Suspecting non-cystic fibrosis bronchiectasis: What the busy primary care clinician needs to know

Emerging strategies to target virulence in Pseudomonas aeruginosa respiratory infections

Pseudomonas aeruginosa is an opportunistic pathogen that is responsible for infections in people living with chronic respiratory conditions, such as cystic fibrosis (CF) and non-CF bronchiectasis (NCFB). Traditionally, in people with chronic respiratory disorders, P. aeruginosa infection has been managed with a combination of inhaled and intravenous antibiotic therapies. However, due in part to the prolonged use of antibiotics in these people, the emergence of multi-drug resistant P. aeruginosa strains is a growing concern. The development of anti-virulence therapeutics may provide a new means of treating P. aeruginosa lung infections whilst also combatting the AMR crisis, as these agents are presumed to exert reduced pressure for the emergence of drug resistance as compared to antibiotics. However, the pipeline for developing anti-virulence therapeutics is poorly defined, and it is currently unclear as to whether in vivo and in vitro models effectively replicate the complex pulmonary environment sufficiently to enable development and testing of such therapies for future clinical use. Here, we discuss potential targets for P. aeruginosa anti-virulence therapeutics and the effectiveness of the current models used to study them. Focus is given to the difficulty of replicating the virulence gene expression patterns of P. aeruginosa in the CF and NCFB lung under laboratory conditions and to the challenges this poses for anti-virulence therapeutic development.

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.

Insights Into Cystic Fibrosis Gene Mutation Frequency, Clinical Findings, and Complications Among Pakistani Patients

Background Cystic fibrosis (CF) is a genetic disorder with diverse symptoms. Understanding its genetic basis and prevalence is crucial for effective management and treatment. Objective The study aimed to provide comprehensive insights into the frequency of CF gene mutations, clinical presentations, and complications among the Pakistani population. Methodology A cohort comprising 892 patients, ranging in age from 18 to more than 40 years, was selected on the basis of clinical and genetic criteria for the diagnosis of CF. Polymerase chain reaction (PCR) was used to look for 34 variants in the CFTR gene in blood samples. Statistical analysis, which included figuring out the number of mutations, the average age of diagnosis, and the genetic diversity of the samples, was performed to analyze the percentage of patients with specific mutations, offering insights into the genetic diversity. Results In our comprehensive analysis of 892 patient samples, 77.47% (n=691) displayed consanguinity, indicating a family history. The prevailing symptoms included chronic cough (88.67%; n=791), recurrent respiratory infections (76.68%; n=684), and fatigue (73.76%; n=658). The major complications comprised pulmonary infections (22%; n=197), cystic fibrosis-related diabetes (21%; n=187), and malabsorption (20%: n=178). A paired t-test revealed a mean difference of 5.750 with a standard deviation of 9.147, a 95% confidence interval from -0.061 to 11.561, a t-value of 2.178 with 11 degrees of freedom, and a two-tailed p-value of 0.052, suggesting a potential trend towards significance. Nevertheless, the asymptotic significance values of 1.000 and 0.998 for both groups indicate no significant difference. Furthermore, the study identified 12 cystic fibrosis gene mutations, with F508del and N1303K being the most prevalent. Conclusion This research revealed significant consanguinity, confirmed typical CF symptoms, and identified common complications and prevalent CFTR gene mutations (with F508del and N1303K being the most common), providing insights for genetic guidance and treatment in the Pakistani community.

Epithelial-Mesenchymal Transition Mechanisms in Chronic Airway Diseases: A Common Process to Target?

Epithelial-to-mesenchymal transition (EMT) is a reversible process, in which epithelial cells lose their epithelial traits and acquire a mesenchymal phenotype. This transformation has been described in different lung diseases, such as lung cancer, interstitial lung diseases, asthma, chronic obstructive pulmonary disease and other muco-obstructive lung diseases, such as cystic fibrosis and non-cystic fibrosis bronchiectasis. The exaggerated chronic inflammation typical of these pulmonary diseases can induce molecular reprogramming with subsequent self-sustaining aberrant and excessive profibrotic tissue repair. Over time this process leads to structural changes with progressive organ dysfunction and lung function impairment. Although having common signalling pathways, specific triggers and regulation mechanisms might be present in each disease. This review aims to describe the various mechanisms associated with fibrotic changes and airway remodelling involved in chronic airway diseases. Having better knowledge of the mechanisms underlying the EMT process may help us to identify specific targets and thus lead to the development of novel therapeutic strategies to prevent or limit the onset of irreversible structural changes.

Profile of Clinical and Analytical Parameters in Bronchiectasis Patients during the COVID-19 Pandemic: A One-Year Follow-Up Pilot Study

Whether the COVID-19 pandemic may have modified the clinical planning and course in bronchiectasis patients remains to be fully elucidated. We hypothesized that the COVID-19 pandemic may have influenced the management and clinical outcomes of bronchiectasis patients who were followed up for 12 months. In bronchiectasis patients (n = 30, 23 females, 66 years), lung function testing, disease severity [FEV₁, age, colonization, radiological extension, dyspnea (FACED), exacerbation (EFACED)] and dyspnea scores, exacerbation numbers and hospitalizations, body composition, sputum microbiology, and blood analytical biomarkers were determined at baseline and after a one-year follow-up. Compared to baseline (n = 27, three patients dropped out), in bronchiectasis patients, a significant increase in FACED and EFACED scores, number of exacerbations, and erythrocyte sedimentation rate (ESR) was observed, while FEV₁, ceruloplasmin, IgE, IgG, IgG aspergillus, IgM, and IgA significantly decreased. Patients presenting colonization by Pseudomonas aeruginosa (PA) remained unchanged (27%) during follow-up. In bronchiectasis patients, FEV₁ declined only after a one-year follow-up along with increased exacerbation numbers and disease severity scores, but not hospitalizations. However, a significant decrease in acute phase-reactants and immunoglobulins was observed at the one-year follow-up compared to baseline. Despite the relatively small cohort, the reported findings suggest that lung function impairment may not rely entirely on the patients’ inflammatory status.

Bronchiectasis and inhaled tobramycin: A literature review

BACKGROUND

Inhaled antibiotics have been incorporated into contemporary European and British guidelines for bronchiectasis, yet no inhaled antibiotics have been approved in the United States or Europe for the treatment of bronchiectasis not related to cystic fibrosis. Pseudomonas aeruginosa infection is common in patients with bronchiectasis, contributing to a cycle of progressive inflammation, exacerbations, and airway remodelling.

OBJECTIVE

The aim of the current study was to identify and evaluate published studies of inhaled tobramycin solution or powder in patients with bronchiectasis and P. aeruginosa infection not associated with cystic fibrosis.

METHODS

A literature review was conducted utilising the PubMed and Cochrane databases. Studies published in the English language that reported safety and/or efficacy outcomes of inhaled tobramycin either alone or in combination with other antibiotics were included.

RESULTS

Seven clinical trials published between 1999 and 2021 were identified that met inclusion criteria. Inhaled tobramycin therapy was effective in reducing P. aeruginosa microbial density in the sputum of patients with bronchiectasis. Several studies demonstrated favourable impacts on hospitalisations, number and severity of exacerbations, and symptoms. Other studies were underpowered for these clinical outcomes or were exploratory in nature. Although tobramycin was generally well tolerated, some evidence of treatment-associated wheezing was reported.

CONCLUSIONS

In patients with bronchiectasis and chronic P. aeruginosa infection, inhaled tobramycin was effective in reducing the density of bacteria in sputum, which may be associated with additional clinical benefits. Definitive phase 3 trials of inhaled tobramycin in patients with bronchiectasis are indicated to determine clinical efficacy and long-term safety.

Aspergillus-Associated Endophenotypes in Bronchiectasis

Bronchiectasis is a chronic condition of global relevance resulting in permanent and irreversible structural airway damage. Bacterial infection in bronchiectasis is well studied; however, recent molecular studies identify fungi as important pathogens, either independently or in association with bacteria. Aspergillus species are established fungal pathogens in cystic fibrosis and their role is now increasingly being recognized in noncystic fibrosis bronchiectasis. While the healthy airway is constantly exposed to ubiquitously present Aspergillus conidia in the environment, anatomically damaged airways appear more prone to colonization and subsequent infection by this fungal group. Aspergilli possess diverse immunopathological mechanistic capabilities and when coupled with innate immune defects in a susceptible host, such as that observed in bronchiectasis, it may promote a range of clinical manifestations including sensitization, allergic bronchopulmonary aspergillosis, Aspergillus bronchitis, and/or invasive aspergillosis. How such clinical states influence "endophenotypes" in bronchiectasis is therefore of importance, as each Aspergillus-associated disease state has overlapping features with bronchiectasis itself, and can evolve, depending on underlying host immunity from one type into another. Concurrent Aspergillus infection complicates the clinical course and exacerbations in bronchiectasis and therefore dedicated research to better understand the Aspergillus-host interaction in the bronchiectasis airway is now warranted.

Small Airway Disease and Emphysema Are Associated with Future Exacerbations in Smokers with CT-derived Bronchiectasis and COPD: Results from the COPDGene Cohort

Background Chronic obstructive pulmonary disease (COPD) and bronchiectasis can overlap and share pathologic features, such as small airway disease (SAD). Whether the presence of SAD and emphysema in smokers with CT-derived bronchiectasis is associated with exacerbations is unknown. Purpose To assess whether SAD and emphysema in smokers with CT-derived bronchiectasis are associated with future exacerbations. Materials and Methods SAD and emphysema were quantified using the parametric response map method in former and current heavy smokers with and without bronchiectasis at CT from the COPDGene Study (from July 2009 to July 2018). Exacerbations were prospectively assessed through biannual follow-up. An exacerbation was defined as an increase in or new onset of respiratory symptoms treated with antibiotics and/or corticosteroids. Severe exacerbations were defined as those that required hospitalization. The association of a high burden of SAD (≥15.6%) and high burden of emphysema (≥5%) at CT with exacerbations was assessed with generalized linear mixed models. Results Of 737 participants, 387 (median age, 64 years [interquartile range, 58-71 years]; 223 women) had CT-derived bronchiectasis. During a 9-year follow-up, after adjustment for age, sex, race, body mass index, current smoking status, pack-years, exacerbations before study entry, forced expiratory volume in 1 second, or FEV₁, and bronchiectasis severity CT score, high burden of SAD and high burden of emphysema were associated with a higher number of exacerbations per year (relative risk [RR], 1.89 [95% CI: 1.54, 2.33] and 1.37 [95% CI: 1.13, 1.66], respectively; P ≤ .001 for both). Results were comparable among participants with bronchiectasis meeting criteria for COPD (n = 197) (RR, 1.67 [95% CI: 1.23, 2.27] for high burden of SAD and 1.51 [95% CI: 1.20, 1.91] for high burden of emphysema; P ≤ .001 for both). Conclusion In smokers with CT-derived bronchiectasis and chronic obstructive pulmonary disease, structural damage to lung parenchyma and small airways was associated with a higher number of exacerbations per year. Clinical trial registration no. NCT00608764 © RSNA, 2021.

Paired CT Measures of Emphysema and Small Airways Disease and Lung Function and Exercise Capacity in Smokers with Radiographic Bronchiectasis

RATIONALE AND OBJECTIVES

Bronchiectasis (BE) is associated with chronic obstructive pulmonary disease (COPD), but emphysema and small airways disease, main pathologic features of COPD, have been sparsely studied in BE. We aimed to objectively assess those features in smokers with and without radiographic BE and examine its relationships to airflow obstruction and exercise capacity.

MATERIAL AND METHODS

We measured emphysema and small airways disease on paired inspiratory-expiratory computed tomography (CT) scans with the parametric response map (PRM^EMPH and PRM^SAD) method in 1184 smokers with and without radiographic BE. PRM^SAD and PRM^EMPH are expressed as the percentage of lung area. Clinical, spirometry, and exercise capacity data were measured with standardized methods. The differences in PRM^SAD and PRM^EMPH between subjects with and without radiographic BE were assessed using multivariable linear regression analysis, and their associations with FEV₁ and six-minute walk test (6MWT) were assessed with generalized linear models.

RESULTS

Out of 1184 subjects, 383 (32%) had radiographic BE. PRM^EMPH but not PRM^SAD was higher in subjects with radiographic BE than those without radiographic BE in adjusted models. Subjects with radiographic BE and PRM^EMPH (defined as ≥5% on paired CTs) had lower FEV₁ (least square mean, 1479 mL vs. 2350 mL p < 0.0001) and 6MWT (372 m vs. 426 m p = 0.0007) than those with radiographic BE alone in adjusted models.

CONCLUSION

Smokers with radiographic BE have an increased burden of emphysema on paired CTs, and those with radiographic BE and emphysema have lower airflow and exercise capacity.

Health-care utilization and expenditures among patients with comorbid bronchiectasis and chronic obstructive pulmonary disease in US clinical practice

Recent research suggests that bronchiectasis (BE) may be more common than previously believed and that comorbid chronic obstructive pulmonary disease (COPD) is widespread in this patient population. Little is known about the economic burden among patients with BE, and less is known about the burden among those with comorbid BE + COPD. A retrospective matched-cohort design and data from a US health-care claims repository were employed. From the source population comprising adults who had comprehensive medical/drug benefits for ≥1 day in 2013 (i.e. the referent year) and evidence of BE and/or COPD at any time from 2009 to 2013, patients with BE + COPD were age/sex-matched (1:1:1) to patients with BE only and patients with COPD only. For each matched subgroup, annualized levels of respiratory-related and all-cause health-care utilization and expenditures in 2013 were summarized. Source population included 679,679 patients; among those with BE (n = 31,027), 50% had comorbid COPD. Mean (95% CI) annual levels of respiratory-related utilization and expenditures among matched patients with BE + COPD (n = 11,685) were higher by 2.4–3.5 times versus patients with BE only and 2.0–2.5 times versus patients with COPD only: hospitalizations, 0.39 (0.37–0.41) versus 0.11 (0.09–0.12) and 0.16 (0.14–0.17); ambulatory encounters, 16.5 (16.1–16.9) versus 6.8 (6.6–7.0) and 8.2 (7.9–8.4); and total expenditures, US$15,685 (14,693–16,678) versus US$5605 (5059–6150) and US$6262 (5655–6868). Respiratory-related utilization and expenditures are high among patients with BE or COPD receiving medical care in US clinical practice and are especially high among those with comorbid BE + COPD receiving medical care, emphasizing the importance of identifying and treating this unique patient population. Funding for this research was provided by RespirTech to Policy Analysis Inc. (PAI).

Biofilm Formations in Pediatric Respiratory Tract Infection : Part 1: Biofilm Structure, Role of Innate Immunity in Protection Against and Response to Biofilm, Methods of Biofilm Detection, Pediatric Respiratory Tract Diseases Associated with Mucosal Biofilm Formation

PURPOSE OF REVIEW

Biofilm represents an organized structure of microorganisms within an extracellular matrix attached to a surface. While the importance of biofilm in prosthetic heart valve and catheter-related infections has been known since the 1980s, the role of mucosal biofilm in human disease pathogenesis has only recently been elucidated. It is now clear that mucosal biofilm is present in both healthy and pathologic states. The purpose of this review is to examine the role of mucosal biofilm in pediatric respiratory infections.

RECENT FINDINGS

Mucosal biofilm has been implicated in relationship to several pediatric respiratory infections, including tonsillitis, adenoiditis, otitis media with effusion, chronic rhinosinusitis, persistent endobronchial infection, and bronchiectasis. In these conditions, core pathogens are detected in the biofilm, biofilm organisms are often detected by molecular techniques when conventional cultures are negative, and biofilm presence is more extensive in relation to disease than in healthy tissues. In chronic rhinosinusitis, the presence of polymicrobial biofilm is also a predictor of poorer outcome following sinus surgery. Biofilm in the tonsillar and adenoidal compartments plays a distinct role in contributing to disease in the middle ear and sinuses. Key observations regarding the relevance of biofilm to pediatric respiratory infections include (1) the association between the presence of biofilm and persistent/recurrent and more severe disease in these tissues despite antibiotic treatment, (2) linkage between biofilm core pathogens and acute infections, and (3) interrelationship between biofilm presence in one tissue and persistent or recurrent infection in an adjacent tissue. A greater understanding of the significance of mucosal biofilm will undoubtedly emerge with the development of effective means of eradicating mucosal biofilm.

Pulmonary vascular pruning in smokers with bronchiectasis

There are few studies looking at the pulmonary circulation in subjects with bronchiectasis. We aimed to evaluate the intraparenchymal pulmonary vascular structure, using noncontrast chest computed tomography (CT), and its clinical implications in smokers with radiographic bronchiectasis. Visual bronchiectasis scoring and quantitative assessment of the intraparenchymal pulmonary vasculature were performed on CT scans from 486 smokers. Clinical, lung function and 6-min walk test (6MWT) data were also collected. The ratio of blood vessel volume in vessels <5 mm2 in cross-section (BV5) to total blood vessel volume (TBV) was used as measure of vascular pruning, with lower values indicating more pruning. Whole-lung and lobar BV5/TBV values were determined, and regression analyses were used to assess the differences in BV5/TBV between subjects with and without bronchiectasis. 155 (31.9%) smokers had bronchiectasis, which was, on average, mild in severity. Compared to subjects without bronchiectasis, those with lower-lobe bronchiectasis had greater vascular pruning in adjusted models. Among subjects with bronchiectasis, those with vascular pruning had lower forced expiratory volume in 1 s and 6MWT distance compared to those without vascular pruning. Smokers with mild radiographic bronchiectasis appear to have pruning of the distal pulmonary vasculature and this pruning is associated with measures of disease severity.

Health care experiences of mothers of children with bronchiectasis in Counties Manukau, Auckland, New Zealand

BACKGROUND

Bronchiectasis is a worsening public health problem in New Zealand. This study aimed to explore the health care experiences of mothers of children with bronchiectasis in the Counties Manukau District Health Board area of Auckland, New Zealand.

METHODS

Semi-structured interviews were undertaken with ten mothers of children with bronchiectasis. Data were analysed using thematic analysis.

RESULTS

Five themes emerged: 1) Searching for answers, describing mothers' search for a diagnosis; 2) (Dis)empowerment, describing mothers' acquisition of knowledge, leading to empowerment; 3) Health care and relationships, describing the impact of relationships on the mother's health care experiences; 4) A juggling act, describing the challenges of juggling health care with school, work and family; 5) Making it work, describing how mothers overcome barriers to access health care for their child.

CONCLUSIONS

The health provider-parent relationship was crucial for fostering positive health care experiences. Mothers' acquisition of knowledge facilitated empowerment within those relationships. Additionally, mothers' perceptions of the quality and benefit of health services motivated them to overcome barriers to accessing care. Study findings may help to improve health care experiences for parents of children with bronchiectasis if identified issues are addressed.

Suspecting non-cystic fibrosis bronchiectasis: What the busy primary care clinician needs to know

AIMS

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic, progressive respiratory disorder characterised by irreversibly and abnormally dilated airways, persistent cough, excessive sputum production and recurrent pulmonary infections. In the last several decades, its prevalence has increased, making it likely to be encountered in the primary care setting. The aim was to review the clinical presentation and diagnosis of NCFB, with an emphasis on the role of computed tomography (CT).

METHODS

For this review, trials and reports were identified from PubMed/Medline and ClinicalTrials.gov from the US NIH and the Cochrane Register of Controlled Trials. The search used keywords: bronchiectasis, non-cystic fibrosis bronchiectasis, chronic pulmonary infection and computed tomography. No date/language restrictions were used.

RESULTS

Non-cystic fibrosis bronchiectasis often coexists with other respiratory conditions, such as chronic obstructive pulmonary disease. The prevalence of NCFB is increasing, particularly in women and older individuals, possibly as a result of increased physician awareness and widespread use of CT, which is the gold standard for the diagnosis of NCFB. CT can assist in identifying an underlying cause of NCFB and determining the extent and severity of the disease.

DISCUSSION

Non-cystic fibrosis bronchiectasis should be suspected in the primary care setting in patients with chronic cough, purulent sputum and frequent respiratory infections that tend to resolve slowly or partially. Early diagnosis and determination of the extent and severity of the disease by CT and other tests are critical to establish therapy to improve quality of life and potentially slow progressive decline of lung function in patients with NCFB.