Trend from 2001 to 2015 in the prevalence of bronchiectasis among patients hospitalized for asthma and effect of bronchiectasis on the in-hospital mortality

Sputum metagenomics reveals a multidrug resistant Pseudomonas-dominant severe asthma phenotype in an Asian population

BACKGROUND AND OBJECTIVE

While the lung microbiome in severe asthma has been studied, work has employed targeted amplicon-based sequencing approaches without functional assessment with none focused on multi-ethnic Asian populations. Here we investigate the clinical relevance of microbial phenotypes of severe asthma in Asians using metagenomics.

METHODS

Prospective assessment of clinical, radiological, and immunological measures were performed in a multi-ethnic Asian severe asthma cohort (N = 70) recruited across two centres in Singapore. Sputum was subjected to shotgun metagenomic sequencing and patients followed up for a 2-year period. Metagenomic assessment of sputum microbiomes, resistomes and virulomes were related to clinical outcomes.

RESULTS

The lung microbiome in a multi-ethnic Asian cohort with severe asthma demonstrates an increased abundance of Pseudomonas species. Unsupervised clustering of sputum metagenomes identified two patient clusters: C1 (n = 52) characterized by upper airway commensals and C2 (n = 18) dominated by established respiratory pathogens including M. catarrhalis, S. aureus and most significantly P. aeruginosa. C2 patients demonstrated a significantly increased exacerbation frequency on 2-year follow up and an antimicrobial resistome characterized by multidrug resistance. Virulomes appear indistinguishable between severe asthmatics with or without co-existing bronchiectasis, and C2 patients exhibit increased gene expression related to biofilm formation, effector delivery systems and microbial motility. Independent comparison of the C2 cluster to a non-asthmatic bronchiectasis cohort demonstrates analogous airway microbial virulence patterns.

CONCLUSION

Sputum metagenomics demonstrates a multidrug-resistant Pseudomonas-dominant severe asthma phenotype in Asians, characterized by poor clinical outcome including increased exacerbations which is independent of co-existing bronchiectasis.

The Phenotypes of Asthma-Bronchiectasis Overlap: Clinical Characteristics and Outcomes

BACKGROUND

Asthma-bronchiectasis overlap (ABO) encompasses heterogeneous manifestations, which may predict distinct clinical outcomes. We sought to identify the clinical phenotypes of ABO and compare them to asthma alone or bronchiectasis alone.

METHODS

In this retrospective cohort study, we extracted electronic medical records from 292 inpatients with ABO, 901 inpatients with asthma alone, and 1,192 inpatients with bronchiectasis alone who were hospitalized between 2015 and 2020. We phenotyped ABO using 2-step unsupervised clustering analysis by using an independent cohort (n = 76).

RESULTS

Compared to asthma or bronchiectasis alone, ABO exhibited greater disease severity and worse clinical outcomes. We identified 3 ABO phenotypes: asthma-dominant ABO (ABO-A, n = 100) with more prominent asthma symptoms; bronchiectasis-dominant ABO (ABO-B, n = 89) with more pronounced features of bronchiectasis; and co-existence of asthma and severe bronchiectasis (ABO-S, n = 103) with worse clinical outcomes. Compared to ABO-B, both ABO-A and ABO-S were associated with significantly higher blood neutrophil ratios (55.8% vs. 59.1% vs. 64.4%, P < 0.001), poorer lung function (FEV1% predicted: 79.1% vs. 67.5% vs. 50.1%, P < 0.001), longer hospital stay (6.0 vs. 7.0 vs. 7.0 days, P = 0.004), and higher risks of hospitalization within the next 2 years (ABO-A: hazards ratio [HR], 3.76, 95% confidence interval [CI], 1.12-12.62, P = 0.032; ABO-S: HR, 4.05, 95% CI, 1.14-14.36, P = 0.031).

CONCLUSIONS

The radiologic severity of bronchiectasis and the use of systemic corticosteroids can identify the clinical phenotypes of ABO. The heterogeneity of clinical manifestations may help formulate personalized management strategies and predict the prognosis of ABO.

Asthma and respiratory comorbidities

Asthma is a common respiratory condition with various phenotypes, nonspecific symptoms, and variable clinical course. The occurrence of other respiratory conditions with asthma, or respiratory comorbidities (RCs), is not unusual. A literature search of PubMed was performed for asthma and a variety of respiratory comorbidities for the years 2019 to 2024. The 5 conditions with the largest number of references, other than rhinitis and rhinosinusitis (addressed elsewhere), or that are the most problematic in the authors' clinical experience, are summarized. Others are briefly discussed. The diagnosis and treatment of both asthma and RCs are complicated by the overlap of symptoms and signs. Recognizing RCs is especially problematic in adult-onset, non-type 2 asthma because there are no biomarkers to assist in confirming non-type 2 asthma. Treatment decisions in subjects with suspected asthma and RCs are complicated by the potential similarities between the symptoms or signs of the RC and asthma, the absence of a sine quo non for the diagnosis of asthma, the likelihood that many RCs improve with systemic corticosteroid therapy, and the possibility that manifestations of the RCs are misattributed to asthma or vice versa. Recognition of RCs is critical to the effective management of asthma, particularly severe or difficult-to-treat asthma.

[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.

Does asthma-bronchiectasis overlap syndrome (ABOS) really exist?

OBJECTIVE

To analyze the relationship between asthma and bronchiectasis, as well as the necessary conditions that this connection must meet for this group of patients to be considered a special phenotype.

DATA SOURCES

We performed a PubMed search using the MeSH terms "asthma" and "bronchiectasis." The literature research was limited to clinical trials, meta-analyses, randomized controlled trials, cohort studies, and systematic reviews, involving adult patients, published until November 30th, 2022.

STUDY SELECTIONS

Selected papers were initially evaluated by the Authors, to assess their eligibility in contributing to the statements.

RESULTS

The prevalence of bronchiectasis is higher than expected in patients with asthma, particularly in those with more severe disease, and in some patients, between 1.4% and 7% of them, asthma alone could be the cause of bronchiectasis. Both diseases share etiopathogenic mechanisms, such as neutrophilic and eosinophilic inflammation, altered airway microbiota, mucus hypersecretion, allergen sensitization, immune dysfunction, altered microRNA, dysfunctional neutrophilic activity, and variants of the HLA system. Besides that, they also share comorbidities, such as gastroesophageal reflux disease and psychiatric illnesses. The clinical presentation of asthma is very similar to patients with bronchiectasis, which could cause mistakes with diagnoses and delays in being prescribed the correct treatment. The coexistence of asthma and bronchiectasis also poses difficulties for the therapeutic focus.

CONCLUSIONS

The evidence available seems to support that the asthma-bronchiectasis phenotype really exists although longitudinal studies which consistently demonstrate that asthma is the cause of bronchiectasis are still lacking.

Benralizumab Effectiveness in Severe Eosinophilic Asthma with Co-Presence of Bronchiectasis: A Real-World Multicentre Observational Study

Introduction: The co-presence of bronchiectasis (BE) in severe eosinophilic asthma (SEA) is common. Data about the effectiveness of benralizumab in patients with SEA and BE (SEA + BE) are lacking. Aim: The aim of this study was to evaluate the effectiveness of benralizumab and remission rates in patients with SEA compared to SEA + BE, also according to BE severity. Methods: We conducted a multicentre observational study, including patients with SEA who underwent chest high-resolution computed tomography at baseline. The Bronchiectasis Severity Index (BSI) was used to assess BE severity. Clinical and functional characteristics were collected at baseline and after 6 and 12 months of treatment. Results: We included 74 patients with SEA treated with benralizumab, of which 35 (47.2%) showed the co-presence of bronchiectasis (SEA + BE) with a median BSI of 9 (7-11). Overall, benralizumab significantly improved the annual exacerbation rate (p < 0.0001), oral corticosteroids (OCS) consumption (p < 0.0001) and lung function (p < 0.01). After 12 months, significant differences were found between SEA and SEA + BE cohorts in the number of exacerbation-free patients [64.1% vs. 20%, OR 0.14 (95% CI 0.05-0.40), p < 0.0001], the proportion of OCS withdrawal [-92.6% vs. -48.6, p = 0.0003], and the daily dose of OCS [-5 mg (0 to -12.5) vs. -12.5 mg (-7.5 to -20), p = 0.0112]. Remission (zero exacerbations + zero OCS) was achieved more frequently in the SEA cohort [66.7% vs. 14.3%, OR 0.08 (95% CI 0.03-0.27), p < 0.0001]. Changes in FEV₁% and FEF_25-75% were inversely correlated with BSI (r = -0.36, p = 0.0448 and r = -0.41, p = 0.0191, respectively). Conclusions: These data suggest that benralizumab exerts beneficial effects in SEA with or without BE, although the former achieved less OCS sparing and fewer respiratory-function improvements.

Additive effects of coexisting respiratory comorbidities on overall or respiratory mortality in patients with asthma: a national cohort study

Asthmatic patients are generally considered to have an increased risk of mortality compared with subjects without asthma. However, this issue has been less evaluated using nationally representative data. Moreover, it is unclear whether respiratory comorbidities other than chronic obstructive pulmonary disease (COPD) are associated with increased mortality in asthmatic patients compared with subjects without. Using a nationally representative sample database, we performed a retrospective cohort study of patients with asthma and age-sex-matched control cohort. We estimated the hazard ratio (HR) and stratified the asthma cohort based on respiratory comorbidities. During a median 8.9-year follow-up, the overall mortality rate was higher in the asthma cohort than in the control cohort (p < 0.001). The hazard ratio (HR) for overall mortality in the asthma cohort compared with the control cohort was 1.13. The effects of asthma on overall mortality were more evident in males, patients under medical aid, and subjects with COPD. Respiratory comorbidities were significantly associated with increased risk of overall mortality in asthmatic patients compared with controls (adjusted HRs; 1.48 for COPD, 1.40 for bronchiectasis, 4.08 for lung cancer, and 1.59 for pneumonia). While asthma and lung cancer showed an additive effect only on overall mortality, asthma and other respiratory comorbidities (COPD, pneumonia, and bronchiectasis) had additive effects only on respiratory mortality. Patients with asthma had a higher overall mortality rate compared with subjects without asthma. Respiratory comorbidities showed an additive effect on overall or respiratory mortality in patients with asthma.

Increasing prevalence and burden of bronchiectasis in urban Chinese adults, 2013-2017: a nationwide population-based cohort study

Background

While the prevalence and disease burden of bronchiectasis are increasing, data in the world’s largest population are lacking. We aimed to investigate the prevalence and disease burden of bronchiectasis in Chinese adults.

Methods

We conducted a population-based study using data between 2013 and 2017 from the national databases of Urban Employee Basic Medical Insurance and Urban Resident Basic Medical Insurance in China. Data from over 380 million patients aged 18 years and older during the study period were analyzed, and a total of 383,926 bronchiectasis patients were identified. Primary outcomes included the age- and sex-specific prevalence of bronchiectasis. Annual visits and hospitalizations, as well as annual costs were also calculated.

Results

The prevalence of bronchiectasis in Chinese adults increased 2.31-fold, from 75.48 (62.26, 88.69) per 100,000 in 2013 to 174.45 (137.02, 211.88) per 100,000 in 2017. The increase was more remarkable for patients aged over 50 years in both genders. The per-capita total cost and hospitalization cost of patients with bronchiectasis increased 2.18-fold and 1.83-fold from 2013 to 2017, respectively, mostly driven by non-bronchiectasis costs. The average annual hospitalization ranged from 1.20 to 1.24 times during the 5 years.

Conclusion

The prevalence and disease burden of bronchiectasis in Chinese urban adults ≥ 18 years had increased significantly between 2013 and 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02023-8.

Asthma and Comorbid Conditions-Pulmonary Comorbidity

Pulmonary comorbidities can increase disease severity and health care costs associated with asthma management. Vocal cord dysfunction/inducible laryngeal obstruction is a common comorbidity that results from intermittent laryngeal obstruction. Patients describe distinct episodes of dyspnea that do not respond to bronchodilators. Inspiratory stridor is common. The gold standard diagnostic testing strategy is continuous laryngoscopy performed during exercise or irritant challenges. Dysfunctional breathing (DB) is an overarching term that describes conditions with a chronic change in the pattern of breathing that results in pulmonary and extrapulmonary symptoms. The prevalence of DB in asthma is up to 30%, and breathing retraining can improve symptoms and quality of life in people with DB and asthma. Asthma-chronic obstructive pulmonary disease overlap (ACO) refers to both asthmatics who develop fixed airflow obstruction after a history of exposure to smoke or biomass and patients with chronic obstructive pulmonary disease who have "asthmatic features" such as a large bronchodilator response, elevated levels of serum IgE, or peripheral eosinophil counts ≥300 per μL. Triple inhaler therapy with inhaled corticosteroid/long-acting beta-agonist/long-acting muscarinic should be considered in people with ACO and severe symptoms or frequent exacerbations. The clinical expression of bronchiectasis involves persistent mucus hypersecretion, recurrent exacerbations of infective bronchitis, incompletely reversible airflow obstruction, and lung fibrosis and can occur in up to 30% of adults with longstanding asthma. The treatable traits strategy is a useful model of care to manage the complexity and heterogeneity of asthma with pulmonary comorbidity.

Impact of Pseudomonas aeruginosa Infection on Patients with Chronic Inflammatory Airway Diseases

Pseudomonas aeruginosa (P. aeruginosa) is a ubiquitous and opportunistic microorganism and is considered one of the most significant pathogens that produce chronic colonization and infection of the lower respiratory tract, especially in people with chronic inflammatory airway diseases such as asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), and bronchiectasis. From a microbiological viewpoint, the presence and persistence of P. aeruginosa over time are characterized by adaptation within the host that precludes any rapid, devastating injury to the host. Moreover, this microorganism usually develops antibiotic resistance, which is accelerated in chronic infections especially in those situations where the frequent use of antimicrobials facilitates the selection of “hypermutator P. aeruginosa strain”. This phenomenon has been observed in people with bronchiectasis, CF, and the “exacerbator” COPD phenotype. From a clinical point of view, a chronic bronchial infection of P. aeruginosa has been related to more severity and poor prognosis in people with CF, bronchiectasis, and probably in COPD, but little is known on the effect of this microorganism infection in people with asthma. The relationship between the impact and treatment of P. aeruginosa infection in people with airway diseases emerges as an important future challenge and it is the most important objective of this review.