNW ), volume of trapped gas (V_T ), total resistance, and effective and specific effective airway resistance (R_eff , sR_eff ).

RESULTS

We obtained a positive correlation of FRC_pleth , FRC_MBNW , and LCI with age. A linear correlation between FRC_MBNW and FRC_pleth (P < .0001) was observed. VI was higher in the group of older patients (9.79 in the group aged 7-12 and 11.67 in the group aged 13-18). An increased effective specific airway resistance >2 (z-score) was present in 58% of all subjects (50% and 63.3%, respectively). Pulmonary hyperinflation (FRC_pleth >2 z-score) was observed in 33% of all patients: 25% and 36.6%, respectively. Trapped gas (V_T  > 2 z-score) was present in 18% of all children: 30% and 10%, respectively.

CONCLUSION

A gradual decline in lung function is associated with an increase in VI, airway obstruction, pulmonary hyperinflation and development of trapped gas. In children who cannot perform either spirometry or plethysmography, MBNW can deliver a measurement of LCI connecting with VI as well as FRC_MBNW to indicate indirectly the increase of hyperinflation.

Designing Clinical Trials for Anti-Inflammatory Therapies in Cystic Fibrosis

The inflammatory response in the CF airway begins early in the disease process and becomes persistent through life in most patients. Inflammation, which is predominantly neutrophilic, worsens airway obstruction and plays a critical role in the development of structural lung damage. While cystic fibrosis transmembrane regulator modulators will likely have a dramatic impact on the trajectory of CF lung disease over the coming years, addressing other important aspects of lung disease such as inflammation will nevertheless remain a priority. Considering the central role of neutrophils and their products in the inflammatory response, potential therapies should ultimately affect neutrophils and their products. The ideal anti-inflammatory therapy would exert a dual effect on the pro-inflammatory and pro-resolution arms of the inflammatory cascade, both of which contribute to dysregulated inflammation in CF. This review outlines the key factors to be considered in the design of clinical trials evaluating anti-inflammatory therapies in CF. Important lessons have been learned from previous clinical trials in this area and choosing the right efficacy endpoints is key to the success of any anti-inflammatory drug development program. Identifying and validating non-invasive biomarkers, novel imaging techniques and sensitive lung function tests capable of monitoring disease activity and therapeutic response are important areas of research and will be useful for the design of future anti-inflammatory drug trials.

Investigating outcome measures for assessing airway clearance techniques in adults with cystic fibrosis: protocol of a single-centre randomised controlled crossover trial

Introduction

Airway clearance techniques (ACTs) are a gold standard of cystic fibrosis management; however, the majority of research evidence for their efficacy is of low standard; often attributed to the lack of sensitivity from outcome measures (OMs) used historically. This randomised controlled trial (RCT) investigates these standard OMs (sputum weight, forced expiratory volume in 1 s) and new OMs (electrical impedance tomography (EIT), multiple breath washout (MBW) and impulse oscillometry (IOS)) to determine the most useful measures of ACT.

Methods and analysis

This is a single-centre RCT with crossover design. Participants perform MBW, IOS and spirometry, and then are randomised to either rest or supervised ACT lasting 30–60 min. MBW, IOS and spirometry are repeated immediately afterwards. EIT and sputum are collected during rest/ACT. On a separate day, the OMs are performed with the other intervention. Primary endpoint is difference in change in OMs before and after ACT/rest. Sample size was calculated with 80% power and significance of 5% for each OM (target n=64).

Ethics and dissemination

Ethics approval was gained from the London–Chelsea Research Ethics Committee (reference 16/LO/0995, project ID 154635). Dissemination will involve scientific conference presentation and publication in a peer-reviewed journal.

Trial registration numbers

ISRCTN11220163 and NCT02721498.

An innovative phase II trial to establish proof of efficacy and optimal dose of a new inhaled epithelial sodium channel inhibitor BI 1265162 in adults and adolescents with cystic fibrosis: BALANCE-CFTM 1

Inhibition of the epithelial sodium channel (ENaC) represents an important, mutation-agnostic therapeutic approach to restore airway surface liquid in patients with cystic fibrosis (CF). A phase II trial of the ENaC inhibitor BI 1265162, inhaled via the Respimat® Soft Mist™ inhaler, in patients aged ≥12 years with CF is being conducted to assess the efficacy and safety of BI 1265162, on top of standard CF treatment (www.clinicaltrials.gov identifier NCT04059094). BALANCE-CF™ 1 is a multinational, randomised, double-blind, placebo-controlled, parallel-group, dose-ranging trial consisting of 2 weeks' screening, 4 weeks' randomised treatment and 1 week follow-up. 98 patients, including ≥21 adolescents, will be randomised. First, 28 patients will be allocated to the highest dose of BI 1265162 (200 µg twice daily) or placebo in a 1:1 ratio. The remaining 70 patients will be allocated to one of five treatment arms (200 µg, 100 µg, 50 µg, 20 µg or placebo twice daily), with a final distribution ratio of 2:1:1:1:2. Recruitment and randomisation will begin with adult patients. An independent data monitoring committee will review safety data to advise on inclusion of adolescents and study continuation. A futility analysis will be conducted after 28 patients to prevent exposure of further patients in case of insufficient evidence of clinical efficacy. The design ensures that potential for effect is assessed ahead of wider enrolment, allowing investigation of a dose-response effect with minimal patient numbers. The results will increase understanding of efficacy, safety and optimal dosing of the inhaled ENaC inhibitor BI 1265162 in adults and adolescents with CF.