Is There a Correlation between New Scoring Systems and Systemic Inflammation in Stable Bronchiectasis?

Biomarkers in bronchiectasis

Bronchiectasis is a heterogeneous disease with multiple aetiologies and diverse clinical features. There is a general consensus that optimal treatment requires precision medicine approaches focused on specific treatable disease characteristics, known as treatable traits. Identifying subtypes of conditions with distinct underlying biology (endotypes) depends on the identification of biomarkers that are associated with disease features, prognosis or treatment response and which can be applied in clinical practice. Bronchiectasis is a disease characterised by inflammation, infection, structural lung damage and impaired mucociliary clearance. Increasingly there are available methods to measure each of these components of the disease, revealing heterogeneous inflammatory profiles, microbiota, radiology and mucus and epithelial biology in patients with bronchiectasis. Using emerging biomarkers and omics technologies to guide treatment in bronchiectasis is a promising field of research. Here we review the most recent data on biomarkers in bronchiectasis.

Baseline neutrophil-to-lymphocyte ratio as a predictor of response to hospitalized bronchiectasis exacerbation risks

Background

Bronchiectasis is a disease with predominantly neutrophilic inflammation. As a readily available biomarker, there is little evidence to support the use of blood neutrophil-to-lymphocyte ratio (NLR) to predict bronchiectasis exacerbation severe enough to warrant hospitalization.

Methods

A registry-based retrospective cohort study was conducted at a in Hong Kong. Chinese patients with non-cystic fibrosis (CF) bronchiectasis were retrospectively reviewed and subsequently followed up to investigate the association of NLR and the need for hospitalization for bronchiectasis exacerbation. Data on the NLR for patients in a clinically stable state in 2018 were collected and patients followed up from 1 January 2019 to 31 December 2022. The primary outcome was the need for hospitalization due to bronchiectasis exacerbation over the next 4 years.

Results

We reviewed 473 Chinese patients with non-CF bronchiectasis, of whom 94 required hospitalization for bronchiectasis exacerbation during the 4-year follow-up period. Multi-variable logistic regression adjusted for E-FACED score (Exacerbation, Forced expiratory volume in 1 s (FEV1), Age, Chronic colonization, Extension, and Dyspnea score), gender, age, smoking status, and presence of co-existing chronic obstructive pulmonary disease (COPD) was conducted to compare patients with highest and lowest quartile NLR. Results revealed that those with NLR at the highest quartile were at increased risk of hospitalization for bronchiectasis exacerbation with an adjusted odds ratio (aOR) of 2.02 (95% confidence interval = 1.00-4.12, p = 0.05).

Conclusion

Blood NLR may serve as a marker to predict the need for hospitalization due to bronchiectasis exacerbation.

Bronchiectasis Severity Index and FACED scores in patients with allergic bronchopulmonary aspergillosis complicating asthma: do they correlate with immunological severity or high-attenuation mucus?

Background: The utility of two disease-severity indices, namely bronchiectasis severity index (BSI) and FACED score in allergic bronchopulmonary aspergillosis (ABPA) remains unknown.Objective: To correlate the BSI and FACED scores with immunological parameters (serum IgE [total and A. fumigatus-specific], A. fumigatus-specific IgG, blood eosinophil count), and high-attenuation mucus on chest computed tomography in ABPA. The secondary objectives were to evaluate the correlation between BSI and FACED scores and correlate the BSI/FACED scores with the bronchiectasis health questionnaire (BHQ) and Saint George's Respiratory Questionnaire (SGRQ).Methods: We included treatment-naïve ABPA subjects with bronchiectasis in a prospective observational study. We computed the BSI and FACED scores for each subject before initiating treatment. The subjects also completed two quality-of-life questionnaires (BHQ and SGRQ).Results: We included 91 subjects. The mean (standard deviation) BSI and FACED scores were 3.43 (3.39) and 1.43 (1.27). We found no correlation between BSI or FACED with any immunological parameter or high-attenuation mucus. There was a strong correlation between BSI and FACED scores (r = 0.76, p < 0.001). We found a weak correlation between BSI and BHQ/SGRQ and FACED and SGRQ.Conclusion: We found no correlation between BSI and FACED with immunological parameters in ABPA. However, we found a significant correlation between BSI and FACED and a weak correlation between SGRQ and BHQ. ABPA likely requires a separate disease-severity scoring system.

Peripheral Neutrophil-to-Lymphocyte Ratio in Bronchiectasis: A Marker of Disease Severity

Most patients with bronchiectasis have a predominantly neutrophilic inflammatory profile, although other cells such as lymphocytes (as controllers of bronchial inflammation) and eosinophils also play a significant pathophysiological role. Easy-to-interpret blood biomarkers with a discriminative capacity for severity or prognosis are needed. The objective of this study was to assess whether the peripheral neutrophil-to-lymphocyte ratio (NLR) is associated with different outcomes of severity in bronchiectasis. A total of 1369 patients with bronchiectasis from the Spanish Registry of Bronchiectasis were included. To compare groups, the sample was divided into increasing quartiles of NLR ratio. Correlations between quantitative variables were established using Pearson's P test. A simple linear regression (with the value of exacerbations as a quantitative variable) was used to determine the independent relationship between the number and severity of exacerbations and the NLR ratio. The area under the curve (AUC)-ROC was used to determine the predictive capacity of the NLR for severe bronchiectasis, according to the different multidimensional scores. Mean age: 69 (15) years (66.3% of women). The mean NLR was 2.92 (2.03). A higher NLR was associated with more severe bronchiectasis (with an especially significant discriminative power for severe forms) according to the commonly used scores (FACED, E-FACED and BSI), as well as with poorer quality of life (SGRQ), more comorbidities (Charlson index), infection by pathogenic microorganisms, and greater application of treatment. Furthermore, the NLR correlated better with severity scores than other parameters of systemic inflammation. Finally, it was an independent predictor of the incident number and severity of exacerbations. In conclusion, the NLR is an inexpensive and easy-to-measure marker of systemic inflammation for determining severity and predicting exacerbations (especially the most severe) in patients with bronchiectasis.

Serum Fibrinogen as a Biomarker for Disease Severity and Exacerbation in Patients with Non-Cystic Fibrosis Bronchiectasis

Background: Serum biomarkers associated with severe non-cystic fibrosis (CF) bronchiectasis are currently lacking. We assessed the association of serum fibrinogen, adiponectin, and angiopoietin-2 levels with the severity and exacerbation of bronchiectasis. Methods: Serum levels of fibrinogen, adiponectin, and angiopoietin-2 were measured and compared in patients with stable non-CF bronchiectasis (n = 61) and healthy controls (n = 16). The correlations between the three biomarkers and the bronchiectasis severity index (BSI) or FACED scores were assessed. Univariate and multivariate linear regression analyses were performed to identify variables independently associated with BSI and FACED scores in patients with bronchiectasis. Additionally, the exacerbation-free survival was compared between groups of patients with high and low fibrinogen levels, while the predictors of exacerbation were analyzed using Cox proportional hazards regression. Results: Patients with non-CF bronchiectasis carried higher fibrinogen (3.00 ± 2.31 vs. 1.52 ± 0.74 µg/mL; p = 0.016) and adiponectin (12.3 ± 5.07 vs. 9.17 ± 5.30 µg/mL; p = 0.031) levels compared with healthy controls. The serum level of angiopoietin-2 was comparable between the two groups (1.49 ± 0.96 vs. 1.21 ± 0.79 ng/mL, p = 0.277). Correlations of adiponectin and angiopoietin-2 with BSI and FACED scores were not significant. However, there were significant correlations between fibrinogen and both BSI (r = 0.428) and FACED scores (r = 0.484). Multivariate linear regression analysis revealed that fibrinogen level was an independent variable associated with both BSI and FACED scores. A total of 31 (50.8%) out of 61 patients experienced exacerbation during the follow-up period of 25.4 months. Exacerbation-free survival was significantly longer in patients with low fibrinogen levels than in those with high fibrinogen (log-rank test, p = 0.034). High fibrinogen levels and Pseudomonas colonization were independent risk factors for future exacerbation (HR 2.308; p = 0.03 and HR 2.555; p = 0.02, respectively). Conclusions: Serum fibrinogen, but not adiponectin or angiopoietin-2, is a potential biomarker closely associated with the severity and exacerbation of non-CF bronchiectasis.

Serum albumin is a predictor of respiratory hospitalization in patients with bronchiectasis

We evaluated serum albumin as an index for predicting respiratory hospitalization in patients with bronchiectasis. We retrospectively reviewed the medical records of 177 patients with bronchiectasis, categorized them into low and normal albumin groups, and compared their clinical characteristics. The prediction of respiratory hospitalization by factors such as serum albumin level, bronchiectasis severity index (BSI), and FACED score (an acronym derived from five variables of forced expiratory volume in 1 s; FEV₁, age, chronic colonization of Pseudomonas aeruginosa, extent of bronchiectasis, and dyspnea) was assessed. There were 15 and 162 patients categorized in the low and normal albumin groups, respectively. The low albumin group had lower body mass index and forced expiratory volume in 1 s, and higher age, frequency of previous respiratory hospitalization, percentage of Pseudomonas colonization, number of affected lobes, BSI and FACED scores, and C-reactive protein (CRP) level, than the normal albumin group. The areas under the receiver operating characteristic curve of serum albumin level and BSI and FACED scores for predicting respiratory hospitalization were 0.732 (95% confidence interval (CI), 0.647-0.816), 0.873 (95% CI, 0.817-0.928), and 0.708 (95% CI, 0.618-0.799), respectively. Albumin level, CRP, modified Medical Research Council score, and chronic Pseudomonas aeruginosa (and other organisms) colonization were independent risk factors for respiratory hospitalization. Low serum albumin level was associated with worse clinical condition, higher severity scores, and respiratory hospitalization in patients with bronchiectasis.

A Korean-Style Balanced Diet Has a Potential Connection with Ruminococcaceae Enterotype and Reduction of Metabolic Syndrome Incidence in Korean Adults

Metabolic syndrome is associated with usual dietary patterns that may be involved in enterotypes. We aimed to understand the potential relationship of enterotypes and dietary patterns to influence metabolic syndrome in the Koreans. Using the Korea National Health and Nutrition Examination Survey (KNHANES)-VI in 2014, metabolic parameters were also analyzed among the dietary patterns classified by principal component analysis in Korean adults. The fecal microbiota data of 1199 Korean adults collected in 2014 were obtained from the Korea Centers for Disease Control and Prevention. Enterotypes were classified based on Dirichlet multinomial mixtures (DMM) by Mothur v.1.36. The functional abundance of fecal bacteria was analyzed using the PICRUSt2 pipeline. Korean adults were clustered into three dietary patterns including Korean-style balanced diets (KBD, 20.4%), rice-based diets (RBD, 17.2%), and Western-style diets (WSD, 62.4%) in KNHANES. The incidence of metabolic syndrome was lowered in the order of RBD, WSD, and KBD. The participants having a KBD had lower serum C-reactive protein and triglyceride concentrations than those with RBD and WSD (p < 0.05). Three types of fecal bacteria were classified as Ruminococcaceae type (ET-R, 28.7%), Prevotella type (ET-P, 52.2%), and Bacteroides type (ET-B, 42.1%; p < 0.05). ET-P had a higher abundance of Prevotella copri, while ET-R contained a higher abundance of Alistipes, Akkermansia muciniphila, Bifidobacterium adolescentis, and Faecalibacterium prausnitzii. ET-B had a higher abundance of the order Bilophila (p < 0.05). Metabolism of propanoate, starch, and sucrose in fecal microbiome was higher in ET-P and ET-R, whereas fatty acid metabolism was enhanced in ET-B. Fecal microbiota in ET-P and ET-B had higher lipopolysaccharide biosynthesis activity than that in ET-R. The metabolic results of KBD and RBD were consistent with ET-R and ET-P’s gut microbiota metabolism, respectively. In conclusion, Korean enterotypes of ET-P, ET-B, and ET-R were associated with RBD, WSD, and KBD, respectively. This study suggests a potential link between dietary patterns, metabolic syndrome, and enterotypes among Korean adults.

Systemic Inflammation and Oxidative Stress in Adults with Bronchiectasis: Association with Clinical and Functional Features

OBJECTIVES

To compare the inflammatory and oxidative stress (OS) states of adults with bronchiectasis with those of healthy controls and correlate inflammatory and OS levels with lung function and physical capacity.

METHODS

This study used a cross-sectional design. Seventy-four adults with bronchiectasis (age: 49±15 years, forced expiratory volume in 1 second [FEV1]: 52.5±25.6%) and 42 healthy controls (age: 44±17 years, FEV1: 95.9±14.0%) performed cardiopulmonary exercise tests and incremental shuttle walking tests. Their physical activity in daily life, inflammatory cytokine, and antioxidant levels in plasma were measured.

RESULTS

Compared to that of the controls, the levels of interleukin (IL)-6 (p<0.001), IL-10 (p<0.001), carbonylated proteins (p=0.001), and superoxide anions (p=0.046) were significantly increased in adults with bronchiectasis. Catalase activity was also reduced in this group (p<0.001). The inflammatory markers IL-1β, IL-6, and tumor necrosis factor-α correlated negatively with aerobic capacity (r=-0.408, r=-0.308, and r=-0.207, respectively). We observed similar correlations with OS markers (thiobarbituric acid and carbonyls; r=-0.290 and r=0.379, respectively), and these markers also significantly correlated with the aerobic capacity.

CONCLUSIONS

Adults with bronchiectasis presented an increased systemic inflammatory response that correlated negatively with physical capacity.

Utility of Bronchiectasis severity index (BSI) as prognostic tool in patients with post tubercular bronchiectasis: An experience from a tertiary care hospital in North India

BACKGROUND

Bronchiectasis severity Index (BSI) score which predicts the severity of the disease along with future exacerbations and mortality rate has been well validated in European patients; however there is paucity of data evaluating its validity in Indian patients. The authors therefore decided to evaluate the utility of BSI to predict exacerbations and mortality rate in patients with post tubercular bronchiectasis presenting to our facility.

METHODS

The study was a retrospective observational study done in patients with bronchiectasis secondary to tuberculosis. These patients were followed up for 4 years. BSI was calculated from different variables and descriptive statistics along with regression analysis were used to evaluate utility of BSI.

RESULTS

A total of 48 patients of post tubercular bronchiectasis were included in the study. Majority of our patients belonged to severe bronchiectasis group seen in 23 patients (48%) while those with mild and moderate bronchiectasis were seen in 13 (27%) and 12 (25%) patients respectively. The exacerbation rate in mild group was comparable to the predicted BSI exacerbation at 1 year while the predicted and observed rates were statistically significant for moderate and severe bronchiectasis group (p value < 0.05). Mortality rates at 1 year were comparable in all the groups of bronchiectasis while it was comparable only in mild and moderate group bronchiectasis at 4 years.

CONCLUSION

Bronchiectasis severity index seems to predict mortality at 1 year in post tuberculosis bronchiectasis. However, it under predicts 1 year and 4 year exacerbation rates. Hence BSI may not be useful as a prognostic tool in Indian patients with bronchiectasis. Larger multi-centred studies may be required to further evaluate the clinical utility of BSI among Indian population.

Neutrophils to Lymphocyte Ratio as a Biomarker in Bronchiectasis Exacerbation: A Retrospective Study

Introduction

Bronchiectasis is a disorder resulting mainly from bronchial inflammation caused by recurrent or chronic infections. It is characterized by permanently dilated airways due to bronchial wall destruction. Exacerbations have a key role in bronchiectasis as they are associated with a negative impact on patient prognosis. Exacerbations are generally infectious events caused mostly by bacterial microorganisms. Infective or inflammatory agents cause neutrophil recruitment into the airways, which leads to proteolytic enzymes such as neutrophil elastase and matrix metalloproteinases release, resulting in airway matrix destruction. Neutrophil to lymphocyte ratio (NLR) is used as a biomarker of inflammation. It is calculated by dividing the number of neutrophils by the number of lymphocytes. Our aim is to evaluate Neutrophils to Lymphocyte Ratio in patients with bronchiectasis exacerbation and its correlation to microbiological data.

Methods 

The study involved patients with a diagnosis of bronchiectasis based on high-resolution computerised tomography (HRCT) of the chest who fulfilled the criteria of bronchiectasis exacerbation. Complete blood counts with differential counts, which included total white blood cells, neutrophils and lymphocytes, were obtained. NLR and C-reactive protein (CRP) levels were measured in patients with bronchiectasis exacerbation and in healthy controls. NLR was calculated as the ratio of the neutrophils to lymphocytes. The mean NLR values in patients with bronchiectasis exacerbation were compared to mean NLR values in healthy controls. The NLR values were compared to CRP levels in patients with bronchiectasis exacerbation. Sputum cultures were performed in all patients. The mean NLR values in patients with positive sputum cultures were compared with mean NLR values in patients with negative sputum cultures, and mean NLR values in patients with isolated Pseudomonas aeruginosa in sputum cultures were compared to mean NLR values in patients with other infectious agents isolated.

Results

The study population consisted of 80 patients with bronchiectasis exacerbation - 54 males and 26 females - with a mean age of 77.3±8.4 years, and 64 healthy controls - 36 males and 28 females - with a mean age of 62.9±15.3 years. The mean CRP levels in patients with bronchiectasis exacerbation were 75.03±73.87 mg/l. The mean NLR value in patients with bronchiectasis exacerbation was 9.2±7.8 and the mean NLR value of controls was 3.1±2.9 (p<0.001). The NLR values in patients with bronchiectasis exacerbation had no linear correlation with CRP values in these patients (r=0.002, p=0.992). Fifty-two patients had positive sputum cultures and 28 patients had negative sputum cultures. The mean NLR value in patients with positive sputum cultures was 10.5±9.1, and in patients with negative sputum cultures, it was 6.7±3.6 (p<0.012). The mean NLR value in patients with P.aeruginosa was 10.1±9.5, and in patients with other microorganisms isolated, it was 10.8±8.9 (p=0.784).

Conclusions

Neutrophil to lymphocyte ratio values are statistically greater in patients with bronchiectasis exacerbation compared to healthy controls. There is no linear correlation between NLR and CRP in these patients. NLR values are statistically greater in patients with positive sputum cultures compared to those with negative sputum cultures. Therefore, NLR can be used for predicting positive cultures in patients with bronchiectasis exacerbation.

Effect of Bronchodilator and Steroid Use on Heart Disease and Stroke Risks in a Bronchiectasis-Chronic Obstructive Pulmonary Disease Overlap Cohort: A Propensity Score Matching Study

Background: To determine the effects of bronchodilator, steroid, and anti-arrhythmia drug use on the risk of heart disease/stroke (HDS) in patients with bronchiectasis–chronic obstructive pulmonary disease overlap syndrome (BCOS).

Methods: We retrospectively enrolled patients with BCOS (BCOS cohort, n = 1,493) and patients without bronchiectasis and chronic obstructive pulmonary disease (COPD) (non-BCOS cohort, n = 5,972). The cumulative incidence of HDS was analyzed through Cox proportional regression. We calculated adjusted hazard ratios (aHRs) and their 95% confidence intervals (CIs) for HDS after adjustments for sex, age, comorbidities, long-acting β2-agonist or long-acting muscarinic antagonist (LABAs/LAMAs) use, short-acting β2-agonist or short-acting muscarinic antagonist (SABAs/SAMAs) use, oral steroid (OSs) or inhaled corticosteroid steroid (ICSs) use, and anti-arrhythmia drugs use.

Results: The aHR (95% CI) for HDS was 1.08 (0.28–4.06) for patients using LAMAs compared with those not using drugs. Regarding drug use days, the aHRs (95% CIs) were 32.2 (1.79–773.0), 1.85 (1.01–3.39), and 31.1 (3.25–297.80) for those with recent SABAs use, past ICSs use, and past anti-arrythmia drugs use, respectively. Regarding cumulative drug dose, the aHRs (95% CIs) were 2.12 (1.46–3.10), 3.48 (1.13–10.6), 3.19 (2.04–4.99), 28.1 (1.42–555.7), 2.09 (1.32–3.29), 2.28 (1.53–3.40), and 1.93 (1.36–2.74) for those with a low dose of SABAs, medium dose of SABAs, low dose of SAMAs, low dose of ICSs, medium dose of ICSs, low dose of OSs, and medium dose of OSs, respectively.

Conclusions: Compared with patients without bronchiectasis and COPD, BCOS patients with recent SABAs, past ICSs, and past anti-arrhythmia drugs use; a low or medium SABAs ICSs, and OSs dose; and a low SAMAs dose had a higher risk of HDS. LAMAs were not associated with HDS.

Serum Biomarkers in Patients with Stable and Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Comparative Study

BACKGROUND

Mean platelet volume (MPV), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have all been investigated as novel inflammatory markers of cardiac and oncological diseases, while there is only a limited number of studies investigating these markers in chronic obstructive pulmonary disease (COPD). In the present study we examine NLR, PLR; and other markers, such as eosinophil, MPV, plateletcrit (PCT), platelet distribution width (PDW), red cell distribution width (RDW), and C-reactive protein (CRP) in patients with stable and acute exacerbation of COPD.

METHODS

Stable COPD (Group 1, n=140), COPD with acute exacerbation (Group 2, n=110), and healthy controls (Group 3, n=50) were included in the study. Leukocyte, CRP, hemoglobin (HB), RDW, platelet, MPV, PCT, PDW, neutrophil, lymphocyte, eosinophil, NLR, and PLR were analyzed in all groups.

RESULTS

HB, leukocyte, platelet, neutrophil, eosinophil, MPV, PCT, CRP, NLR, and PLR were significantly higher, while the lymphocyte was lower in Group 1 than in Group 3. Leukocyte, neutrophil, RDW, CRP, NLR, and PLR were significantly higher, while lymphocyte was lower in Group 2 than in Group 3. Leukocyte, neutrophil, RDW, CRP, NLR, and PLR were significantly higher, while HB, platelet, MPV, PCT, and lymphocyte were significantly lower in Group 2 than in Group 1. NLR and PLR increased significantly in patients with bronchiectasis when compared to those without in Group 1.

CONCLUSIONS

Our study results suggest that NLR, PLR and RDW can be used as simple and cost-effective markers for the evaluation of severity of exacerbation and for predicting hospitalization and further exacerbations in patients with COPD.

Brazilian consensus on non-cystic fibrosis bronchiectasis

Bronchiectasis is a condition that has been increasingly diagnosed by chest HRCT. In the literature, bronchiectasis is divided into bronchiectasis secondary to cystic fibrosis and bronchiectasis not associated with cystic fibrosis, which is termed non-cystic fibrosis bronchiectasis. Many causes can lead to the development of bronchiectasis, and patients usually have chronic airway symptoms, recurrent infections, and CT abnormalities consistent with the condition. The first international guideline on the diagnosis and treatment of non-cystic fibrosis bronchiectasis was published in 2010. In Brazil, this is the first review document aimed at systematizing the knowledge that has been accumulated on the subject to date. Because there is insufficient evidence on which to base recommendations for various treatment topics, here the decision was made to prepare an expert consensus document. The Brazilian Thoracic Association Committee on Respiratory Infections summoned 10 pulmonologists with expertise in bronchiectasis in Brazil to conduct a critical assessment of the available scientific evidence and international guidelines, as well as to identify aspects that are relevant to the understanding of the heterogeneity of bronchiectasis and to its diagnostic and therapeutic management. Five broad topics were established (pathophysiology, diagnosis, monitoring of stable patients, treatment of stable patients, and management of exacerbations). After this subdivision, the topics were distributed among the authors, who conducted a nonsystematic review of the literature, giving priority to major publications in the specific areas, including original articles, review articles, and systematic reviews. The authors reviewed and commented on all topics, producing a single final document that was approved by consensus.

Assessing effects of inhaled antibiotics in adults with non-cystic fibrosis bronchiectasis--experiences from recent clinical trials

INTRODUCTION

Non-cystic fibrosis bronchiectasis (NCFB) results from a permanent and progressive destruction of the airways leading to poor lung function. NCFB is characterized by recurrent lung infection, sputum production, and cough, often requiring long-term antibiotic therapy and hospitalization. At present, there are no approved therapies available. Clinical trials of inhaled antibiotics have shown promise against sputum bacterial load, but mixed results on clinical outcomes. Areas covered: The objective of this review is to provide an overview of NCFB and critically evaluate the evidence supporting the outcome measures used in recent clinical trials of inhaled antibiotics. These include quantitative changes in bacterial load, sputum purulence and yield, inflammatory markers, and lung function, as well as clinical changes in exacerbations, exacerbation frequency, hospitalizations, and health-related quality of life. Expert commentary: Recently completed large trials of inhaled antibiotics in NCFB did not consistently meet pre-specified end points, suggesting that we have not yet found the best enrollment criteria or outcome measures to evaluate efficacy, although reduced exacerbation frequency may be clinically most meaningful. Future trials may focus on specific patient populations at high risk with new information obtained through analyses of large international patient registries.

ABBREVIATIONS

6-MWT: Six-Minute Walk Test; AIR-BX: Aztreonam for Inhalation Solution in Patients with Non-Cystic Fibrosis Bronchiectasis trial; BSI: Bronchiectasis Severity Index; CAT: COPD Assessment Test; CF: Cystic Fibrosis; CFTR: Cystic Fibrosis Transmembrane Conductance Regulator; CFU: Colony-Forming Units; COPD: Chronic Obstructive Pulmonary Disease; CRP: C-Reactive Protein; DPI: Dry Powder for Inhalation; EMA: European Medicines Agency; ERS: European Respiratory Society; FACED: FEV1, Age, Chronic colonization by P. aeruginosa, Extension of bronchiectasis and Dyspnea; FDA: US Food and Drug Administration; FEV₁: Forced Expiration in 1 s; FVC: Forced Vital Capacity; HFCC: High-Frequency Chest Compression; HRCT: High-Resolution Computed Tomography; HRQoL: Health-Related Quality of Life; LCQ: Leicester Cough Questionnaire; MID: Minimal Important Difference; NCFB: Non-Cystic Fibrosis Bronchiectasis; NTM: Nontuberculous Mycobacteria; ORBIT: Once-daily Respiratory Bronchiectasis Inhalation Treatment trial; PRO: Patient-Reported Outcomes; QoL-B: Quality of Life-Bronchiectasis; SGRQ: St. George's Respiratory Questionnaire; SWT: Shuttle Walk Test; TORCH: Towards a Revolution in COPD Health trial; UPLIFT: Understanding Potential Long-term Impacts on Function with Tiotropium trial.