Is Obesity a Problem in New Cystic Fibrosis Treatments?

INTRODUCTION: Malnutrition has always been a problem in CF (cystic fibrosis) patients; however, new treatments with CFTR (cystic fibrosis transmembrane conductance regulator protein) modulators have led to weight gain, with some patients at risk of overweight and obesity. OBJECTIVE: Our study aimed to analyze the evolution of BMI (body mass index) after one year of treatment with triple therapy and the factors associated with weight gain in CF patients undergoing treatment with triple therapy with CFTR protein modulators (ETI) (elexacaftor/tezacaftor/ivacaftor). METHODS: We conducted a prospective, observational, longitudinal, multicenter study in patients diagnosed with cystic fibrosis, aged 18 years or older, with at least one F508del allele and who underwent ETI therapy for at least one year, from 2020 to 2023. One hundred and eight patients from two cystic fibrosis units in Spain, Princess University Hospital of Madrid (74 patients) and Central University Hospital of Asturias (HUCA) (34 patients), were included. Demographic data, anthropometric data, lung function, and exacerbations were collected, comparing the data in the previous year to the start of therapy with the results after one year of treatment. Multivariant models were developed to account for repeated weight and BMI measurements, using a mixed effects model approach and accounting for possible modifying factors Results: One hundred and eight patients were included in the study, 58 men (53.7%) and 50 women (46.3%) with a mean age of 29.5 ± 9.4 years (18-59). Patient weight and BMI were recorded at baseline and at 3-month intervals during the study period. The weight increased from 59.6 kg to 62.6 kg and BMI increased from 21.9 kg/m2 to 23.0 kg/m2 after one year of treatment (p < 0.0001 for both). The proportion of underweight individuals decreased after one year of ETI therapy, from 9.3% to 1.9%, while the proportion of overweight or obese individuals increased from 8.3% to 22.9 % at the same time (p < 0.001). In relation to exacerbations, there is a significant increase in the number of patients who did not have any exacerbations after one year of treatment, which increased from 10.2% to 46.2% (p < 0.001), while the number of patients who had >4 exacerbations decreased significantly, from 40.7% to 1.9% (p < 0.001). FEV1% (forced expiratory volume) increased from 63.9 ± 20.9 to 76.8 ± 21.4 (p < 0.001) and the VR/TLC (residual volume/total lung capacity) value decreased from 45.1 ± 10.9 to 34.9 ± 6.2 (p < 0.001). The proportion with FEV1% > 80% increased from 23.1% before ETI therapy to 49.1% one year after ETI therapy. We performed multivariate mixed models to evaluate the evolution of BMI changes with time, accounting for repeated measures and for possible modifying factors. After the introduction of the triple therapy, patients included in the study had significant weight gain during the 12 months, and when including different covariates in the multivariate mixed model, we found that lower baseline BMI, lower baseline FEV1 and FVC (forced vital capacity), and higher VR/TLC value and higher number of exacerbations were associated with higher BMI changes over the study period. CONCLUSIONS: CF patients treated with triple therapy experience significant weight gain, increasing the proportion of overweight patients. CF patients who experienced greater weight gain were those with worse BMI at the start of treatment, as well as patients with worse lung function and a greater number of exacerbations in the year before starting ETI therapy.

Assessment of respiratory mechanics and X-ray velocimetry functional imaging in two cystic fibrosis rat models.

Two cystic fibrosis (CF) rat models, one carrying the common Phe508del mutation and the other a nonsense cystic fibrosis transmembrane conductance regulator (CFTR) mutation (knockout) were previously characterised. Although relevant CFTR mRNA reductions were present in the lung, no overt CF lung disease was observed. This study used flexiVent lung mechanic assessment and regional ventilation assessment via X-ray velocimetry (XV) functional imaging to assess the lung phenotype in both models. To determine the sensitivity of XV regional ventilation imaging, the effect of a localised physical obstruction (delivery of agar beads to part of the lungs) on lung ventilation was examined. At baseline, Phe508del and knockout CF rats had a lower inspiratory capacity, total respiratory system compliance, and static compliance than wildtype rats. Following agar bead delivery all XV ventilation parameters were altered, with substantial increases in poorly ventilated regions and ventilation heterogeneity. XV ventilation maps accurately identified locations of bead-induced airflow changes. Despite unremarkable lung histopathology, this study indicated that CF rats display altered respiratory mechanics, with CF rats needing to exert additional effort to expand and deflate their lungs due to increased stiffness. This study demonstrated the utility of XV imaging providing spatial lung ventilation information.

Clinical applications of forced oscillation technique (FOT) for diagnosis and management of obstructive lung diseases in children.

Obstructive lung diseases such as bronchial asthma, COPD, and cystic fibrosis are a burden on many patients across the globe. Spirometry is considered the gold standard for diagnosing airflow obstruction, but it can be difficult for pediatric patients to do and requires a lot of effort. As a result, healthcare providers need new, effortless methods to diagnose airway obstructions, particularly in young children and individuals unable to perform the spirometry maneuver. The forced oscillation technique is a modern method requiring only tidal breathing combined with the application of external, source of low-amplitude oscillations to evaluate the respiratory system's response. It might be essential for identifying early respiratory changes caused by smoking, childhood asthma, and may prove more sensitive than spirometry in identifying peripheral airway disturbances or evaluating the long-term success of therapy. This review describes the methodology and the indications for the forced oscillation technique and outlines its relevance in clinical practice.

New drugs, new challenges in cystic fibrosis care.

Cystic fibrosis (CF) is a genetic disease caused by variants in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein, a chloride and bicarbonate channel. CFTR dysfunction results in a multiorgan disease with the main clinical features being exocrine pancreatic insufficiency and diffuse bronchiectasis with chronic airway infection leading to respiratory failure and premature death. Over the past decades, major progress has been made by implementing multidisciplinary care, including nutritional support, airway clearance techniques and antibiotics in specialised CF centres. The past decade has further seen the progressive development of oral medications, called CFTR modulators, for which around 80% of people with CF are genetically eligible in Europe. CFTR modulators partially restore ion transport and lead to a rapid and major improvement in clinical manifestations and lung function, presumably resulting in longer survival. CFTR modulators have been game-changing in the care of people with CF. However, many questions remain unanswered, such as the long-term effects of CFTR modulators, especially when treatment is started very early in life, or the new CF-related disease emerging due to CFTR modulators. Moreover, severe complications of CF, such as diabetes or cirrhosis, are not reversed on CFTR modulators and around 20% of people with CF bear CFTR variants leading to a CFTR protein that is unresponsive to CFTR modulators. Challenges also arise in adapting CF care to a changing disease. In this review article, we highlight the new questions and challenges emerging from this revolution in CF care.

A longitudinal study assessing the impact of elexacaftor/tezacaftor/ivacaftor on gut transit and function in people with cystic fibrosis using magnetic resonance imaging (MRI).

BACKGROUND: Gastrointestinal (GI) symptoms in cystic fibrosis (CF) are common and disruptive. The effect of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on the GI tract is not fully understood. The aim was to use magnetic resonance imaging (MRI) to determine if elexacaftor/tezacaftor/ivacaftor (ETI) changed GI function and transit. METHODS: This was an 18 month prospective, longitudinal, observational study. We enrolled 24 people with CF aged 12 years or older to undergo MRI scans before starting ETI and 3, 6, and 18 months after starting ETI. The primary outcome measure was change in oro-caecal transit time (OCTT) at 6 and 18 months. Secondary outcome measures included change in small bowel water content (SBWC), change in the reduction in small bowel water content following a meal (DeltaSBWC) and change in total colonic volume (TCV). RESULTS: A total of 21 participants completed MRI scans at 6 months and 11 completed at 18 months. After 18 months of ETI, median OCTT significantly reduced, from >360 min [IQR 240->360] to 240 min [IQR 180-300] (p = 0.02, Wilcoxon signed-rank). Both SBWC and DeltaSBWC increased after starting ETI. TCV reduced significantly after 18 months (p = 0.005, Friedman). CONCLUSIONS: Our findings suggest an improvement in small bowel transit, small bowel response to food and a reduction in colonic volume after starting ETI. These effects may relate to CFTR activation in the small bowel. To our knowledge this is the first study to show a physiological change in GI transit and function in response to CFTR modulator use through imaging studies.

Factors associated with cystic fibrosis mortality before the age of 30: retrospective analysis of a cohort in southern Brazil.

The aim of this study was to retrospectively evaluate the factors associated with mortality before the age of 30 in adults with cystic fibrosis (CF) followed up at a referral center in southern Brazil. This study included individuals over 18 years of age. Clinical data related to childhood and the period of transition to an adult healthcare of individuals with CF were recorded, as well as spirometric and mortality data of individuals between 18 and 30 years of age. A total of 48 patients were included in this study, of which 28 (58.3%) were male. Comparing groups, we observed a higher prevalence of homozygosis for the F508del mutation (P=0.028), massive hemoptysis before the age of 18 (P=0.027), and lower values of pulmonary function, forced expiratory volume in the first second (FEV1) (%) (P=0.002), forced vital capacity (FVC) (%) (P=0.01), and FEV1/FVC (%) (P=0.001) in the group that died before age 30. F508del homozygosis, episodes of massive hemoptysis in childhood, and lower FEV1 values at age 18 were related to mortality before age 30 in a cohort of individuals with CF in southern Brazil.

Impact of day-to-day variation in FEV1 on measures of change: A conceptual description.

Clinical trials often demonstrate treatment efficacy through change in forced expiratory volume in one second (FEV1), comparing single FEV1 measurements from post- versus pre-treatment timepoints. Day-to-day variation in measured FEV1 is common for reasons such as diurnal variation and intermittent health changes, relative to a stable, monthly average. This variation can alter estimation of associations between change in FEV1 and baseline in predictable ways, through a phenomenon called regression to the mean. We quantify and explain day-to-day variation in percent-predicted FEV1 (ppFEV1) from 4 previous trials, and we present a statistical, data-driven explanation for potential bias in ceiling and floor effects due to commonly observed amounts of variation. We recommend accounting for variation when assessing associations between baseline value and change in CF outcomes in single-arm trials, and we consider possible impact of variation on conventional standards for study eligibility.

Impact of COVID-19 infection on lung function and nutritional status amongst individuals with cystic fibrosis: A global cohort study.

BACKGROUND: Factors associated with severe COVID-19 infection have been identified; however, the impact of infection on longer-term outcomes is unclear. The objective of this study was to examine the impact of COVID-19 infection on the trajectory of lung function and nutritional status in people with cystic fibrosis (pwCF). METHODS: This is a retrospective global cohort study of pwCF who had confirmed COVID-19 infection diagnosed between January 1, 2020 and December 31, 2021. Forced expiratory volume in one second percent predicted (ppFEV1) and body mass index (BMI) twelve months prior to and following a diagnosis of COVID-19 were recorded. Change in mean ppFEV1 and BMI were compared using a t-test. A linear mixed-effects model was used to estimate change over time and to compare the rate of change before and after infection. RESULTS: A total of 6,500 cases of COVID-19 in pwCF from 33 countries were included for analysis. The mean difference in ppFEV1 pre- and post-infection was 1.4 %, (95 % CI 1.1, 1.7). In those not on modulators, the difference in rate of change pre- and post-infection was 1.34 %, (95 % CI -0.88, 3.56) per year (p = 0.24) and -0.74 % (-1.89, 0.41) per year (p = 0.21) for those on elexacaftor/tezacaftor/ivacaftor. No clinically significant change was noted in BMI or BMI percentile before and after COVID-19 infection. CONCLUSIONS: No clinically meaningful impact on lung function and BMI trajectory in the year following infection with COVID-19 was identified. This work highlights the ability of the global CF community to unify and address critical issues facing pwCF.

Thymidine-dependent Staphylococcus aureus and lung function in patients with cystic fibrosis: a 10-year retrospective case-control study.

OBJECTIVE: Thymidine-dependent small-colony variants (TD-SCVs) of Staphylococcus aureus are being isolated with increasing frequency from patients with cystic fibrosis (CF). The aim of this study was to evaluate the relationship between TD-SCV isolation and pulmonary function in patients with CF, as well as to determine whether the emergence of TD-SCVs was associated with trimethoprim-sulfamethoxazole (TMP-SMX) use and with coinfection with other microorganisms. METHODS: This was a retrospective case-control study including patients with CF who visited the Clinical Hospital Complex of the Federal University of Paraná, in Curitiba, Brazil, between 2013 and 2022. Demographic, clinical, and spirometric data, as well as information on TD-SCVs and other isolated microorganisms, were collected from the medical records of patients with CF and TD-SCVs (TD-SCV group; n = 32) and compared with those of a matched group of patients with CF without TD-SCVs (control group; n = 64). RESULTS: Isolation of TD-SCVs was positively associated with TMP-SMX use (p = 0.009), hospitalization (p < 0.001), and impaired pulmonary function (p = 0.04). CONCLUSIONS: The use of TMP-SMX seems to contribute to the emergence of TD-SCVs, the isolation of which was directly associated with worse pulmonary function in our sample.

Silence of the lungs: comparing measures of slow and noncommunicating lung units from pulmonary function tests with computed tomography.

Multiple breath washout (MBW) has successfully assessed the silent lung zone particularly in cystic fibrosis lung disease, however, it is limited to the communicating lung only. There are a number of different pulmonary function methods that can assess what is commonly referred to as trapped air, with varying approaches and sensitivity. Twenty-five people with cystic fibrosis (pwCF) underwent MBW, spirometry, body plethysmography, and spirometry-controlled computed tomography (spiro-CT) on the same day. PwCF also performed extensions to MBW that evaluate air trapping, including our novel extension (MBWShX), which reveals the extent of underventilated lung units (UVLU). In addition, we used two previously established 5-breath methods that provide a volume of trapped gas (VTG). We used trapped air % from spiro-CT as the gold standard for comparison. UVLU derived from MBWShX showed the best agreement with trapped air %, both in terms of correlation (RS 0.89, P < 0.0001) and sensitivity (79%). Bland-Altman analysis demonstrated a significant underestimation of the VTG by both 5-breath methods (-249 mL [95% CI -10,796; 580 mL] and -203 mL [95% CI -997; 591 mL], respectively). Parameters from both spirometry and body plethysmography were suboptimal at assessing this pathophysiology. The parameters from MBWShX demonstrated the best relationship with spiro-CT and had the best sensitivity compared with the other pulmonary function methods assessed in this study. MBWShX shows promise to assess and monitor this critical pathophysiological feature, which has been shown to be a driver of lung disease progression in pwCF.NEW & NOTEWORTHY We consider the term "trapped air" either in the use of imaging or pulmonary function testing, something of a misnomer that can lead to an inaccurate assessment of an important physiological feature. Instead, we propose the term underventilated lung units (UVLU). Of the many pulmonary function methods we used in this study, we found that the use of multiple breath washout with short extension (MBWShX) to be the best nonimaging method.

The continuing need for dornase alfa for extracellular airway DNA hydrolysis in the era of CFTR modulators.

INTRODUCTION: The availability of cystic fibrosis transmembrane conductance regulator (CFTR) modulators opens the possibility of discontinuing some chronic pulmonary therapies to decrease cystic fibrosis (CF) treatment burden. However, CFTR modulators may not adequately address neutrophilic inflammation, which contributes to a self-perpetual cycle of viscous CF sputum, airway obstruction, inflammation, and lung function decline. AREAS COVERED: This review discusses the emerging role of neutrophil extracellular traps in CF and its role in CF sputum viscosity, airway obstruction, and inflammation, based on a literature search of PubMed (1990-present). We summarize clinical trials and real-world studies that support the efficacy of dornase alfa (Pulmozyme) in improving lung function and reducing pulmonary exacerbation in people with CF (PwCF), and we discuss the potential role of dornase alfa in reducing airway inflammation. We also examine the findings of short-term trials evaluating the discontinuation of mucoactive therapy in PwCF receiving CFTR modulators. EXPERT OPINION: Long-term studies are needed to assess the impact of discontinuing mucoactive therapy in PwCF who are clinically stable while receiving CFTR modulatory therapy. Treatment decisions should take into account the severity of underlying lung disease. People with advanced CF will likely require ongoing mucoactive therapy.

Lower physical activity levels in youth with Cystic Fibrosis compared to healthy controls: A multicentre comparative study.

BACKGROUND: Regular physical activity (PA) offers significant health benefits on both short (i.e., emotional well-being) and long term (i.e., fewer hospitalizations) in Youth with Cystic Fibrosis (YwCF). Regardless, evidence on PA levels in YwCF compared to healthy controls (HC) is inconsistent. Additionally, PA is a multidimensional outcome influenced by several factors such as Quadriceps strength and functional performance. Therefore, we aimed to assess whether PA, Quadriceps strength and functional performance differ between YwCF and HC across different age groups (i.e., children and adolescents). METHODS: YwCF aged 6-17 from two Belgian CF centres and age- and sex-matched HC were recruited. PA was measured with an ActiGraph GT3X + BT during 7 consecutive days. Isometric Quadriceps strength was assessed with a Hand Held Dynamometer and functional performance with a sit-to stand test (STS) and standing long jump (SLJ). RESULTS: A total of 49 YwCF (44 % male; 11.3 ± 3.3 years) and 49 HC (48 % male; 11.9 ± 3.5 years) were included. On average days, YwCF performed 4 ± 6.4 min less light PA and 7.5 ± 6.7 min less moderate-to-vigorous PA compared to HC (p = 0.04; p = 0.01). The differences in moderate-to-vigorous PA seem more pronounced in children (6-11 years)(p = 0.04). Furthermore, YwCF had similar Quadriceps strength to HC but had lower scores on the STS and SLJ (p = 0.50, p = 0.08; p = 0.02). CONCLUSIONS: This study shows lower PA levels and functional performance for YwCF, indicating that there is an urgent need for interventions promoting PA in YwCF. PA promotion will become increasingly important in the post modulator area to prevent health risks associated with low PA.

Potential, Pitfalls, and Future Directions for Remote Monitoring of Chronic Respiratory Diseases: Multicenter Mixed Methods Study in Routine Cystic Fibrosis Care.

BACKGROUND: The current literature inadequately addresses the extent to which remote monitoring should be integrated into care models for chronic respiratory diseases (CRDs). OBJECTIVE: This study examined a remote monitoring program (RMP) in cystic fibrosis (CF) by exploring experiences, future perspectives, and use behavior over 3 years, with the aim of developing future directions for remote monitoring in CRDs. METHODS: This was a mixed methods, multicenter, observational study in 5 Dutch CF centers following a sequential explanatory design. Self-designed questionnaires using the technology acceptance model were sent out to people with CF who had a minimum of 12 months of experience with the RMP and local health care professionals (HCPs). Questionnaire outcomes were used to inform semistructured interviews with HCPs and people with CF. Qualitative findings were reported following the COREQ (Consolidated Criteria for Reporting Qualitative Research) checklist. Anonymous data on use frequency of all people with CF were analyzed. RESULTS: Between the second quarter of 2020 and the end of 2022, a total of 608 people with CF were enrolled in the program, and a total of 9418 lung function tests and 2631 symptom surveys were conducted. In total, 65% (24/37) of HCPs and 89% (72/81) of people with CF responded to the questionnaire, and 7 HCPs and 12 people with CF participated in semistructured interviews. Both people with CF and HCPs were positive about remote monitoring in CF care and found the RMP a good addition to daily care (people with CF: 44/72, 61%; HCPs: 21/24, 88%). Benefits ranged from supporting individual patients to reducing health care consumption. The most valued monitoring tool was home spirometry by both people with CF (66/72, 92%) and HCPs (22/24, 92%). Downsides included the potential to lose sight of patients and negative psychosocial effects, as 17% (12/72) of people with CF experienced some form of stress due to the RMP. A large majority of people with CF (59/72, 82%) and HCPs (22/24, 92%) wanted to keep using the RMP in future, with 79% (19/24) of HCPs and 75% (54/72) of people with CF looking forward to more replacement of in-person care with digital care during periods of well-being. Future perspectives for the RMP were centered on creating hybrid care models, personalizing remote care, and balancing individual benefits with monitoring burden. CONCLUSIONS: Remote monitoring has considerable potential in supporting people with CF and HCPs within the CF care model. We identified 4 practice-based future directions for remote monitoring in CF and CRD care. The strategies, ranging from patient driven to prediction driven, can help clinicians, researchers, and policy makers navigate the rapidly changing digital health field, integrate remote monitoring into local care models, and align remote care with patient and clinician needs.

Cystic fibrosis.

Cystic fibrosis is a rare genetic disease caused by mutations in CFTR, the gene encoding cystic fibrosis transmembrane conductance regulator (CFTR). The discovery of CFTR in 1989 has enabled the unravelling of disease mechanisms and, more recently, the development of CFTR-directed therapeutics that target the underlying molecular defect. The CFTR protein functions as an ion channel that is crucial for correct ion and fluid transport across epithelial cells lining the airways and other organs. Consequently, CFTR dysfunction causes a complex multi-organ disease but, to date, most of the morbidity and mortality in people with cystic fibrosis is due to muco-obstructive lung disease. Cystic fibrosis care has long been limited to treating symptoms using nutritional support, airway clearance techniques and antibiotics to suppress airway infection. The widespread implementation of newborn screening for cystic fibrosis and the introduction of a highly effective triple combination CFTR modulator therapy that has unprecedented clinical benefits in up to 90% of genetically eligible people with cystic fibrosis has fundamentally changed the therapeutic landscape and improved prognosis. However, people with cystic fibrosis who are not eligible based on their CFTR genotype or who live in countries where they do not have access to this breakthrough therapy remain with a high unmet medical need.

Medication adherence to CFTR modulators in patients with cystic fibrosis: a systematic review.

BACKGROUND: In the last decade, a fundamental shift in the treatment of cystic fibrosis (CF) took place due to the introduction of CF transmembrane conductance regulator (CFTR) modulators. Adequate medication adherence is a prerequisite for their effectiveness, but little is known about adherence to CFTR modulators. We aimed to assess the extent of medication adherence to CFTR modulators in patients with CF and assess which characteristics are associated with adherence. METHODS: A systematic review following PRISMA guidelines was performed. Studies needed to report adherence to CFTR modulators. Main outcomes were: 1) level of medication adherence and 2) associations of demographic and/or clinical characteristics with adherence. RESULTS: In total, 4082 articles were screened and 21 full-text papers were assessed for eligibility. Ultimately, seven studies were included. Most studies were retrospective and focused on adherence to ivacaftor or lumacaftor-ivacaftor with only one focusing on elexacaftor-tezacaftor-ivacaftor. The majority used pharmacy refill data with adherence determined with the proportion of days covered (PDC) or the medication possession ratio (MPR). One study additionally used electronic monitoring and patient self-reported adherence. Adherence was 0.62-0.99 based on pharmacy data (PDC or MPR), 61% via electronic monitoring and 100% via self-report. Age <18 years appeared to be associated with good adherence, as was a higher lung function. CONCLUSIONS: Despite the wide variety of adherence methods used, adherence to CFTR modulators is suboptimal, based on objective measures such as pharmacy refill data or electronic monitoring. CFTR modulator adherence measurement and definitions requires more standardisation with a preference for objective and granular methods.

Development and validation of a novel questionnaire to describe and assess sensations and triggers associated with refractory and unexplained chronic cough.

INTRODUCTION: Refractory or unexplained chronic cough (RUCC) is a common clinical problem with no effective diagnostic tools. The Sensations and Triggers Provoking Cough questionnaire (TOPIC) was developed to characterise cough in RUCC versus cough in other conditions. METHODS: Content analysis of participant interviews discussing the sensations and triggers of chronic cough informed TOPIC development. Participants with chronic cough completed the draft-TOPIC (a subset repeating 5-7 days later), St George's Respiratory Questionnaire (SGRQ), Cough Severity Diary (CSD) and Global Rating of Change Scale. The draft-TOPIC item list was reduced in hierarchical and Rasch analysis to refine the questionnaire to the TOPIC. RESULTS: 49 items describing the triggers and sensations of cough were generated from participant interviews (RUCC n=14, chronic obstructive pulmonary disease (COPD) n=11, interstitial lung disease (ILD) n=10, asthma n=11, bronchiectasis n=3, cystic fibrosis n=7). 140 participants (median age 60.0 (19.0-88.0), female 56.4%; RUCC n=39, ILD n=38, asthma n=45, COPD n=6, bronchiectasis n=12) completed draft-TOPIC, where items with poor 'fit' for RUCC were removed to create TOPIC (8 trigger items, 7 sensation items). Median TOPIC score was significantly higher in RUCC (37.0) vs ILD (24.5, p=0.009) and asthma (7.0, p<0.001), but not bronchiectasis (20.0, p=0.318) or COPD (18.5, p=0.238), likely due to small sample sizes. The Rasch model demonstrated excellent fit in RUCC (χ2=22.04, p=0.85; PSI=0.88); as expected. When all participant groups were included, fit was no longer demonstrated (χ2=66.43, p=0.0001, PSI=0.89) due to the increased heterogeneity (CI=0.077). TOPIC correlated positively with SGRQ (r=0.47, p<0.001) and CSD (r=0.63, p<0.001). The test-retest reliability of TOPIC (intraclass correlation coefficient) was excellent (r=0.90, p<0.001). CONCLUSIONS: High TOPIC scores in the RUCC patients suggest their cough is characterised by specific sensations and triggers. Validation of TOPIC in cough clinics may demonstrate value as an aid to identify features of RUCC versus cough in other conditions.

Definitions of pulmonary exacerbation in people with cystic fibrosis: a scoping review.

BACKGROUND: Pulmonary exacerbations (PExs) are clinically important in people with cystic fibrosis (CF). Multiple definitions have been used for PEx, and this scoping review aimed to identify the different definitions reported in the literature and to ascertain which signs and symptoms are commonly used to define them. METHODS: A search was performed using Embase, MEDLINE, Cochrane Library, Scopus and CINAHL. All publications reporting clinical trials or prospective observational studies involving definitions of PEx in people with CF published in English from January 1990 to December 2022 were included. Data were then extracted for qualitative thematic analysis. RESULTS: A total of 14 039 records were identified, with 7647 titles and abstracts screened once duplicates were removed, 898 reviewed as full text and 377 meeting the inclusion criteria. Pre-existing definitions were used in 148 publications. In 75% of papers, an objective definition was used, while 25% used a subjective definition, which subcategorised into treatment-based definitions (76%) and those involving clinician judgement (24%). Objective definitions were subcategorised into three groups: those based on a combination of signs and symptoms (50%), those based on a predefined combination of signs and symptoms plus the initiation of acute treatment (47%) and scores involving different clinical features each with a specific weighting (3%). The most common signs and symptoms reported in the definitions were, in order, sputum production, cough, lung function, weight/appetite, dyspnoea, chest X-ray changes, chest sounds, fever, fatigue or lethargy and haemoptysis. CONCLUSION: We have identified substantial variation in the definitions of PEx in people with CF reported in the literature. There is a requirement for the development of internationally agreed-upon, standardised and validated age-specific definitions. Such definitions would allow comparison between studies and effective meta-analysis to be performed and are especially important in the highly effective modulator therapy era in CF care.

INSIGHTS INTO THE ORIGINS OF CYSTIC FIBROSIS LUNG DISEASE.

In this paper, I will discuss recent studies using a cystic fibrosis pig model to better understand the origins of cystic fibrosis lung disease. Specifically, I will review our work investigating how loss of the cystic fibrosis transmembrane conductance regulator function (CFTR) impairs mucociliary transport in the cystic fibrosis airway. These studies reveal new insights into the early, underlying mechanisms of cystic fibrosis lung disease and could lead to novel therapeutic interventions.