Bronchiectasis

The bronchiectasis microbiome: current understanding and treatment implications

PURPOSE OF REVIEW

Advances in DNA sequencing and analysis of the respiratory microbiome highlight its close association with bronchiectasis phenotypes, revealing fresh opportunities for diagnosis, stratification, and personalized clinical intervention. An under-recognized condition, bronchiectasis is increasingly the subject of recent large-scale, multicentre, and longitudinal clinical studies including detailed analysis of the microbiome. In this review, we summarize recent progress in our understanding of the bronchiectasis microbiome within the context of its potential use in treatment decisions.

RECENT FINDINGS

Diverse microbiome profiles exist in bronchiectasis, in line with the established disease heterogeneity including treatment response. Classical microbiology has established Pseudomonas aeruginosa and Haemophilus influenza as two microbial markers of disease, while holistic microbiome analysis has uncovered important associations with less common bacterial taxa including commensal an/or pathobiont species, including the emerging role of the fungal mycobiome, virome, and interactome. Integration of airway microbiomes with other high-dimensional biological and clinical datasets holds significant promise to determining treatable traits and mechanisms of disease related to the microbiome.

SUMMARY

The bronchiectasis microbiome is an emerging and key area of study with significant implications for understanding bronchiectasis, influencing treatment decisions and ultimately improving patient outcomes.

Outer membrane vesicle contributes to the Pseudomonas aeruginosa resistance to antimicrobial peptides in the acidic airway of bronchiectasis patients

Pseudomonas aeruginosa is the predominant pathogen causing chronic infection in the airway of patients with bronchiectasis (BE), a chronic respiratory disease with high prevalence worldwide. Environmental factors are vital for bacterial successful colonization. Here, with sputa and bronchoalveolar lavage fluids, we determined that the concentration of airway antimicrobial peptide LL-37 and lactate was elevated in BE patients, especially in those infected with P. aeruginosa. The in vitro antibacterial assay revealed the bactericidal activity of LL-37 against the clinical P. aeruginosa isolates, which were dampened in the acidic condition. P. aeruginosa production of outer membrane vesicles (OMVs) enhanced in the lactate-adjusted acidic condition. Transcriptomic analysis suggested that OMVs induce the hyperproduction of the chemical compound 2-heptyl-4-quinolone (HHQ) in the bacterial population, which was verified by high-performance liquid chromatography. The positively charged HHQ interfered with the binding of LL-37 to bacterial cell membrane, potentiating the P. aeruginosa resistance to LL-37. To our knowledge, this is a new resistance mechanism of P. aeruginosa against antimicrobial peptides and may provide theoretical support for the development of new antibacterial therapies.

Association between preserved ratio impaired spirometry and 1-year clinical outcomes in patients with bronchiectasis patients: A cohort study

BACKGROUND

Preserved Ratio Impaired Spirometry (PRISm) (defined as the ratio of forced expired volume in the first second to forced vital capacity (FEV1/FVC) greater than 0·70 with a FEV1 of less than 80% predicted) is associated with a higher risk of hospitalizations and mortality in the general population. However, less is known about whether PRISm is associated with adverse clinical outcomes in patients with bronchiectasis. We aimed to investigate whether PRISm is associated with adverse clinical outcomes in bronchiectasis patients.

METHODS

We performed a retrospective cohort study with inpatients admitted with acute exacerbations of bronchiectasis between January 2017 and January 2022. Clinical data including anthropometry, spirometry, laboratory, etiological and radiologic variables were collected. Patients were divided into the normal spirometry group, the PRISm group and the obstructive spirometry group. All patients were followed up for 1 year. The primary outcome was readmission of bronchiectasis at 1 year.

RESULTS

Of 487 bronchiectasis patients, we found 142 (29.2%) had normal spirometry, 67 (13.8%) had PRISm and 278 (57.1%) had obstructive spirometry. Patients with obstructive spirometry were more likely to be male and to smoke, had higher fibrinogen values and more lobes affected. Patients with PRISm (HR 1.929, 95% CI 1.049 to 3.546) and obstructive spirometry (HR 2.406, 95%CI 1.506 to 3.845) had a higher risk of readmissions compared with those with normal spirometry after adjustment for potential confounders.

CONCLUSIONS

PRISm was associated with significant increased risk for readmissions in patients with bronchiectasis compared with normal spirometry, which should receive special attention.

Targeting neutrophil serine proteases in bronchiectasis

Persistent neutrophilic inflammation is a central feature in both the pathogenesis and progression of bronchiectasis. Neutrophils release neutrophil serine proteases (NSPs), such as neutrophil elastase (NE), cathepsin G and proteinase 3. When chronically high levels of free NSP activity exceed those of protective antiproteases, structural lung destruction, mucosal-related defects, further susceptibility to infection and worsening of clinical outcomes can occur. Despite the defined role of prolonged, high levels of NSPs in bronchiectasis, no drug that controls neutrophilic inflammation is licensed for the treatment of bronchiectasis. Previous methods of suppressing neutrophilic inflammation (such as direct inhibition of NE) have not been successful; however, an emerging therapy designed to address neutrophil-mediated pathology, inhibition of the cysteine protease cathepsin C (CatC, also known as dipeptidyl peptidase 1), is a promising approach to ameliorate neutrophilic inflammation, since this may reduce the activity of all NSPs implicated in bronchiectasis pathogenesis, and not just NE. Current data suggest that CatC inhibition may effectively restore the protease-antiprotease balance in bronchiectasis and improve disease outcomes as a result. Clinical trials for CatC inhibitors in bronchiectasis have reported positive phase III results. In this narrative review, we discuss the role of high NSP activity in bronchiectasis, and how this feature drives the associated morbidity and mortality seen in bronchiectasis. This review discusses therapeutic approaches aimed at treating neutrophilic inflammation in the bronchiectasis lung, summarising clinical trial outcomes and highlighting the need for more treatment strategies that effectively address chronic neutrophilic inflammation in bronchiectasis.

Disease Severity and Activity in Bronchiectasis: A Paradigm Shift in Bronchiectasis Management

Bronchiectasis has an increasing prevalence and substantial clinical and economic burden. Therefore, physicians should identify patients with bronchiectasis at high risk of disease progression to ensure optimal management in advance. The heterogeneity of bronchiectasis means it is unlikely that any single parameter could identify highrisk patients; therefore, disease severity is usually assessed using validated composite tools, such as the Bronchiectasis Severity Index, FACED, and Bronchiectasis Aetiology Comorbidity Index, to predict long-term outcomes in bronchiectasis. Disease severity, however, implies an advanced process with lung destruction. Earlier intervention may prevent disease progression and improve outcomes. To identify patients at risk, rather than patients with established advanced disease, we need to shift our focus from disease severity to disease activity. Disease activity denotes the activation level of underlying pathophysiological processes and can be measured using clinical presentations and biomarkers. This review discusses a paradigm shift in bronchiectasis management, focusing on disease activity rather than severity, to prevent disease progression.

Infections, autoimmunity and immunodeficiencies are the leading etiologies of non-cystic fibrosis bronchiectasis in adults from the southwest of Colombia

INTRODUCTION

Non-cystic fibrosis bronchiectasis is a complex medical condition with multiple etiologies, characterized by chronic productive cough and radiologic evidence of airway lumen dilation and wall thickening. Associated exacerbations and declining lung function contribute to increasing disability and mortality. There are no data about the prevalence of non-cystic fibrosis bronchiectasis etiologies in the Colombian population.

OBJECTIVE

To investigate non-cystic fibrosis bronchiectasis etiology and clinical characteristics in adults evaluated in the southwest of Colombia.

MATERIALS AND METHODS

We conducted a cross-sectional, non-interventional study. Subjects diagnosed with non-cystic fibrosis bronchiectasis were referred to by their healthcare providers and then enrolled between October 2018 and April 2021. Medical records and radiological studies were evaluated. Participants underwent laboratory tests, including complete blood count, serum immunoglobulin levels, and, in some cases, additional tests.

RESULTS

We included 161 subjects. The average age was 50 years old, and 59% were females. Bronchiectasis etiology was identified in 84.6% of the cases. Postinfectious (34.6%) and immune disorders (25.3%), represented by autoimmunity (13.6%) and immunodeficiency (11.7%), were the leading causes. Gender differences were noted in autoimmune (females: 18.8% versus males: 6.1%, p = 0.021) and immunodeficiency-related bronchiectasis (males: 21.2% versus females 5.2%, p = 0.002). Immunodeficiencies-associated bronchiectases were more frequent in subjects under 50 years of age, while chronic obstructive pulmonary disease-associated bronchiectases were common in subjects over 50 years of age.

DISCUSSION

The etiologies of non-cystic fibrosis bronchiectasis in Colombia are diverse, exhibiting notable differences from other global regions. Serum immunoglobulin levels and clinical immunologist consultation should be prioritized in diagnosing patients with unclear bronchiectasis etiology, particularly those with recurrent sinopulmonary infections.

Prevalence and Clinical Implications of Pulmonary Vein Stenosis in Bronchiectasis: A 3D Reconstruction CT Study

BACKGROUND

Recent studies on bronchiectasis have revealed significant structural abnormalities and pathophysiological changes. However, there is limited research focused on pulmonary venous variability and congenital variation. Through our surgical observations, we noted that coarctation of pulmonary veins and atrophied lung volume are relatively common in bronchiectasis patients. Therefore, we conducted a retrospective study to explore pulmonary venous variation and secondary manifestations in bronchiectasis cases, utilizing 3D reconstruction software (Mimics Innovation Suite 21.0, Materialise Dental, Leuven, Belgium) to draw conclusions supported by statistical evidence.

METHOD

This retrospective study included patients with bronchiectasis and healthy individuals who underwent CT examinations at Beijing Chao-Yang Hospital between January 2017 and July 2023. Chest CT data were reconstructed using Materialise Mimics. Pulmonary veins and lung lobes were segmented from surrounding tissue based on an appropriate threshold determined by local grey values and image gradients. Subsequently, venous cross-sectional areas and lung volumes were measured for statistical analysis.

RESULT

CT data from 174 inpatients with bronchiectasis and 75 cases from the health examination center were included. Three-dimensional reconstruction data revealed a significant reduction in cross-sectional areas of pulmonary veins in the left lower lobe (p < 0.001), the right lower lobe (p = 0.030), and the right middle lobe (p = 0.009) of bronchiectasis patients. Subgroup analyses indicated that approximately 73.5% of localized cases of the left lower lobe exhibited pulmonary vein stenosis, while in the diffuse group, this proportion was only 52.6%. Furthermore, the cross-sectional area of pulmonary veins had a gradually decreasing trend, based on a small sample. Lung function tests showed significant reductions in FEV1, FVC, and FEV1% in bronchiectasis patients, attributed to the loss of lung volume in the left lower lobe, which accounted for 60.9% of the included sample.

CONCLUSIONS

Our recent findings suggest that pulmonary venous stenosis is a common variation in bronchiectasis and is often observed concurrently with reduced lung volume, particularly affecting the left lower lobe. Moreover, localized cases are more likely to suffer from pulmonary venous stenosis, with an ambiguous downtrend as the disease progresses. In conclusion, increased attention to pulmonary venous variation in bronchiectasis is warranted, and exploring new therapies to intervene in the early stages or alleviate obstruction may be beneficial.

Association of short-term exposure to ambient air pollution and temperature with bronchiectasis mortality: a nationwide time-stratified case-crossover study

BACKGROUND

Ambient pollution and non-optimal temperature are major risk factors for respiratory health. However, the relationships between short-term exposure to these factors and bronchiectasis mortality remain unknown.

METHODS

A nationwide, time-stratified case-crossover study across Mainland China was conducted from 2013 to 2019. Records of bronchiectasis deaths were extracted from the National Death Registration Reporting Information System. Daily concentrations of fine particulate matter (PM2.5), coarse particulate matter (PM2.5-10), nitrogen dioxide (NO2), ozone (O3), and daily temperature were obtained from high-resolution prediction models. We utilized conditional logistic regression model and distributed lag nonlinear model to explore the associations of these exposures with bronchiectasis mortality.

FINDINGS

We included a total of 19,320 bronchiectasis deaths. Air pollutant was associated with bronchiectasis mortality within the first 3 days after exposure and the exposure-response relationships were almost linear. An interquartile range increase in PM2.5, PM2.5-10, and O3 was associated with increments of 3.18%, 4.14%, and 4.36% in bronchiectasis mortality at lag 02 d, respectively. Additionally, lower temperature was associated with higher odds of bronchiectasis mortality. Compared to referent temperature (23.6 °C), the odds ratio for bronchiectasis mortality associated with extremely low temperature (P1: -13.4 °C) was 1.54 (95% CI: 1.05, 2.25).

INTERPRETATION

This national study provides compelling evidence, and highlights the necessity and importance of reducing air pollution exposures and keeping warm for susceptible populations.

FUNDING

National Natural Science Foundation of China (81925001; 82330070); Innovation Program of Shanghai Municipal Education Commission (202101070007-E00097); Program of Shanghai Municipal Science and Technology Commission (21DZ2201800); Program of Shanghai Shenkang Development Center (SHDC12023110); and Major Project of National Health Commission of China.

Characteristics of different pathogenic bacterial infections and their effects on prognosis in adult patients with bronchiectasis

The present study aimed to analyse the types of pathogens infecting adults with bronchiectasis and the effects of different pathogens on the number of acute exacerbations and the length of hospitalization for 1 year in patients with severe bronchiectasis. A total of 522 patients with bronchiectasis admitted to the Department of Respiratory and Critical Care Medicine at the Second Hospital of Jiaxing (Zhejiang, China) between January 2019 and December 2022 were retrospectively analysed. The patients were divided into a mild to moderate group and a severe group according to the bronchiectasis severity index criteria. The basic and clinical information of all the patients was collected. The patients were followed up for 1 year after the day when the sputum or alveolar lavage fluid samples tested positive for pathogens. The follow-up information included the exacerbation of cough symptoms, the number of hospitalizations and the number of days of antibiotic use in patients with bronchiectasis. A total of 522 patients with bronchiectasis were positive for pathogens, including 192 patients with Pseudomonas aeruginosa (P. aeruginosa; 36.8%), 60 patients with Klebsiella pneumoniae (K. pneumoniae; 11.5%), 48 patients with mixed pathogens (≥2 pathogens at the same time; 9.2%), 36 patients with Staphylococcus aureus (6.9%), 33 patients with Aspergillus fumigatus (6.3%), 30 patients with Haemophilus influenzae (5.7%), 15 patients with Acinetobacter baumannii (A. baumannii; 2.9%) and 108 patients with other pathogens (20.7%). Compared with patients with mild to moderate bronchiectasis, patients with severe bronchiectasis were more likely to have P. aeruginosa but less likely to have K. pneumoniae and other pathogens. The length of hospitalization and duration of antibiotic use in the severe group of patients with bronchiectasis caused by P. aeruginosa, A. fumigatus, or A. baumannii were significantly longer than those in the mild to moderate group. During the 1-year follow-up, the number of acute exacerbations and hospitalizations of patients with severe bronchiectasis caused by A. baumannii and P. aeruginosa were significantly greater than those of patients with severe bronchiectasis caused by other pathogens. According to logistic regression analysis, A. baumannii and P. aeruginosa were independent risk factors for acute exacerbation of severe bronchiectasis in the following year. In patients with severe bronchiectasis, the pathogens A. baumannii, P. aeruginosa and A. fumigatus were independent risk factors for future acute exacerbations and increased risk of hospitalization.

Mining single-cell data for cell type-disease associations

A robust understanding of the cellular mechanisms underlying diseases sets the foundation for the effective design of drugs and other interventions. The wealth of existing single-cell atlases offers the opportunity to uncover high-resolution information on expression patterns across various cell types and time points. To better understand the associations between cell types and diseases, we leveraged previously developed tools to construct a standardized analysis pipeline and systematically explored associations across four single-cell datasets, spanning a range of tissue types, cell types and developmental time periods. We utilized a set of existing tools to identify co-expression modules and temporal patterns per cell type and then investigated these modules for known disease and phenotype enrichments. Our pipeline reveals known and novel putative cell type-disease associations across all investigated datasets. In addition, we found that automatically discovered gene co-expression modules and temporal clusters are enriched for drug targets, suggesting that our analysis could be used to identify novel therapeutic targets.

Autologous transplantation of P63+ lung progenitor cells in patients with bronchiectasis: A randomized, single-blind, controlled trial

Non-cystic fibrosis bronchiectasis is a progressive respiratory disease with limited treatment options, prompting the exploration of regenerative therapies. This study investigates the safety and efficacy of autologous P63+ progenitor cell transplantation in a randomized, single-blind, controlled, phase 1/2 trial. Thirty-seven patients receive bronchoscopic airway clearance (B-ACT) (n = 19) or B-ACT plus P63+ progenitor cells (n = 18). Results show that compared to the control group, the change in DLCO levels from baseline to 24 weeks post therapy is significantly higher in the cell treatment group (p value = 0.039). Furthermore, the patients in the cell treatment group demonstrate significantly reduced lung damaged area, improved SGRQ score, and ameliorated BSI and FACED scores within 4-12 weeks post therapy. Transcriptomic analysis reveals that progenitor cells with higher expression of P63 gene have better therapeutic efficacy. These findings suggest that P63+ progenitor cells may offer a promising therapeutic approach for bronchiectasis. This study was registered at ClinicalTrials.gov(NCT03655808).

Analysis of factors influencing bronchiectasis patients with active pulmonary tuberculosis and development of a nomogram prediction model

Background

To identify the risk factors for bronchiectasis patients with active pulmonary tuberculosis (APTB) and to develop a predictive nomogram model for estimating the risk of APTB in bronchiectasis patients.

Methods

A retrospective cohort study was conducted on 16,750 bronchiectasis patients hospitalized at the Affiliated Hospital of Guangdong Medical University and the Second Affiliated Hospital of Guangdong Medical University between January 2019 and December 2023. The 390 patients with APTB were classified as the case group, while 818 patients were randomly sampled by computer at a 1:20 ratio from the 16,360 patients with other infections to serve as the control group. Relevant indicators potentially leading to APTB in bronchiectasis patients were collected. Patients were categorized into APTB and inactive pulmonary tuberculosis (IPTB) groups based on the presence of tuberculosis. The general characteristics of both groups were compared. Variables were screened using the least absolute shrinkage and selection operator (LASSO) analysis, followed by multivariate logistic regression analysis. A nomogram model was established based on the analysis results. The model's predictive performance was evaluated using calibration curves, C-index, and ROC curves, and internal validation was performed using the bootstrap method.

Results

LASSO analysis identified 28 potential risk factors. Multivariate analysis showed that age, gender, TC, ALB, MCV, FIB, PDW, LYM, hemoptysis, and hypertension are independent risk factors for bronchiectasis patients with APTB (p < 0.05). The nomogram demonstrated strong calibration and discrimination, with a C-index of 0.745 (95% CI: 0.715-0.775) and an AUC of 0.744 for the ROC curve. Internal validation using the bootstrap method produced a C-index of 0.738, further confirming the model's robustness.

Conclusion

The nomogram model, developed using common clinical serological characteristics, holds significant clinical value for assessing the risk of APTB in bronchiectasis patients.

[Management of adult bronchiectasis - Consensus-based Guidelines for the German Respiratory Society (DGP) e. V. (AWMF registration number 020-030)]

Bronchiectasis is an etiologically heterogeneous, chronic, and often progressive respiratory disease characterized by irreversible bronchial dilation. It is frequently associated with significant symptom burden, multiple complications, and reduced quality of life. For several years, there has been a marked global increase in the prevalence of bronchiectasis, which is linked to a substantial economic burden on healthcare systems. This consensus-based guideline is the first German-language guideline addressing the management of bronchiectasis in adults. The guideline emphasizes the importance of thoracic imaging using CT for diagnosis and differentiation of bronchiectasis and highlights the significance of etiology in determining treatment approaches. Both non-drug and drug treatments are comprehensively covered. Non-pharmacological measures include smoking cessation, physiotherapy, physical training, rehabilitation, non-invasive ventilation, thoracic surgery, and lung transplantation. Pharmacological treatments focus on the long-term use of mucolytics, bronchodilators, anti-inflammatory medications, and antibiotics. Additionally, the guideline covers the challenges and strategies for managing upper airway involvement, comorbidities, and exacerbations, as well as socio-medical aspects and disability rights. The importance of patient education and self-management is also emphasized. Finally, the guideline addresses special life stages such as transition, family planning, pregnancy and parenthood, and palliative care. The aim is to ensure comprehensive, consensus-based, and patient-centered care, taking into account individual risks and needs.

ACR Appropriateness Criteria® Tracheobronchial Disease

A variety of thoracic imaging modalities and techniques have been used to evaluate diseases of the trachea and central bronchi. This document evaluates evidence for the use of thoracic imaging in the evaluation of tracheobronchial disease, including clinically suspected tracheal or bronchial stenosis, tracheomalacia or bronchomalacia, and bronchiectasis. Appropriateness guidelines for initial imaging evaluation of tracheobronchial disease and for pretreatment planning or posttreatment evaluation are included. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The battle within: how Pseudomonas aeruginosa uses host-pathogen interactions to infect the human lung

Pseudomonas aeruginosa is a versatile Gram-negative pathogen known for its ability to invade the respiratory tract, particularly in cystic fibrosis patients. This review provides a comprehensive analysis of the multifaceted strategies for colonization, virulence, and immune evasion used by P. aeruginosa to infect the host. We explore the extensive protein arsenal of P. aeruginosa, including adhesins, exotoxins, secreted proteases, and type III and VI secretion effectors, detailing their roles in the infective process. We also address the unique challenge of treating diverse lung conditions that provide a natural niche for P. aeruginosa on the airway surface, with a particular focus in cystic fibrosis. The review also discusses the current limitations in treatment options due to antibiotic resistance and highlights promising future approaches that target host-pathogen protein-protein interactions. These approaches include the development of new antimicrobials, anti-attachment therapies, and quorum-sensing inhibition molecules. In summary, this review aims to provide a holistic understanding of the pathogenesis of P. aeruginosa in the respiratory system, offering insights into the underlying molecular mechanisms and potential therapeutic interventions.

Eosinophilic Bronchiectasis: Prevalence, Severity, and Associated Features-A Cohort Study

Background: Bronchiectasis (BE) has been traditionally associated with neutrophilic inflammation, but eosinophilic bronchiectasis (EB) has recently emerged. Data about prevalence, clinical features, and disease severity are lacking. This study aimed to assess the EB prevalence, compare EB with non-EB, evaluate the Type-2 (T2) high endotype in BE (T2-high EB) versus non-T2-high EB, and identify EB predictors. Methods: We conducted a prospective study involving 153 BE patients. The data collected included clinical, radiological, and microbiological findings. BE severity was assessed using the bronchiectasis severity index (BSI), FACED and E-FACED scores, and the bronchiectasis etiology and comorbidity index (BACI). EB was defined as a blood eosinophil count (BEC) ≥ 300 cells/μL, and T2-high EB as BEC ≥ 300 cells/μL with fractional exhaled nitric oxide (FeNO) ≥ 25 ppb. Results: Prevalence was 27% for EB and 20% for T2-high EB. EB patients exhibited poorer lung function and more severe radiologic features, with significantly higher severity scores [BSI, FACED, E-FACED, BACI (p < 0.05)], and a higher median exacerbation rate [4 (2-5) in EB vs. 2 (1-4) in non-EB, p = 0.0002], compared with non-EB patients. T2-high EB patients showed higher severity scores [BSI, FACED, E-FACED (p < 0.05)], as well as worse lung function parameters [FEV1%, FVC%, FEF 25-75% (p < 0.05)] compared with non-T2-high EB patients. In our study, patients with EB exhibited notably worsened lung function and higher BE severity scores compared with their non-EB counterparts, with exacerbations playing a major role in these differences. We found statistically significant positive correlations between BEC and disease severity scores, such as BSI, FACED, and mMRC, as well as an inverse relationship with pulmonary function. The likelihood of EB being present was significantly higher in association with mMRC ≥ 1 (OR = 2.53; 95% CI, 1.26-5.64), exacerbations/year ≥ 1 (OR = 1.27; 95% CI, 1.0-1.63), and chronic PA colonization (OR = 3.9; 95% CI, 1.08-15.8). Conclusions: EB is a distinct endotype. Dyspnea, exacerbations, and PA colonization may be predictive of EB, emphasizing the importance of early detection for improved outcomes. BEC could serve as a useful biomarker of disease severity to consider when diagnosing EB.

Novel cathepsin C inhibitor, BI 1291583, intended for treatment of bronchiectasis: Phase I characterization in healthy volunteers

Novel treatments are needed to reduce inflammation, improve symptoms, address exacerbations, and slow disease progression in bronchiectasis. Cathepsin C (CatC) inhibition promises to achieve this through reduction of neutrophil-derived serine protease (including neutrophil elastase [NE] and proteinase 3 [PR3]) activation. Here, we present the phase I characterization of the novel CatC inhibitor, BI 1291583. Five phase I trials of BI 1291583 in healthy subjects are presented: a single-rising-dose study (NCT03414008) and two multiple-rising-dose studies (NCT03868540 and NCT04866160) assessing the safety, tolerability, pharmacodynamics, and pharmacokinetics of BI 1291583; a food effect study (NCT03837964); and a drug-drug interaction study (NCT03890887) of BI 1291583 and itraconazole. BI 1291583 was safe and well tolerated across the doses tested in these trials. Most adverse events (AEs) were mild or moderate in intensity, with no serious AEs, AEs of special interest or deaths reported in any trial. Drug-related skin exfoliation was not reported more frequently in subjects treated with BI 1291583 compared with placebo. BI 1291583 was readily absorbed, and pharmacokinetics were supra-proportional over the dose ranges assessed. Additionally, BI 1291583 inhibited CatC in a dose-dependent manner, inhibited downstream NE activity, and decreased PR3 levels. No food effect was observed. Co-administration of multiple doses of itraconazole increased BI 1291583 exposure approximately twofold. Due to these promising phase I results, a multinational phase II program of BI 1291583 in adults with bronchiectasis is ongoing (Airleaf™ [NCT05238675], Clairafly™ [NCT05865886], and Clairleaf™ [NCT05846230]).

Dry Powder Inhaler Formulation of Lactobacillus rhamnosus GG Targeting Pseudomonas aeruginosa Infection in Bronchiectasis Maintenance Therapy

The inhaled delivery of lactic acid bacteria (LAB) probiotics has been demonstrated to exert therapeutic benefits to the lungs due to LAB's immunomodulatory activities. The development of inhaled probiotics formulation, however, is in its nascent stage limited to nebulized LAB. We developed a dry powder inhaler (DPI) formulation of lactobacillus rhamnosus GG (LGG) intended for bronchiectasis maintenance therapy by spray freeze drying (SFD). The optimal DPI formulation (i.e., LGG: mannitol: lactose: leucine = 35: 45: 15: 5 wt.%) was determined based on the aerosolization efficiency (86% emitted dose and 26% respirable fraction) and LGG cell viability post-SFD (7 log CFU/mL per mg powder). The optimal DPI formulation was evaluated and compared to lyophilized naked LGG by its (1) adhesion capacity and cytotoxicity to human lung epithelium cells (i.e., A549 and 16HBE14o- cells) as well as its (2) effectiveness in inhibiting the growth and adhesion of Pseudomonas aeruginosa to lung cells. The optimal DPI of LGG exhibited similar non-cytotoxicity and adhesion capacity to lung cells to naked LGG. The DPI of LGG also inhibited the growth and adhesion of P. aeruginosa to the lung cells as effectively as the naked LGG. The present work established the feasibility of delivering the LAB probiotic by the DPI platform without adversely affecting LGG's anti-pseudomonal activities.

Microbiological characteristics of the lower airway in adults with bronchiectasis: a prospective cohort study

BACKGROUND

Microbial infection and colonization are frequently associated with disease progression and poor clinical outcomes in bronchiectasis. Identification of pathogen spectrum is crucial for precision treatment at exacerbation of bronchiectasis.

METHODS

We conducted a prospective cohort study in patients with bronchiectasis exacerbation onset and stable state. Bronchoalveolar lavage fluid (BALF) was collected for conventional microbiological tests (CMTs) and metagenomic Next-Generation Sequencing (mNGS). Bronchiectasis patients were monitored for documenting the time to the next exacerbation during longitudinal follow-up.

RESULTS

We recruited 168 eligible participants in the exacerbation cohorts, and 38 bronchiectasis patients at stable state at longitudinal follow-up. 141 bronchiectasis patients at exacerbation onset had definite or probable pathogens via combining CMTs with mNGS reports. We identified that Pseudomonas aeruginosa, non-tuberculous mycobacteria, Haemophilus influenzae, Nocardia spp, and Staphylococcus aureus were the top 5 pathogens with a higher detection rate in our cohorts via combination of CMTs and mNGS analysis. We also observed strong correlations of Pseudomonas aeruginosa, Haemophilus influenzae, non-tuberculous mycobacteria with disease severity, including the disease duration, Bronchiectasis Severity Index, and lung function. Moreover, the adjusted pathogenic index of potential pathogenic microorganism negatively correlated (r = -0.7280, p < 0.001) with the time to the next exacerbation in bronchiectasis.

CONCLUSION

We have revealed the pathogenic microbial spectrum in lower airways and the negative correlation of PPM colonization with the time to the next exacerbation in bronchiectasis. These results suggested that pathogens contribute to the progression of bronchiectasis.

Bronchiectasis in Asia: a review of current status and challenges

Recent bronchiectasis studies from large-scale multinational, multicentre registries have demonstrated that the characteristics of the disease vary according to geographic region. However, most perspectives on bronchiectasis are dominated by data from Western countries. This review intends to provide an Asian perspective on the disease, focusing on the established registries in India, Korea and China. Asian patients with bronchiectasis are less likely to show female predominance and experience exacerbations, are more likely to be younger, have milder disease, and have fewer options for guideline-recommended treatment than those living in other global regions. Furthermore, Asian bronchiectasis patients demonstrate different comorbidities, microbiological profiles and unique endophenotypes, including post-tuberculosis and dry bronchiectasis. Notably, each Asian region reveals further geographic variations and inter-patient differences. Future studies are warranted to better characterise Asian patients with bronchiectasis.

A Bispecific Monoclonal Antibody Targeting Psl and PcrV Enhances Neutrophil-Mediated Killing of Pseudomonas aeruginosa in Patients with Bronchiectasis

Rationale: Pseudomonas aeruginosa infection is associated with worse outcomes in bronchiectasis. Impaired neutrophil antimicrobial responses contribute to bacterial persistence. Gremubamab is a bivalent, bispecific monoclonal antibody targeting Psl exopolysaccharide and the type 3 secretion system component PcrV. Objectives: This study evaluated the efficacy of gremubamab to enhance killing of P. aeruginosa by neutrophils from patients with bronchiectasis and to prevent P. aeruginosa-associated cytotoxicity. Methods: P. aeruginosa isolates from a global bronchiectasis cohort (n = 100) underwent whole-genome sequencing to determine target prevalence. Functional activity of gremubamab against selected isolates was tested in vitro and in vivo. Patients with bronchiectasis (n = 11) and control subjects (n = 10) were enrolled, and the effect of gremubamab in peripheral blood neutrophil opsonophagocytic killing (OPK) assays against P. aeruginosa was evaluated. Serum antibody titers to Psl and PcrV were determined (n = 30; 19 chronic P. aeruginosa infection, 11 no known P. aeruginosa infection), as was the effect of gremubamab treatment in OPK and anti-cytotoxic activity assays. Measurements and Main Results: Psl and PcrV were conserved in isolates from chronically infected patients with bronchiectasis. Seventy-three of 100 isolates had a full psl locus, and 99 of 100 contained the pcrV gene, with 20 distinct full-length PcrV protein subtypes identified. PcrV subtypes were successfully bound by gremubamab and the monoclonal antibody-mediated potent protective activity against tested isolates. Gremubamab increased bronchiectasis patient neutrophil-mediated OPK (+34.6 ± 8.1%) and phagocytosis (+70.0 ± 48.8%), similar to effects observed in neutrophils from control subjects (OPK, +30.1 ± 7.6%). No evidence of competition between gremubamab and endogenous antibodies was found, with protection against P. aeruginosa-induced cytotoxicity and enhanced OPK demonstrated with and without addition of patient serum. Conclusions: Gremubamab enhanced bronchiectasis patient neutrophil phagocytosis and killing of P. aeruginosa and reduced virulence.

Usefulness of Impulse Oscillometry in Predicting the Severity of Bronchiectasis

BACKGROUND

Bronchiectasis is a chronic respiratory disease that leads to airway inflammation, destruction, and airflow limitation, which reflects its severity. Impulse oscillometry (IOS) is a non-invasive method that uses sound waves to estimate lung function and airway resistance. The aim of this study was to assess the usefulness of IOS in predicting the severity of bronchiectasis.

METHODS

We retrospectively reviewed the IOS parameters and clinical characteristics in 145 patients diagnosed with bronchiectasis between March 2020 and May 2021. Disease severity was evaluated using the FACED score, and patients were divided into mild and moderate/severe groups.

RESULTS

Forty-four patients (30.3%) were in the moderate/severe group, and 101 (69.7%) were in the mild group. Patients with moderate/severe bronchiectasis had a higher airway resistance at 5 Hz (R5), a higher difference between the resistance at 5 and 20 Hz (R5-R20), a higher resonant frequency (Fres), and a higher area of reactance (AX) than patients with mild bronchiectasis. R5 ≥0.43, resistance at 20 Hz (R20) ≥0.234, R5-R20 ≥28.3, AX ≥1.02, reactance at 5 Hz (X5) ≤-0.238, and Fres ≥20.88 revealed significant univariable relationships with bronchiectasis severity (p<0.05). Among these, only X5 ≤-0.238 exhibited a significant multivariable relationship with bronchiectasis severity (p=0.039). The receiver operating characteristic curve for predicting moderate- to-severe bronchiectasis of FACED score based on IOS parameters exhibited an area under the curve of 0.809.

CONCLUSION

The IOS assessed by the disease severity of FACED score can effectively reflect airway resistance and elasticity in bronchiectasis patients and serve as valuable tools for predicting bronchiectasis severity.

Infection and the microbiome in bronchiectasis

Bronchiectasis is marked by bronchial dilatation, recurrent infections and significant morbidity, underpinned by a complex interplay between microbial dysbiosis and immune dysregulation. The identification of distinct endophenotypes have refined our understanding of its pathogenesis, including its heterogeneous disease mechanisms that influence treatment and prognosis responses. Next-generation sequencing (NGS) has revolutionised the way we view airway microbiology, allowing insights into the "unculturable". Understanding the bronchiectasis microbiome through targeted amplicon sequencing and/or shotgun metagenomics has provided key information on the interplay of the microbiome and host immunity, a central feature of disease progression. The rapid increase in translational and clinical studies in bronchiectasis now provides scope for the application of precision medicine and a better understanding of the efficacy of interventions aimed at restoring microbial balance and/or modulating immune responses. Holistic integration of these insights is driving an evolving paradigm shift in our understanding of bronchiectasis, which includes the critical role of the microbiome and its unique interplay with clinical, inflammatory, immunological and metabolic factors. Here, we review the current state of infection and the microbiome in bronchiectasis and provide views on the future directions in this field.

Bronchiectasis

Non-cystic fibrosis bronchiectasis, a condition that remains relatively underrecognized, has garnered increasing research focus in recent years. This scientific interest has catalyzed advancements in diagnostic methodologies, enabling comprehensive clinical and molecular profiling. Such progress facilitates the development of personalized treatment strategies, marking a significant step toward precision medicine for these patients. Bronchiectasis poses significant diagnostic challenges in both clinical settings and research studies. While computed tomography (CT) remains the gold standard for diagnosis, novel alternatives are emerging. These include artificial intelligence-powered algorithms, ultra-low dose chest CT, and magnetic resonance imaging (MRI) techniques, all of which are becoming recognized as feasible diagnostic tools. The precision medicine paradigm calls for refined characterization of bronchiectasis patients by analyzing their inflammatory and molecular profiles. Research into the underlying mechanisms of inflammation and the evaluation of biomarkers such as neutrophil elastase, mucins, and antimicrobial peptides have led to the identification of distinct patient endotypes. These endotypes present variable clinical outcomes, necessitating tailored therapeutic interventions. Among these, eosinophilic bronchiectasis is notable for its prevalence and specific prognostic factors, calling for careful consideration of treatable traits. A deeper understanding of the microbiome's influence on the pathogenesis and progression of bronchiectasis has inspired a holistic approach, which considers the multibiome as an interconnected microbial network rather than treating pathogens as solitary entities. Interactome analysis therefore becomes a vital tool for pinpointing alterations during both stable phases and exacerbations. This array of innovative approaches has revolutionized the personalization of treatments, incorporating therapies such as inhaled mannitol or ARINA-1, brensocatib for anti-inflammatory purposes, and inhaled corticosteroids specifically for patients with eosinophilic bronchiectasis.

Total sputum nitrate/nitrite is associated with exacerbations and Pseudomonas aeruginosa colonisation in bronchiectasis

Background

Sputum nitrate/nitrite, which is the main component of reactive nitrogen species, is a potential biomarker of disease severity and progression in bronchiectasis. This study aimed to determine the association between nitrate/nitrite and exacerbations and airway microbiota in bronchiectasis.

Methods

We measured total nitrate/nitrite concentration in sputum samples collected from 85 patients with stable bronchiectasis, performed 16S ribosomal RNA sequencing of sputum samples and predicted the denitrification ability of airway microbiota using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Relationships between sputum total nitrate/nitrite and disease severity, exacerbations and airway microbiota were examined.

Results

Higher total sputum nitrate/nitrite was associated with more severe bronchiectasis defined by E-FACED (exacerbation, forced expiratory volume in 1 s, age, chronic colonisation by Pseudomonas aeruginosa, radiological extension and dyspnoea) (p=0.003) or Bronchiectasis Severity Index (p=0.006) and more exacerbations in the prior 12 months (p=0.005). Moreover, total sputum nitrate/nitrite was significantly higher in patients with worse cough score (p=0.03), worse sputum purulence score (p=0.01) and worse Medical Research Council dyspnoea score (p=0.02). In addition, the total sputum nitrate/nitrite of the P. aeruginosa colonised (PA) group was higher than that of the non-P. aeruginosa colonised (NPA) group (p=0.04), and the relative abundance of P. aeruginosa was positively correlated with total nitrate/nitrite (r=0.337, p=0.002). Denitrification module (M00529) was also significantly enriched in the PA group compared to the NPA group through PICRUSt analyses. Using receiver-operating characteristic analysis, total nitrate/nitrite was associated with exacerbations during 1-year follow-up (area under the curve 0.741, p=0.014).

Conclusions

Sputum nitrate/nitrite is a biomarker of disease severity and associated with P. aeruginosa colonisation in bronchiectasis.

Lung microbiome: new insights into bronchiectasis' outcome

The present treatments for bronchiectasis, which is defined by pathological dilatation of the airways, are confined to symptom relief and minimizing exacerbations. The condition is becoming more common worldwide. Since the disease's pathophysiology is not entirely well understood, developing novel treatments is critically important. The interplay of chronic infection, inflammation, and compromised mucociliary clearance, which results in structural alterations and the emergence of new infection, is most likely responsible for the progression of bronchiectasis. Other than treating bronchiectasis caused by cystic fibrosis, there are no approved treatments. Understanding the involvement of the microbiome in this disease is crucial, the microbiome is defined as the collective genetic material of all bacteria in an environment. In clinical practice, bacteria in the lungs have been studied using cultures; however, in recent years, researchers use next-generation sequencing methods, such as 16S rRNA sequencing. Although the microbiome in bronchiectasis has not been entirely investigated, what is known about it suggests that Haemophilus, Pseudomonas and Streptococcus dominate the lung bacterial ecosystems, they present significant intraindividual stability and interindividual heterogeneity. Pseudomonas and Haemophilus-dominated microbiomes have been linked to more severe diseases and frequent exacerbations, however additional research is required to fully comprehend the role of microbiome in the evolution of bronchiectasis. This review discusses recent findings on the lung microbiota and its association with bronchiectasis.

Bronchiectasis management in adults: state of the art and future directions

Formerly regarded as a rare disease, bronchiectasis is increasingly recognised. A renewed interest in this disease has led to significant progress in bronchiectasis research. Randomised clinical trials (RCTs) have demonstrated the benefits of airway clearance techniques, inhaled antibiotics and long-term macrolide therapy in bronchiectasis patients. However, the heterogeneity of bronchiectasis remains one of the most challenging aspects of management. Phenotypes and endotypes of bronchiectasis have been identified to help find "treatable traits" and partially overcome disease complexity. The goals of therapy for bronchiectasis are to reduce the symptom burden, improve quality of life, reduce exacerbations and prevent disease progression. We review the pharmacological and non-pharmacological treatments that can improve mucociliary clearance, reduce airway inflammation and tackle airway infection, the key pathophysiological features of bronchiectasis. There are also promising treatments in development for the management of bronchiectasis, including novel anti-inflammatory therapies. This review provides a critical update on the management of bronchiectasis focusing on treatable traits and recent RCTs.

Improving the Diagnosis and Treatment of Paediatric Bronchiectasis Through Research and Translation

Bronchiectasis, particularly in children, is an increasingly recognised yet neglected chronic lung disorder affecting individuals in both low-to-middle and high-income countries. It has a high disease burden and there is substantial inequity within and between settings. Furthermore, compared with other chronic lung diseases, considerably fewer resources are available for children with bronchiectasis. The need to prevent bronchiectasis and to reduce its burden also synchronously aligns with its high prevalence and economic costs to health services and society. Like many chronic lung diseases, bronchiectasis often originates early in childhood, highlighting the importance of reducing the disease burden in children. Concerted efforts are therefore needed to improve disease detection, clinical management and equity of care. Modifiable factors in the causal pathways of bronchiectasis, such as preventing severe and recurrent lower respiratory infections should be addressed, whilst also acknowledging the role played by social determinants of health. Here, we highlight the importance of early recognition/detection and optimal management of bronchiectasis in children, and outline our research, which is attempting to address important clinical knowledge gaps discussed in a recent workshop. The research is grouped under three themes focussing upon primary prevention, improving diagnosis and disease characterisation, and providing better management. Our hope is that others in multiple settings will undertake additional studies in this neglected field to further improve the lives of people with bronchiectasis. We also provide a resource list with links to help inform consumers and healthcare professionals about bronchiectasis and its recognition and management.

Impact of Rheumatoid Arthritis and Seropositivity on the Risk of Non-Cystic Fibrosis Bronchiectasis

BACKGROUND

Despite the coexistence of bronchiectasis and rheumatoid arthritis (RA) and the poor prognosis associated with the combination of conditions, to our knowledge, no longitudinal studies that comprehensively evaluated whether patients with RA have a higher risk of bronchiectasis compared with those without RA have been published. Whether seropositivity is associated with an increased risk of bronchiectasis in RA is the subject of ongoing controversy.

RESEARCH QUESTION

Does RA influence the development of bronchiectasis? Is seropositivity associated with an increased risk of bronchiectasis in RA?

STUDY DESIGN AND METHODS

The incidence of bronchiectasis was compared between individuals with RA (n = 50,651; seropositive rheumatoid arthritis [SPRA]: n = 35,879 and seronegative rheumatoid arthritis [SNRA]: n = 14,772) and 1:5 age- and sex-matched control patients (n = 253,255) enrolled between 2010 and 2017 in the Korean National Health Insurance Service database. The participants were followed from 1 year after RA diagnosis or the corresponding index date to the date of bronchiectasis incidence, censored date, or December 2019.

RESULTS

The cumulative incidence of bronchiectasis at 9 years of follow-up was approximately 7% in participants with RA. During a median follow-up of 4.3 years (interquartile range, 2.6-6.3 years), participants with RA showed a 2.12-fold higher risk of developing bronchiectasis than matched control participants, even after adjusting for potential confounders related to bronchiectasis development (95% CI, 2.00-2.25). In an analysis of RA serologic status using a fully adjusted model, participants with SPRA and those with SNRA showed 2.34-fold (95% CI, 2.20-2.49) and 1.56-fold (95% CI, 1.40-1.73) increased risks, respectively, compared with matched control participants.

INTERPRETATION

Individuals with RA had approximately twice the risk of developing bronchiectasis than matched control individuals, even after adjusting for potential confounders. The increased risk was more evident in individuals with SPRA than in those with SNRA, implying that rheumatic inflammation plays a major role in the development of RA-bronchiectasis overlap.

Erdosteine in children and adults with bronchiectasis (BETTER trial): study protocol for a multicentre, double-blind, randomised controlled trial

INTRODUCTION

Bronchiectasis is a worldwide chronic lung disorder where exacerbations are common. It affects people of all ages, but especially Indigenous populations in high-income nations. Despite being a major contributor to chronic lung disease, there are no licensed therapies for bronchiectasis and there remain relatively few randomised controlled trials (RCTs) conducted in children and adults. Our RCT will address some of these unmet needs by evaluating whether the novel mucoactive agent, erdosteine, has a therapeutic role in children and adults with bronchiectasis.Our primary aim is to determine in children and adults aged 2-49 years with bronchiectasis whether regular erdosteine over a 12-month period reduces acute respiratory exacerbations compared with placebo. Our primary hypothesis is that people with bronchiectasis who regularly use erdosteine will have fewer exacerbations than those receiving placebo.Our secondary aims are to determine the effect of the trial medications on quality of life (QoL) and other clinical outcomes (exacerbation duration, time-to-next exacerbation, hospitalisations, lung function, adverse events). We will also assess the cost-effectiveness of the intervention.

METHODS AND ANALYSIS

We are undertaking an international multicentre, double-blind, placebo-RCT to evaluate whether 12 months of erdosteine is beneficial for children and adults with bronchiectasis. We will recruit 194 children and adults with bronchiectasis to a parallel, superiority RCT at eight sites across Australia, Malaysia and Philippines. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, exacerbation duration, time-to-next exacerbation, hospitalisations and lung function.

ETHICS AND DISSEMINATION

The Human Research Ethics Committees (HREC) of Children's Health Queensland (for all Australian sites), University of Malaya Medical Centre (Malaysia) and St. Luke's Medical Centre (Philippines) approved the study. We will publish the results and share the outcomes with the academic and medical community, funding and relevant patient organisations.

TRIAL REGISTRATION NUMBER

ACTRN12621000315819.

Dental management of Kartagener syndrome: A case report

BACKGROUND

Kartagener syndrome (KS) is recognized as an inherited, autosomal recessive disorder characterized by a combination of chronic sinusitis, bronchiectasis, and situs inversus. It affects one in 12,500-50,000 live births worldwide.

AIM

This paper aims to discuss the dental management of patients diagnosed with KS.

CASE REPORT

A 31-year-old male with KS manifests by impaired cilia motility which increases the risk of a frequent lung infection. The dental examination revealed that the patient required comprehensive oral hygiene care which included patient education and nonsurgical periodontal therapy under local anesthesia.

CONCLUSIONS

Dental care providers should ask affected patients with KS about their signs and symptoms of cardiac and pulmonary disease and seek consultation with their attending physician regarding these health concerns before the initiation of general anesthesia and perhaps conscious sedation administration. Patients with KS with emerging cardiac and/or respiratory impairment should be referred promptly for medical assessment.

Human nasal microbiota shifts in healthy and chronic respiratory disease conditions

BACKGROUND

An increasing number of studies investigate various human microbiotas and their roles in the development of diseases, maintenance of health states, and balanced signaling towards the brain. Current data demonstrate that the nasal microbiota contains a unique and highly variable array of commensal bacteria and opportunistic pathogens. However, we need to understand how to harness current knowledge, enrich nasal microbiota with beneficial microorganisms, and prevent pathogenic developments.

RESULTS

In this study, we have obtained nasal, nasopharyngeal, and bronchoalveolar lavage fluid samples from healthy volunteers and patients suffering from chronic respiratory tract diseases for full-length 16 S rRNA sequencing analysis using Oxford Nanopore Technologies. Demographic and clinical data were collected simultaneously. The microbiome analysis of 97 people from Lithuania suffering from chronic inflammatory respiratory tract disease and healthy volunteers revealed that the human nasal microbiome represents the microbiome of the upper airways well.

CONCLUSIONS

The nasal microbiota of patients was enriched with opportunistic pathogens, which could be used as indicators of respiratory tract conditions. In addition, we observed that a healthy human nasal microbiome contained several plant- and bee-associated species, suggesting the possibility of enriching human nasal microbiota via such exposures when needed. These candidate probiotics should be investigated for their modulating effects on airway and lung epithelia, immunogenic properties, neurotransmitter content, and roles in maintaining respiratory health and nose-brain interrelationships.

Pathophysiology of non-cystic fibrosis bronchiectasis in children and adolescents with asthma: A protocol for systematic review and meta-analysis

BACKGROUND

The pathophysiological mechanisms by which asthma and bronchiectasis are associated are still unclear. The association of these two diseases can result in more severe symptoms and a greater number of exacerbations.

OBJECTIVE

The aim of this systematic review is to collect evidence of the pathophysiology of non-cystic fibrosis bronchiectasis with associated asthma in children and adolescents, aged 6-18 years old.

METHODS

A systematic and comprehensive search will be performed using eight main databases, PubMed, PubMed PMC, BVS/BIREME, Scopus, EMBASE, Cochrane Library, Scielo and Web of Science. Articles will be searched from the earliest available time to July 2023. The studied population will be composed of children and adolescents with asthma and non-cystic fibrosis bronchiectasis. From the data obtained, all articles found will be transferred to the Rayyan platform. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols Checklist (PRISMA P-2015). In addition, if sufficient data are available, a meta-analysis will be conducted. Two independent reviewers will conduct the studies selection, data extraction, and risk of bias assessment. The outcome measures will be to analyze if non-cystic fibrosis bronchiectasis is related to a specific inflammatory profile.

DISCUSSION

A systematic review will provide better knowledge about the etiopathogenesis and causes of the association between asthma and bronchiectasis and its role in the severity and control of asthma. Identifying, selecting and critically evaluating studies on asthma and bronchiectasis, would be possible to illuminate the characteristics of children and adolescents with associated diagnoses and provide information to help individualized treatments in order to control and prevent complications. The findings of this study will be published in a peer-reviewed journal.

SYSTEMATIC REVIEW REGISTRATION

The systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) in July 2023 (registration number CRD42023440355).

Bronchiectasis-associated infections and outcomes in a large, geographically diverse electronic health record cohort in the United States

BACKGROUND

Bronchiectasis is a pulmonary disease characterized by irreversible dilation of the bronchi and recurring respiratory infections. Few studies have described the microbiology and prevalence of infections in large patient populations outside of specialized tertiary care centers.

METHODS

We used the Cerner HealthFacts Electronic Health Record database to characterize the nature, burden, and frequency of pulmonary infections among persons with bronchiectasis. Chronic infections were defined based on organism-specific guidelines.

RESULTS

We identified 7,749 patients who met our incident bronchiectasis case definition. In this study population, the organisms with the highest rates of isolate prevalence were Pseudomonas aeruginosa with 937 (12%) individuals, Staphylococcus aureus with 502 (6%), Mycobacterium avium complex (MAC) with 336 (4%), and Aspergillus sp. with 288 (4%). Among persons with at least one isolate of each respective pathogen, 219 (23%) met criteria for chronic P. aeruginosa colonization, 74 (15%) met criteria for S. aureus chronic colonization, 101 (30%) met criteria for MAC chronic infection, and 50 (17%) met criteria for Aspergillus sp. chronic infection. Of 5,795 persons with at least two years of observation, 1,860 (32%) had a bronchiectasis exacerbation and 3,462 (60%) were hospitalized within two years of bronchiectasis diagnoses. Among patients with chronic respiratory infections, the two-year occurrence of exacerbations was 53% and for hospitalizations was 82%.

CONCLUSIONS

Patients with bronchiectasis experiencing chronic respiratory infections have high rates of hospitalization.

Revised ISHAM-ABPA working group clinical practice guidelines for diagnosing, classifying and treating allergic bronchopulmonary aspergillosis/mycoses

BACKGROUND

The International Society for Human and Animal Mycology (ISHAM) working group proposed recommendations for managing allergic bronchopulmonary aspergillosis (ABPA) a decade ago. There is a need to update these recommendations due to advances in diagnostics and therapeutics.

METHODS

An international expert group was convened to develop guidelines for managing ABPA (caused by Aspergillus spp.) and allergic bronchopulmonary mycosis (ABPM; caused by fungi other than Aspergillus spp.) in adults and children using a modified Delphi method (two online rounds and one in-person meeting). We defined consensus as ≥70% agreement or disagreement. The terms "recommend" and "suggest" are used when the consensus was ≥70% and <70%, respectively.

RESULTS

We recommend screening for A. fumigatus sensitisation using fungus-specific IgE in all newly diagnosed asthmatic adults at tertiary care but only difficult-to-treat asthmatic children. We recommend diagnosing ABPA in those with predisposing conditions or compatible clinico-radiological presentation, with a mandatory demonstration of fungal sensitisation and serum total IgE ≥500 IU·mL-1 and two of the following: fungal-specific IgG, peripheral blood eosinophilia or suggestive imaging. ABPM is considered in those with an ABPA-like presentation but normal A. fumigatus-IgE. Additionally, diagnosing ABPM requires repeated growth of the causative fungus from sputum. We do not routinely recommend treating asymptomatic ABPA patients. We recommend oral prednisolone or itraconazole monotherapy for treating acute ABPA (newly diagnosed or exacerbation), with prednisolone and itraconazole combination only for treating recurrent ABPA exacerbations. We have devised an objective multidimensional criterion to assess treatment response.

CONCLUSION

We have framed consensus guidelines for diagnosing, classifying and treating ABPA/M for patient care and research.

Quality-of-Life Bronchiectasis Respiratory Symptom Scale Predicts the Risk of Exacerbations in Adults with Bronchiectasis: A Prospective Observational Study

Rationale: The relationship between symptoms, measured using a validated disease-specific questionnaire, and longitudinal exacerbation risk has not been demonstrated in bronchiectasis. Objectives: The aim of this study is to investigate whether baseline symptoms, assessed using the Quality-of-Life Bronchiectasis Respiratory Symptom Scale (QoL-B-RSS) and its individual component scores, could predict future exacerbation risk in patients with bronchiectasis. Methods: The study included 436 adults with bronchiectasis from three tertiary hospitals. Symptoms were measured using the QoL-B-RSS, with scores ranging from 0 to 100, where lower scores indicated more severe symptoms. We examined whether symptoms as continuous measures were associated with the risk of exacerbation over 12 months. The analysis was also repeated for individual components of the QoL-B-RSS score. Results: The baseline QoL-B-RSS score was associated with an increased risk of exacerbations (rate ratio, 1.25 for each 10-point decrease; 95% confidence interval [CI], 1.15-1.35; P < 0.001), hospitalizations (rate ratio, 1.24; 95% CI, 1.05-1.43; P = 0.02), and reduced time to the first exacerbation (hazard ratio, 1.12; 95% CI, 1.03-1.21; P = 0.01) over 12 months, even after adjusting for relevant confounders, including exacerbation history. The QoL-B-RSS score was comparable to exacerbation history in its association with future frequent exacerbations (defined as three or more exacerbations per year) and hospitalization (area under the curve, 0.86 vs. 0.84; P = 0.46; and area under the curve, 0.81 vs. 0.83; P = 0.41, respectively). Moreover, patients with more severe symptoms in the majority of individual components of the QoL-B-RSS were more likely to experience exacerbations. Conclusions: Symptoms can serve as useful indicators for identifying patients at increased risk of exacerbation in bronchiectasis. Beyond relying solely on exacerbation history, a comprehensive assessment of symptoms could facilitate timely and cost-effective implementation of interventions for exacerbation prevention.

Association between Clinical Characteristics and Microbiota in Bronchiectasis Patients Based on Metagenomic Next-Generation Sequencing Technology

This study aimed to investigate the disparities between metagenomic next-generation sequencing (mNGS) and conventional culture results in patients with bronchiectasis. Additionally, we sought to investigate the correlation between the clinical characteristics of patients and their microbiome profiles. The overarching goal was to enhance the effective management and treatment of bronchiectasis patients, providing a theoretical foundation for healthcare professionals. A retrospective survey was conducted on 67 bronchiectasis patients admitted to The First Hospital of Jiaxing from October 2019 to March 2023. Clinical baseline information, inflammatory indicators, and pathogen detection reports, including mNGS, conventional blood culture, bronchoalveolar lavage fluid (BALF) culture, and sputum culture results, were collected. By comparing the results of mNGS and conventional culture, the differences in pathogen detection rate and pathogen types were explored, and the diagnostic performance of mNGS compared to conventional culture was evaluated. Based on the various pathogens detected by mNGS, the association between clinical characteristics of bronchiectasis patients and mNGS microbiota results was analyzed. The number and types of pathogens detected by mNGS were significantly larger than those detected by conventional culture. The diagnostic efficacy of mNGS was significantly superior to conventional culture for all types of pathogens, particularly in viral detection (p < 0.01). Regarding pathogen detection rate, the bacteria with the highest detection rate were Pseudomonas aeruginosa (17/58) and Haemophilus influenzae (11/58); the fungus with the highest detection rate was Aspergillus fumigatus (10/21), and the virus with the highest detection rate was human herpes virus 4 (4/11). Differences were observed between the positive and negative groups for P. aeruginosa in terms of common scoring systems for bronchiectasis and whether the main symptom of bronchiectasis manifested as thick sputum (p < 0.05). Significant distinctions were also noted between the positive and negative groups for A. fumigatus regarding Reiff score, neutrophil percentage, bronchiectasis etiology, and alterations in treatment plans following mNGS results reporting (p < 0.05). Notably, 70% of patients with positive A. fumigatus infection opted to change their treatment plans. The correlation study between clinical characteristics of bronchiectasis patients and mNGS microbiological results revealed that bacteria, such as P. aeruginosa, and fungi, such as A. fumigatus, were associated with specific clinical features of patients. This underscored the significance of mNGS in guiding personalized treatment approaches. mNGS could identify multiple pathogens in different types of bronchiectasis samples and was a rapid and effective diagnostic tool for pathogen identification. Its use was recommended for diagnosing the causes of infections in bronchiectasis patients.

Long-term risks of respiratory diseases in patients infected with SARS-CoV-2: a longitudinal, population-based cohort study

Background

In the post-pandemic era, growing apprehension exists regarding the potential sequelae of COVID-19. However, the risks of respiratory diseases following SARS-CoV-2 infection have not been comprehensively understood. This study aimed to investigate whether COVID-19 increases the long-term risk of respiratory illness in patients with COVID-19.

Methods

In this longitudinal, population-based cohort study, we built three distinct cohorts age 37-73 years using the UK Biobank database; a COVID-19 group diagnosed in medical records between January 30th, 2020 and October 30th, 2022, and two control groups, a contemporary control group and a historical control group, with cutoff dates of October 30th, 2022 and October 30th, 2019, respectively. The follow-up period of all three groups was 2.7 years (the median (IQR) follow-up time was 0.8 years). Respiratory outcomes diagnosed in medical records included common chronic pulmonary diseases (asthma, bronchiectasis, chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD), pulmonary vascular disease (PVD), and lung cancer. For the data analysis, we calculated hazard ratios (HRs) along with their 95% CIs using Cox regression models, following the application of inverse probability weights (IPTW).

Findings

A total of 3 cohorts were included in this study; 112,311 individuals in the COVID-19 group with a mean age (±SDs) of 56.2 (8.1) years, 359,671 in the contemporary control group, and 370,979 in the historical control group. Compared with the contemporary control group, those infected with SARS-CoV-2 exhibited elevated risks for developing respiratory diseases. This includes asthma, with a HR of 1.49 and a 95% CI 1.28-1.74; bronchiectasis (1.30; 1.06-1.61); COPD (1.59; 1.41-1.81); ILD (1.81; 1.38-2.21); PVD (1.59; 1.39-1.82); and lung cancer (1.39; 1.13-1.71). With the severity of the acute phase of COVID-19, the risk of pre-described respiratory outcomes increases progressively. Besides, during the 24-months follow-up, we observed an increasing trend in the risks of asthma and bronchiectasis over time. Additionally, the HR of lung cancer for 0-6 month follow-up was 3.07 (CI 1.73-5.44), and the association of lung cancer with COVID-19 disease disappeared at 6-12 month follow-up (1.06; 0.43-2.64) and at 12-24 months (1.02; 0.45-2.34). Compared to those with one SARS-CoV-2 infection, reinfected patients were at a higher risk of asthma (3.0; 1.32-6.84), COPD (3.07; 1.42-6.65), ILD (3.61; 1.11-11.8), and lung cancer (3.20; 1.59-6.45). Similar findings were noted when comparing with a historical cohort serving as a control group, including asthma (1.31; 1.13-1.52); bronchiectasis (1.53; 1.23-1.89); COPD (1.41; 1.24-1.59); ILD (2.53; 2.05-3.13); PVD (2.30; 1.98-2.66); and lung cancer (2.23; 1.78-2.79).

Interpretation

Our research suggests that patients with COVID-19 may have an increased risk of developing respiratory diseases, and the risk increases with the severity of infection and reinfection. Even during the 24-month follow-up, the risk of asthma and bronchiectasis continued to increase. Hence, implementing appropriate follow-up strategies for these individuals is crucial to monitor and manage potential long-term respiratory health issues. Additionally, the increased risk in lung cancer in the COVID-19 individuals was probably due to the diagnostic tests conducted and incidental diagnoses.

Funding

The National Natural Science Foundation of China of China Regional Innovation and Development Joint Foundation; National Natural Science Foundation of China; Program for High-level Foreign Expert Introduction of China; Natural Science Foundation for Distinguished Young Scholars of Guangdong Province; Guangdong Basic and Applied Basic Research Foundation; Climbing Program of Introduced Talents and High-level Hospital Construction Project of Guangdong Provincial People's Hospital; VA Clinical Merit and ASGE clinical research funds.

Sputum metagenomics of people with bronchiectasis

Background

The microbiota in the sputum of people with bronchiectasis has repeatedly been investigated in cohorts of different geographic origin, but so far has not been studied to the species level in comparison to control populations including healthy adults and smokers without lung disease.

Methods

The microbial metagenome from sputa of 101 European Bronchiectasis Registry (EMBARC) study participants was examined by using whole-genome shotgun sequencing.

Results

Our analysis of the metagenome of people with bronchiectasis revealed four clusters characterised by a predominance of Haemophilus influenzae, Pseudomonas aeruginosa or polymicrobial communities with varying compositions of nonpathogenic commensals and opportunistic pathogens. The metagenomes of the severely affected patients showed individual profiles characterised by low alpha diversity. Importantly, nearly 50% of patients with severe disease were grouped in a cluster characterised by commensals. Comparisons with the sputum metagenomes of healthy smokers and healthy nonsmokers revealed a gradient of depletion of taxa in bronchiectasis, most often Neisseria subflava, Fusobacterium periodonticum and Eubacterium sulci.

Conclusion

The gradient of depletion of commensal taxa found in healthy airways is a key feature of bronchiectasis associated with disease severity.

Targeting respiratory microbiomes in COPD and bronchiectasis

INTRODUCTION

This review summarizes our current understanding of the respiratory microbiome in COPD and Bronchiectasis. We explore the interplay between microbial communities, host immune responses, disease pathology, and treatment outcomes.

AREAS COVERED

We detail the dynamics of the airway microbiome, its influence on chronic respiratory diseases, and analytical challenges. Relevant articles from PubMed and Medline (January 2010-March 2024) were retrieved and summarized. We examine clinical correlations of the microbiome in COPD and bronchiectasis, assessing how current therapies impact upon it. The potential of emerging immunotherapies, antiinflammatories and antimicrobial strategies is discussed, with focus on the pivotal role of commensal taxa in maintaining respiratory health and the promising avenue of microbiome remodeling for disease management.

EXPERT OPINION

Given the heterogeneity in microbiome composition and its pivotal role in disease development and progression, a shift toward microbiome-directed therapeutics is appealing. This transition, from traditional 'pathogencentric' diagnostic and treatment modalities to those acknowledging the microbiome, can be enabled by evolving crossdisciplinary platforms which have the potential to accelerate microbiome-based interventions into routine clinical practice. Bridging the gap between comprehensive microbiome analysis and clinical application, however, remains challenging, necessitating continued innovation in research, diagnostics, trials, and therapeutic development pipelines.

Pulmonary function outcomes after tuberculosis treatment in children: a systematic review and meta-analysis

BACKGROUND

Despite tuberculosis (TB) being a curable disease, current guidelines fail to account for the long-term outcomes of post-tuberculosis lung disease-a cause of global morbidity despite successful completion of effective treatment. Our systematic review aimed to synthesise the available evidence on the lung function outcomes of childhood pulmonary tuberculosis (PTB).

METHODS

PubMed, ISI Web of Science, Cochrane Library and ProQuest databases were searched for English-only studies without time restriction (latest search date 22 March 2023). Inclusion criteria were (1) patients who had TB with pulmonary involvement at age ≤18 years; (2) pulmonary function tests (PFTs) performed on patients after treatment completion; and (3) observational studies, including cohort and cross-sectional studies. We adhered to the recommendations of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

From 8040 records, 5 studies were included (involving n=567 children), with spirometry measures from 4 studies included in the meta-analyses. The effect sizes of childhood TB on forced expiratory volume in the first second and forced vital capacity z-scores were estimated to be -1.53 (95% CI -2.65, -0.41; p=0.007) and -1.93 (95% CI -3.35, -0.50; p=0.008), respectively.

DISCUSSION

The small number of included studies reflects this under-researched area, relative to the global burden of TB. Nevertheless, as childhood PTB impacts future lung function, PFTs (such as spirometry) should be considered a routine test when evaluating the long-term lung health of children beyond their completion of TB treatment. PROSPERO registration number CRD42021250172.

Bronchiectasis in renal transplant patients: a cross-sectional study

BACKGROUND

Bronchiectasis is a chronic airway disease characterized by permanent and irreversible abnormal dilatation of bronchi. Several studies have reported the development of bronchiectasis after renal transplantation (RT), but no prospective study specifically assessed bronchiectasis in this population. This study aimed to compare features of patients with bronchiectasis associated with RT to those with idiopathic bronchiectasis.

METHODS

Nineteen patients with bronchiectasis associated with RT (RT-B group) and 23 patients with idiopathic bronchiectasis (IB group) were prospectively included in this monocentric cross-sectional study. All patients underwent clinical, functional, laboratory, and CT scan assessments. Sputum was collected from 25 patients (n = 11 with RT-B and n = 14 with IB) and airway microbiota was analyzed using an extended microbiological culture.

RESULTS

Dyspnea (≥ 2 on mMRC scale), number of exacerbations, pulmonary function tests, total bronchiectasis score, severity and prognosis scores (FACED and E-FACED), and quality of life scores (SGRQ and MOS SF-36) were similar in the RT-B and IB groups. By contrast, chronic cough was less frequent in the RT-B group than in the IB group (68% vs. 96%, p = 0.03). The prevalence and diversity of the airway microbiota in sputum were similar in the two groups.

CONCLUSION

Clinical, functional, thoracic CT scan, and microbiological characteristics of bronchiectasis are overall similar in patients with IB and RT-B. These results highlight that in RT patients, chronic respiratory symptoms and/or airway infections should lead to consider the diagnosis of bronchiectasis. Further studies are required to better characterize the pathophysiology of RT-B including airway microbiota, its incidence, and impact on therapeutic management.

Applying the treatable traits approach in bronchiectasis-A scoping review of traits, measurements and treatments implemented by allied health professionals and nurses

BACKGROUND

Using treatable traits as a management approach in bronchiectasis involves determining identifiable, clinically relevant, measurable and treatable problems to develop a management strategy in collaboration with the patient.

OBJECTIVE

To identify new treatable traits not previously reported in the literature and treatment strategies for new and existing traits that could be implemented in an outpatient clinic or community setting by an allied health professional or nurse in adults with bronchiectasis.

METHODS

A scoping review was conducted with searches of MEDLINE, CINAHL, AMED, Embase, Cochrane Central Register of Controlled Trials and PsycInfo. The search yielded 9963 articles with 255 articles proceeding to full text review and 114 articles included for data extraction.

RESULTS

Sixteen new traits were identified, including fatigue (number of studies with new trait (n) = 13), physical inactivity (n = 13), reduced peripheral muscle power and/or strength (n = 12), respiratory muscle weakness (n = 9) and sedentarism (n = 6). The main treatment strategies for new and existing traits were airway clearance therapy (number of citations (n) = 86), pulmonary rehabilitation (n = 58), inspiratory muscle training (n = 20) and nebulised saline (n = 12).

CONCLUSION

This review identifies several new traits in bronchiectasis and highlights the common treatments for new and existing traits that can be implemented in a treatable traits approach in an outpatient clinic or community setting by an allied health professional or nurse.

Cystic Fibrosis Carrier States Are Associated With More Severe Cases of Bronchiectasis

Background

People with cystic fibrosis (CF) are at increased risk for bronchiectasis, and several reports suggest that CF carriers may also be at higher risk for developing bronchiectasis. The purpose of this study was to determine if CF carriers are at risk for more severe courses or complications of bronchiectasis.

Methods

Using MarketScan data (2001-2021), we built a cohort consisting of 105 CF carriers with bronchiectasis and 300 083 controls with bronchiectasis but without a CF carrier diagnosis. We evaluated if CF carriers were more likely to be hospitalized for bronchiectasis. In addition, we examined if CF carriers were more likely to be infected with Pseudomonas aeruginosa or nontuberculous mycobacteria (NTM) or to have filled more antibiotic prescriptions. We considered regression models for incident and rate outcomes that controlled for age, sex, smoking status, and comorbidities.

Results

The odds of hospitalization were almost 2.4 times higher (95% CI, 1.116-5.255) for CF carriers with bronchiectasis when compared with non-CF carriers with bronchiectasis. The estimated odds of being diagnosed with a Pseudomonas infection for CF carriers vs noncarriers was about 4.2 times higher (95% CI, 2.417-7.551) and 5.4 times higher (95% CI, 3.398-8.804) for being diagnosed with NTM. The rate of distinct antibiotic fill dates was estimated to be 2 times higher for carriers as compared with controls (95% CI, 1.735-2.333), and the rate ratio for the total number of days of antibiotics supplied was estimated as 2.8 (95% CI, 2.290-3.442).

Conclusions

CF carriers with bronchiectasis required more hospitalizations and more frequent administration of antibiotics as compared with noncarriers. Given that CF carriers were also more likely to be diagnosed with Pseudomonas and NTM infections, CF carriers with bronchiectasis may have a phenotype more resembling CF-related bronchiectasis than non-CF bronchiectasis.

Endotypes of Paediatric Cough-Do They Exist and Finding New Techniques to Improve Clinical Outcomes

Chronic cough is a common symptom of many childhood lung conditions. Given the phenotypic heterogeneity of chronic cough, better characterization through endotyping is required to provide diagnostic certainty, precision therapies and to identify pathobiological mechanisms. This review summarizes recent endotype discoveries in airway diseases, particularly in relation to children, and describes the multi-omic approaches that are required to define endotypes. Potential biospecimens that may contribute to endotype and biomarker discoveries are also discussed. Identifying endotypes of chronic cough can likely provide personalized medicine and contribute to improved clinical outcomes for children.

Impact of Pseudomonas aeruginosa on resource utilization and costs in patients with exacerbated non-cystic fibrosis bronchiectasis

AIMS

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic progressive respiratory disorder occurring at a rate ranging from 4.2 to 278.1 cases per 100,000 persons, depending on age, in the United States. For many patients with NCFB, the presence of Pseudomonas aeruginosa (PA) makes treatment more complicated and typically has worse outcomes. Management of NCFB can be challenging, warranting a better understanding of the burden of illness for NCFB, treatments applied, healthcare resources used, and subsequent treatment costs. Comparing patients diagnosed with exacerbated NCFB, with or without PA on antibiotic utilization, treatments, and healthcare resources utilization and costs was the purpose of this study.

MATERIALS AND METHODS

This was a retrospective cohort study of commercial claims from IQVIA's PharMetrics Plus database (January 1,2006-December 31, 2020). Study patients with a diagnosis of NCFB were stratified into two groups based on the presence or absence of PA, then followed to identify demographic characteristics, comorbid conditions, antibiotic treatment regimen prescribed, healthcare resources utilized, and costs of care.

RESULTS

The results showed that patients with exacerbated NCFB who were PA+ had significantly more oral antibiotic fills per patient per year, more inpatient admissions with a longer length of stay, and more outpatient encounters than those who were PA-. For costs, PA+ patients also had significantly greater total healthcare costs per patient when compared to those who were PA-.

CONCLUSION

Exacerbated NCFB with PA+ was associated with increased antibiotic usage, greater resource utilization, and increased costs. The major contributor to the cost differences was the use of inpatient services. Treatment strategies aimed at reducing the need for inpatient treatment could lessen the disparities observed in patients with NCFB.

A core outcome set for bronchiectasis in children and adolescents for use in clinical research: an international consensus study

Improving the treatment of non-cystic fibrosis bronchiectasis in children and adolescents requires high-quality research with outcomes that meet study objectives and are meaningful for patients and their parents and caregivers. In the absence of systematic reviews or agreement on the health outcomes that should be measured in paediatric bronchiectasis, we established an international, multidisciplinary panel of experts to develop a core outcome set (COS) that incorporates patient and parent perspectives. We undertook a systematic review from which a list of 21 outcomes was constructed; these outcomes were used to inform the development of separate surveys for ranking by parents and patients and by health-care professionals. 562 participants (201 parents and patients from 17 countries, 361 health-care professionals from 58 countries) completed the surveys. Following two consensus meetings, agreement was reached on a ten-item COS with five outcomes that were deemed to be essential: quality of life, symptoms, exacerbation frequency, non-scheduled health-care visits, and hospitalisations. Use of this international consensus-based COS will ensure that studies have consistent, patient-focused outcomes, facilitating research worldwide and, in turn, the development of evidence-based guidelines for improved clinical care and outcomes. Further research is needed to develop validated, accessible measurement instruments for several of the outcomes in this COS.