Distinct Phenotypes of Smokers with Fixed Airflow Limitation Identified by Cluster Analysis of Severe Asthma

Increased adiposity-to-muscle ratio and severity of sinusitis affect quality of life in asthma: Computed tomographic analysis

Background

Deteriorated sinusitis and increased adiposity relative to muscle mass may affect quality of life in patients with asthma. However, whether these effects are observed regardless of intrapulmonary pathology is unknown.

Objectives

We evaluated the correlation of the cross-sectional ratio of abdominal visceral fat (VF) to erector spinae muscle (ESM) and sinus findings based on Lund-Mackey scoring system (LMS) on computed tomography (CT) with the impaired score of the Asthma Quality of Life Questionnaire (AQLQ), regardless of airway and parenchymal disease, in patients with asthma.

Methods

We recruited participants from the Hokkaido-based severe asthma cohort who had completed AQLQ and CT examination at the entry. The participants were divided into high (highest) and low (other quartiles) groups on the bases of the extrapulmonary indices. Multivariate analysis examined the association of VF/ESM for the adiposity-to-muscle ratio and LMS with AQLQ after adjusting for the airway fractal dimension for airway index and percentage of low attenuation volume to lung volume for parenchymal index.

Results

No significant differences were observed in VF/ESM and LMS in terms of sex. The AQLQ score in the high VF/ESM group and high LMS group was lower than those in low VF/ESM group and low LMS group (63 male and 100 female subjects). High VF/ESM (estimate [95% confidence interval] (-0.43 [-0.61, -0.25]) and high LMS scores (-0.22 [-0.41, -0.03]) were associated with low AQLQ scores when adjusted for age, body mass index, smoking status, blood eosinophil count, and intrapulmonary CT indices.

Conclusions

Increased VF relative to ESM mass and high LMS may deteriorate asthma-related quality of life, regardless of presence of intrapulmonary disease.

Risk factor analysis and nomogram for predicting poor symptom control in smoking asthmatics

BACKGROUND

Smoking induces and modifies the airway immune response, accelerating the decline of asthmatics' lung function and severely affecting asthma symptoms' control level. To assess the prognosis of asthmatics who smoke and to provide reasonable recommendations for treatment, we constructed a nomogram prediction model.

METHODS

General and clinical data were collected from April to September 2021 from smoking asthmatics aged ≥14 years attending the People's Hospital of Zhengzhou University. Patients were followed up regularly by telephone or outpatient visits, and their medication and follow-up visits were recorded during the 6-months follow-up visit, as well as their asthma control levels after 6 months (asthma control questionnaire-5, ACQ-5). The study employed R4.2.2 software to conduct univariate and multivariate logistic regression analyses to identify independent risk factors for 'poorly controlled asthma' (ACQ>0.75) as the outcome variable. Subsequently, a nomogram prediction model was constructed. Internal validation was used to test the reproducibility of the model. The model efficacy was evaluated using the consistency index (C-index), receiver operating characteristic (ROC) curve, calibration curve, and decision curve.

RESULTS

Invitations were sent to 231 asthmatics who smoked. A total of 202 participants responded, resulting in a final total of 190 participants included in the model development. The nomogram established five independent risk factors (P<0.05): FEV1%pred, smoking index (100), comorbidities situations, medication regimen, and good or poor medication adherence. The area under curve (AUC) of the modeling set was 0.824(95%CI 0.765-0.884), suggesting that the nomogram has a high ability to distinguish poor asthma control in smoking asthmatics after 6 months. The calibration curve showed a C-index of 0.824 for the modeling set and a C-index of 0.792 for the self-validation set formed by 1000 bootstrap sampling, which means that the prediction probability of the model was consistent with reality. Decision curve analysis (DCA) of the nomogram revealed that the net benefit was higher when the risk threshold probability for poor asthma control was 4.5 - 93.9%.

CONCLUSIONS

FEV1%pred, smoking index (100), comorbidities situations, medication regimen, and medication adherence were identified as independent risk factors for poor asthma control after 6 months in smoking asthmatics. The nomogram established based on these findings can effectively predict relevant risk and provide clinicians with a reference to identify the poorly controlled population with smoking asthma as early as possible, and to select a better therapeutic regimen. Meanwhile, it can effectively improve the medication adherence and the degree of attention to complications in smoking asthma patients.

Applicable predictive factors extracted from peak flow trajectory for the prediction of asthma exacerbation

BACKGROUND

Real-time asthma exacerbation prediction and acute asthma attack detection are essential for patients with severe asthma. Peak expiratory flow (PEF) exhibits a potential for use in long-term asthma self-monitoring. However, the method for processing PEF calculations remains to be clarified.

OBJECTIVE

To develop clinically applicable novel exacerbation predictors calculated using PEF records.

METHODS

Previously proposed exacerbation predictors, including the slope of PEF, percentage predicted PEF, percentage best PEF, the highest PEF over the lowest PEF within specific periods, and PEF coefficient of variation, in addition to a novel indicator delta PEF moving average (ΔMA), defined as the difference between 14-day and 3-day average PEF values, along with moving average (MA) adjusted for PEF reference (%ΔMA), were verified using the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma data of 127 patients with severe asthma from whom 73,503 PEF observations were obtained. Receiver operating characteristic curves for all predictors were drawn, and the corresponding areas under the curve (AUCs) were computed. Regression analysis for MA and percentage MA were conducted.

RESULTS

The most outstanding performance was shown by ΔMA and %ΔMA, with AUC values of 0.659 and 0.665 in the univariate model, respectively. When multivariate models were incorporated with random intercepts for individual participants, the AUC for ΔMA and %ΔMA increased to 0.907 and 0.919, respectively.

CONCLUSION

The MA and percentage MA are valuable indicators that should be considered when deriving predictors from the PEF trajectory for monitoring exacerbations in patients with severe asthma.

TRIAL REGISTRATION

The Hokkaido-based Investigative Cohort Analysis for Refractory Asthma was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN ID: 000003254). https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000003917.

Impact of obesity in asthma: Possible future therapies

Obesity is one of the factors associated with the severity of asthma. Obesity is associated with aggravation of the pathophysiology of asthma, including exacerbations, airway inflammation, decreased pulmonary function, and airway hyperresponsiveness. The present review addresses the characteristics of asthma with obesity, focusing especially on the heterogeneity caused by the degree of type 2 inflammation, sex differences, the onset of asthma, and race differences. To understand the severity mechanisms in asthma and obesity, such as corticosteroid resistance, fatty acids, gut microbiome, and cytokines, several basic research studies are evaluated. Finally, possible future therapies, including weight reduction, microbiome-targeted therapies, and other molecular targeted therapies are addressed. We believe that the present review will contribute to better understanding of the severity mechanisms and the establishment of novel treatments for severe asthma patients with obesity.

Serum MMP3 and IL1-RA levels may be useful biomarkers for detecting asthma and chronic obstructive pulmonary disease overlap in patients with asthma

Background

Asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO) is characterized by concurrent features of asthma and COPD. Since disease pathogenesis, severities, and treatments differ between asthma and ACO, it is important to differentiate them.

Objective

To clarify and compare the characteristics of ACO and asthma and identify the serum biomarkers for differentiating them, especially in older patients.

Methods

This study used the data of 639 participants from the nationwide cohort study, the NHOM-Asthma study, an asthma registry in Japan, with complete information on smoking history, respiratory function, and serum biomarkers. ACO was defined as the self-reported comorbidity of COPD or emphysema, or with obstructive pulmonary function and smoking history (pack-years≥10). The clinical characteristics of patients with ACO and asthma without COPD were compared. The serum biomarkers for differentiation were examined using receiver operating characteristic curves and multivariable analysis. The associations between the biomarkers and age were also analyzed.

Results

Of the 639 asthma patients, 125 (19.6%) were diagnosed with ACO; these patients were older and male-dominant and had a higher prevalence of comorbidities such as hypertension, diabetes, and stroke. Among the serum biomarkers that were significantly different between ACO and asthma without COPD, the YKL-40/CHI3L1, MMP3, and IL-1RA levels showed a high area under the curve for discriminating ACO. Only the MMP3 and IL-1RA levels were significantly higher among ACO patients, regardless of age and sex; the YKL-40/CHI3L1 levels were not different due to the effect of age.

Conclusion

MMP3 and IL-1RA may be useful serum biomarkers for distinguishing ACO from asthma.

Prospective Real-World Analysis of Asthma Patients With Preserved and Reduced Physical Activity

BACKGROUND

Asthma is a highly heterogeneous airway disease, and the clinical characteristics of patients with asthma with preserved and reduced physical activity are poorly understood.

OBJECTIVE

We aimed to investigate the risk factors and clinical phenotypes associated with reduced physical activity in a wide range of patients with asthma.

METHODS

We conducted a prospective observational study of 138 patients with asthma, including patients with asthma without chronic obstructive pulmonary disease (COPD) (n = 104) and asthma-COPD overlap (n = 34), and 42 healthy controls. Physical activity levels were measured for 2 weeks using a triaxial accelerometer at baseline and 1 year later.

RESULTS

Higher eosinophils and body mass index (BMI) were associated with reduced physical activity in patients with asthma without COPD. Cluster analysis of asthma without COPD revealed 4 asthma phenotypes. We identified a cluster with preserved physical activity (n = 43) that was characterized by good symptom control and lung function and included a high proportion of biologics users (34.9%). Multivariate regression analysis revealed that patients with late-onset eosinophilic (n = 21), high-BMI noneosinophilic (n = 14), and symptom-predominant asthma phenotypes (n = 26) had lower levels of physical activity than controls. Patients with asthma-COPD overlap also had significantly lower physical activity levels than controls. Similar trends in physical activity levels were observed in each asthma group at 1-year follow-up.

CONCLUSION

This study showed the clinical features of patients with asthma with preserved and reduced physical activity. Reduced physical activity was observed in various asthma phenotypes and in asthma-COPD overlap.

Clinical characteristics and natural course of chronic obstructive pulmonary disease and/or asthma in Japanese patients: a summary report of two Hokkaido-based cohort studies

Chronic obstructive pulmonary disease (COPD) and asthma are the most common chronic airway diseases and are characterized by chronic airway inflammation and airflow limitation. Japanese patients with COPD or asthma have characteristics different from those of Westerners. Therefore, understanding the characteristics and clinical course of Japanese patients with COPD and those with asthma, particularly severe asthma, is critical for their management and appropriate treatment. The Hokkaido COPD cohort and Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) are high-quality cohort studies of COPD and asthma in the Japanese population and provide valuable data. This report summarizes the clinical findings from the two cohort studies and provides data for more appropriate management of Japanese patients with COPD and/or asthma. Overall, 279 patients with COPD were followed up for up to 10 years in the Hokkaido COPD cohort study, and 127 with severe asthma were followed up for up to 6 years in the Hi-CARAT study. Seventy-nine patients with mild-to-moderate asthma provided baseline data for the Hi-CARAT study. In each disease, several distinct factors, including systemic status and non-pulmonary factors, were associated with important clinical outcomes, such as lung function decline, exacerbations, impaired quality of life, and mortality. Therefore, multifaceted evaluation based on the characteristics of the Japanese population is necessary for the management of COPD and asthma.

Asthma and Fixed Airways Obstruction: Real Life Aspects

We aimed to evaluate asthmatic patients with fixed airways obstruction (FAO) and to verify the impact of follow-up in an asthma-dedicated outpatient clinic on symptoms control and spirometry compared to asthmatics without FAO. We enrolled 20 asthmatic FAO+ patients and 20 FAO- asthmatics at baseline (T0) and at a one-year follow-up visit (T1). FAO+ and FAO- groups were compared for anamnesis, FEV1, asthma control test (ACT) and their ΔT0-T1. FAO+ and FAO- groups did not differ for age, BMI, pack-years, allergy, T0 blood eosinophils, comorbidities or GINA therapy step at T0 and T1, whereas, in the FAO+ group, we found more patients with a delay >5 years between symptoms onset and correct asthma diagnosis (p < 0.05). ACT at T0 and ΔT0-T1, FEV1 at ΔT0-T1 and number of exacerbations at T0 and ΔT0-T1 did not differ between groups. Despite a widespread perception of FAO, per se, as a severity factor for asthma, we found similar severity profiles and amelioration after one year of treatment in the FAO+ and FAO- groups. The only factor linked to FAO development in our population was a delay in asthma diagnosis from respiratory symptoms onset, which may have led to airway remodeling. Physicians should characterize patients with FAO for avoiding misdiagnosis between asthma and other respiratory diseases and for establishing the appropriate therapy.

Relationships of computed tomography-based small vessel indices of the lungs with ventilation heterogeneity and high transfer coefficients in non-smokers with asthma

Background: The mechanism of high transfer coefficients of the lungs for carbon monoxide (Kco) in non-smokers with asthma is explained by the redistribution of blood flow to the area with preserved ventilation, to match the ventilation perfusion. Objectives: To examine whether ventilation heterogeneity, assessed by pulmonary function tests, is associated with computed tomography (CT)-based vascular indices and Kco in patients with asthma. Methods: Participants were enrolled from the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) study that included a prospective asthmatic cohort. Pulmonary function tests including Kco, using single breath methods; total lung capacity (TLC), using multiple breath methods; and CT, were performed on the same day. The ratio of the lung volume assessed using single breath methods (alveolar volume; V_A) to that using multiple breath methods (TLC) was calculated as an index of ventilation heterogeneity. The volume of the pulmonary small vessels <5 mm² in the whole lung (BV5 volume), and number of BV5 at a theoretical surface area of the lungs from the plural surface (BV5 number) were evaluated using chest CT images. Results: The low V_A/TLC group (the lowest quartile) had significantly lower BV5 number, BV5 volume, higher BV5 volume/BV5 number, and higher Kco compared to the high V_A/TLC group (the highest quartile) in 117 non-smokers, but not in 67 smokers. Multivariable analysis showed that low V_A/TLC was associated with low BV5 number, after adjusting for age, sex, weight, lung volume on CT, and CT emphysema index in non-smokers (not in smokers). Conclusion: Ventilation heterogeneity may be associated with low BV5 number and high Kco in non-smokers (not in smokers). Future studies need to determine the dynamic regional system in ventilation, perfusion, and diffusion in asthma.

Association of serum CC16 levels with eosinophilic inflammation and respiratory dysfunction in severe asthma

BACKGROUND

There are knowledge gaps in the potential role of Club cell 16-kDa secretory protein (CC16) in severe asthma phenotypes and type 2 inflammation, as well as the longitudinal effect of CC16 on pulmonary function tests and exacerbation risk in epidemiological studies.

OBJECTIVE AND METHODS

To assess whether serum CC16 is associated with eosinophilic inflammation in patients with severe asthma. We also examined the effect of this protein on the annual decline in forced expiratory volume in the first second (FEV₁) and the risk of exacerbation using a longitudinal approach. We recruited 127 patients with severe asthma from 30 hospitals/pulmonary clinics in Hokkaido, Japan. The least square means and standard error were calculated for T-helper 2 (Th2) biomarkers and pulmonary function test across CC16 tertiles at baseline. We did the same for asthma exacerbation and annual decline in FEV₁ with 3 and 5 years' follow-up, respectively.

RESULTS

We found that serum CC16 was inversely associated with sputum eosinophils and blood periostin in a dose-response manner. Baseline CC16 and FEV₁/forced vital capacity ratio were positively associated in adjusted models (p for trend = 0.008). Patients with the lowest tertile of serum CC16 levels at baseline had a -14.3 mL decline in FEV₁ than those with the highest tertile over 5 years of follow-up (p for trend = 0.031, fully adjusted model). We did not find any association of CC16 with exacerbation risk.

CONCLUSION

Patients with severe asthma with lower circulatory CC16 had enhanced eosinophilic inflammation with rapid FEV₁ decline over time.

Classifications of moderate to severe asthma phenotypes in Japan and analysis of serum biomarkers: A Nationwide Cohort Study in Japan (NHOM Asthma Study)

BACKGROUND

Asthma is a heterogeneous disease, and phenotyping can facilitate understanding of disease pathogenesis and direct appropriate asthma treatment. This nationwide cohort study aimed to phenotype asthma patients in Japan and identify potential biomarkers to classify the phenotypes.

METHODS

Adult asthma patients (n = 1925) from 27 national hospitals in Japan were enrolled and divided into Global Initiative for Asthma (GINA) steps 4 or 5 (GINA 4, 5) and GINA Steps 1, 2, or 3 (GINA 1-3) for therapy. Clinical data and questionnaires were collected. Biomarker levels among GINA 4, 5 patients were measured. Ward's minimum variance hierarchical clustering method and tree analysis were performed for phenotyping. Analysis of variance, the Kruskal-Wallis, and chi-square tests were used to compare cluster differences.

RESULTS

The following five clusters were identified: 1) late-onset, old, less-atopic; 2) late-onset, old, eosinophilic, low FEV₁; 3) early-onset, long-duration, atopic, poorly controlled; 4) early-onset, young, female-dominant, atopic; and 5) female-dominant, T1/T2-mixed, most severe. Age of onset, disease duration, blood eosinophils and neutrophils, asthma control questionnaire Sum 6, number of controllers, FEV₁, body mass index (BMI), and hypertension were the phenotype-classifying variables determined by tree analysis that assigned 79.5% to the appropriate cluster. Among the cytokines measured, IL-1RA, YKL40/CHI3L1, IP-10/CXCL10, RANTES/CCL5, and TIMP-1 were useful biomarkers for classifying GINA 4, 5 phenotypes.

CONCLUSIONS

Five distinct phenotypes were identified for moderate to severe asthma and may be classified using clinical and molecular variables (Registered in UMIN-CTR; UMIN000027776.).

Blood eosinophil count variability in chronic obstructive pulmonary disease and severe asthma

BACKGROUND

Blood eosinophils are essential biomarkers that vary substantially over time in patients with COPD and asthma. However, no study has identified the changes and effects in the changes of the blood eosinophil counts over time in both diseases. This study aimed to demonstrate blood eosinophil variability in patients with COPD and severe asthma based on these backgrounds.

METHODS

A total of 172 patients with COPD from the Hokkaido COPD cohort study and 96 patients with severe asthma from the Hokkaido Severe Asthma Cohort Study, whose blood eosinophil counts were measured annually over a 3-year period, were analyzed. The factors contributing to consistently high or low blood eosinophil counts were examined in each cohort. The stability of the eosinophil classification (<150, 150-299, ≥300 cells/μL) was compared based on the number of asthma-like features in patients with COPD and the smoking status in patients with severe asthma.

RESULTS

Among all the patients, the most stable range of baseline blood eosinophil counts differed between the two diseases, with <150 cells/μL in COPD and ≥300 cells/μL in severe asthma. In COPD, the number of asthma-like features (bronchodilator reversibility, blood eosinophilia, and atopy) affects the blood eosinophil count variation patterns. In severe asthma, smoking status did not affect the blood eosinophil count variation patterns.

CONCLUSIONS

We identified variations in the blood eosinophil counts and their contributing factors in patients with COPD and severe asthma.

Relevance of Smoking Habit in Severe Asthma Patients: Evidence from the Severe Asthma Network in Italy (SANI) Registry

Smoking habit is still fairly common among asthmatics. So far, the impact of smoke on severe asthma burden has not been specifically investigated. We aimed to estimate the frequency of smoking habit among severe asthma patients, their clinical features, and the impact of smoke on asthma outcomes. The Severe Asthma Network in Italy (SANI) registry was analyzed. Demographic, clinical, and functional features of smokers, never and former smokers were compared. Data from 1194 patients were explored. Smokers were younger, with a lower asthma onset age. Atopy, BMI and respiratory/systemic comorbidities were equally distributed. In former smokers pre- and post-FEV1/FVC was significantly lower; no other significant differences were detected. Similar findings were confirmed when stratifying the former smokers by pack-years and length of smoking cessation. Among former smokers, lymphocytes and neutrophils were higher in the <15 years of smoking cessation group. Blood eosinophils were comparable in never and former smokers. When clustering the population by blood eosinophils, no significant differences in pulmonary function and exacerbations were observed. Our data suggest that a personal smoking history has a relatively low impact on disease burden. It remarks the importance of smoking cessation as a main intervention, particularly in severe asthma.

Differential role of mucus plugs in asthma: Effects of smoking and association with airway inflammation

BACKGROUND

The physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical-physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma.

METHODS

A total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT.

RESULTS

More mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics.

CONCLUSIONS

The association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma.

Diversities of allergic pathologies and their modifiers: Report from the second DGAKI-JSA meeting

In October 2021, researchers from the German Society of Allergy and Clinical Immunology (DGAKI) and from the Japanese Society of Allergology (JSA) focused their attention on the pathological conditions and modifiers of various allergic diseases. Topics included 1) the pathophysiology of IgE/mast cell-mediated allergic diseases; 2) the diagnosis and prevention of IgE/mast cell-mediated diseases; 3) the pathophysiology, diagnosis, and treatment of eosinophilic airway diseases; and 4) host-pathogen interaction and allergic diseases. This report summarizes the panel discussions, which highlighted the importance of recognizing the diversity of genetics, immunological mechanisms, and modifying factors underlying allergic diseases.

Effects of obesity on CC16 and their potential role in overweight/obese asthma

Introduction

Club cell secretory protein-16 (CC16) is a major anti-inflammatory protein expressed in the airway; however, the potential role of CC16 on overweight/obese asthma has not been assessed. In this study, we examined whether obesity reduces airway/circulatory CC16 levels using experimental and epidemiological studies. Then, we explored the mediatory role of CC16 in the relationship of overweight/obesity with clinical asthma measures.

Methods

Circulating CC16 levels were assessed by ELISA in three independent human populations, including two groups of healthy and general populations and asthma patients. The percentage of cells expressing club markers in obese vs. non-obese mice and human airways was determined by immunohistochemistry. A causal mediation analysis was conducted to determine whether circulatory CC16 acted as a mediator between overweight/obesity and clinical asthma measures.

Results

BMI was significantly and monotonously associated with reduced circulating CC16 levels in all populations. The percentage of CC16-expressing cells was reduced in the small airways of both mice and humans with obesity. Finally, mediation analysis revealed significant contributions of circulatory CC16 in the association between BMI and clinical asthma measures; 21.8% of its total effect in BMI’s association with airway hyperresponsiveness of healthy subjects (p = 0.09), 26.4% with asthma severity (p = 0.030), and 23% with the required dose of inhaled corticosteroid (p = 0.042). In logistic regression analysis, 1-SD decrease in serum CC16 levels of asthma patients was associated with 87% increased odds for high dose ICS requirement (p < 0.001).

Conclusions

We demonstrate that airway/circulating CC16, which is inversely associated with BMI, may mediate development and severity in overweight/obese asthma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02038-1.

Association of longitudinal changes in quality of life with comorbidities and exacerbations in patients with severe asthma

BACKGROUND

Quality of life (QoL) assessment is important in the management of severe asthma, and comorbidities and/or exacerbations may affect longitudinal QoL. However, there are few reports on the longitudinal assessment of QoL in patients with asthma over multiple years and its related factors. This study aimed to clarify the relationship of longitudinal changes in QoL with comorbidities and/or exacerbations during a prolonged observation period in patients with severe asthma.

METHODS

A total of 105 subjects who participated in the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) with a six-year follow-up were analyzed. QoL was assessed annually, using the Standardized Asthma Quality of Life Questionnaire, and the subjects were divided into three groups: (1) persistently good QoL, (2) persistently poor QoL, and (3) fluctuating QoL. Assessed comorbidities comprised depression, gastroesophageal reflux disease, and excessive daytime sleepiness (EDS), a key symptom of obstructive sleep apnea.

RESULTS

Of 105 subjects with severe asthma, 53 (50%) were classified in the persistently good QoL group, 10 (10%) in the persistently poor QoL group, and 42 (40%) in the fluctuating QoL group. The persistently poor QoL group was associated with shorter time to hospitalization due to exacerbation and the presence of multiple comorbidities. In addition, the presence of EDS was an independent contributor to the fluctuating QoL group compared to the persistently good QoL group.

CONCLUSIONS

The presence of multiple comorbidities and hospitalization due to exacerbation contribute to longitudinal changes in QoL in patients with severe asthma.

Cigarette Smoking and Asthma

Globally, around half the adult asthma population are current or former cigarette smokers. Cigarette smoking and asthma interact to induce an "asthma-smoking phenotype(s)," which has important implications for diagnosis, pathogenic mechanisms, and management. The lack of progress in understanding the effects of smoking on adults with asthma is due in part to their exclusion from most investigative studies and large clinical trials. In this review, we summarize the adverse clinical outcomes associated with cigarette smoking in asthma, highlight challenges in diagnosing asthma among cigarette smokers with chronic respiratory symptoms, particularly in older individuals with a long-standing smoking history, and review pathogenic mechanisms involving smoking- and asthma-related airway inflammation, tissue remodeling, corticosteroid insensitivity, and low-grade systemic inflammation. We discuss the key components of management including the importance of smoking cessation strategies, evidence for the effectiveness of the Global Initiative for Asthma recommendations on treatment in cigarette smokers, and the role of treatable traits such as type 2 eosinophilic airway inflammation. Lastly, we provide an algorithm to aid clinicians to manage current and former smokers with asthma. In the future, controlled and pragmatic trials in real-world populations should include cigarette smokers with asthma to provide an evidence base for treatment recommendations.

Large-scale plasma proteomics can reveal distinct endotypes in chronic obstructive pulmonary disease and severe asthma

BACKGROUND

Chronic airway diseases including chronic obstructive pulmonary disease (COPD) and asthma are heterogenous in nature and endotypes within are underpinned by complex biology. This study aimed to investigate the utility of proteomic profiling of plasma combined with bioinformatic mining, and to define molecular endotypes and expand our knowledge of the underlying biology in chronic respiratory diseases.

METHODS

The plasma proteome was evaluated using an aptamer-based affinity proteomics platform (SOMAscan®), representing 1238 proteins in 34 subjects with stable COPD and 51 subjects with stable but severe asthma. For each disease, we evaluated a range of clinical/demographic characteristics including bronchodilator reversibility, blood eosinophilia levels, and smoking history. We applied modified bioinformatic approaches used in the evaluation of RNA transcriptomics.

RESULTS

Subjects with COPD and severe asthma were distinguished from each other by 365 different protein abundancies, with differential pathway networks and upstream modulators. Furthermore, molecular endotypes within each disease could be defined. The protein groups that defined these endotypes had both known and novel biology including groups significantly enriched in exosomal markers derived from immune/inflammatory cells. Finally, we observed associations to clinical characteristics that previously have been under-explored.

CONCLUSION

This investigational study evaluating the plasma proteome in clinically-phenotyped subjects with chronic airway diseases provides support that such a method can be used to define molecular endotypes and pathobiological mechanisms that underpins these endotypes. It provided new concepts about the complexity of molecular pathways that define these diseases. In the longer term, such information will help to refine treatment options for defined groups.

Overweight improves long-term survival in Japanese patients with asthma

BACKGROUND

Obesity is a risk factor for severe and difficult-to-treat asthma. However, the impact of different physiques on long-term outcomes is poorly understood. We aimed to investigate the correlation between obesity and asthma-associated long-term mortality in Japanese adults.

METHODS

From the data on 3146 individuals with air pollution-related respiratory diseases in the Omuta City Air Pollution-Related Health Damage Cohort Program, 697 adult patients with asthma were analyzed. Hazard ratios for long-term all-cause and respiratory disease -related mortality were compared in patients with different physiques using the Cox proportional hazard models. The classification of physiques was based on the WHO obesity criteria.

RESULTS

Of the 697 patients, 439 died during the median observation period of 26.3 years. The number (% of total) of underweight, normal-weight, pre-obese, and obese class I-III individuals were 75 (10.8%), 459 (65.9%), 140 (20.1%), and 23 (3.3%), respectively. The Cox proportional hazard model (adjusted hazard ratio [95% confidence interval], P value) showed that pre-obese group had a significantly reduced risk for all-cause (0.65 [0.51 to 0.83], P < 0.05) and respiratory disease (0.55 [0.37 to 0.81], P < 0.05)-related mortality related to normal-weight group.

CONCLUSIONS

Our cohort program demonstrated that being slightly overweight may reduce the risk of long-term mortality in patients with asthma. However, the influence of obesity on long-term outcomes remains unclear in asthma, because of the small number of obese patients included in our study. Our findings suggest that interventions, including nutrition and exercises, should be provided to Japanese patients with asthma.

Annual Fractional Exhaled Nitric Oxide Measurements and Exacerbations in Severe Asthma

Purpose

Fractional exhaled nitric oxide (FENO) reflects eosinophilic inflammation of the airways. However, the significance of longitudinal assessment of FENO, including its variability, in the clinical course of severe asthma remains unclear. The aim of this study is to examine the association between long-term changes in FENO and the development of exacerbations in severe asthma.

Patients and Methods

Among the severe asthma patients enrolled in the Hokkaido Severe Asthma Cohort Study, 100 patients with severe asthma who completed a 3-year follow-up in which FENO was measured annually were included. According to the FENO level at baseline, 1 year, and 2 years, the patients were classified into three groups: the sustained high group (≥50 ppb at all three visits), the sustained low group (<25 ppb at all three visits), and the intermediate group (other). Subjects in the intermediate group were further classified into two groups based on the median value of the coefficient of variation (CV) of FENO during the 3 years (high CV and low CV intermediate groups).

Results

The sustained high group experienced shorter exacerbation-free survival and more frequent exacerbations than the sustained low group (median number of exacerbation events, 3 vs 0, p = 0.01). In the intermediate group, the high CV group experienced shorter exacerbation-free survival than the low CV group, and the CV of FENO was an independent contributing factor to the development of exacerbations.

Conclusion

Persistence of FENO above 50 ppb over the years as well as the presence of large variations in FENO levels was associated with the development of exacerbations in patients with severe asthma.

Adult-onset eosinophilic airway diseases

Eosinophilic airway inflammation is one of the cardinal features of allergic airway diseases such as atopic asthma and allergic rhinitis. These childhood-onset conditions are mediated by allergen and allergen-specific IgE and often accompanied by other allergic diseases including food allergy and eczema. They can develop consecutively in the same patient, which is referred to as an allergic march. In contrast, some phenotypes of asthma, nonsteroidal anti-inflammatory drugs-exacerbated airway disease (N-ERD), chronic rhinosinusitis with nasal polyps (CRSwNP)/eosinophilic CRS and allergic bronchopulmonary aspergillosis/mycosis (ABPA/ABPM) are adult-onset airway diseases, which are characterized by prominent peripheral blood eosinophilia. Most of these conditions, except for ABPA/ABPM, are nonatopic, and the coexistence of multiple diseases, including an adult-onset eosinophilic systemic disease, eosinophilic granulomatosis with polyangiitis (EGPA), is common. In this review, we focus on eosinophil biology, genetics and clinical characteristics and the pathophysiology of adult-onset eosinophilic asthma, N-ERD, CRSwNP/eosinophilic CRS, ABPA/ABPM and EGPA, while exploring the common genetic, immunological and pathological conditions among these adult-onset eosinophilic diseases.

Real-life safety and efficacy of omalizumab in Japanese patients with severe allergic asthma who were subjected to dosing table revision or expansion: A post-marketing surveillance

BACKGROUND

Omalizumab is an anti-immunoglobulin E monoclonal antibody approved for patients with severe allergic asthma in Japan. With regard to omalizumab dosage in Japanese adults with severe allergic asthma in clinical practice settings, this post-marketing surveillance evaluated safety and efficacy of the dosing table revision (DTR) based on a dosing regimen of omalizumab administration every 4 weeks dosing regimen and dosing table expansion (DTE) for patients with baseline IgE levels >700 IU/mL.

METHODS

This 52-week, multicenter study, conducted from September 2013 to November 2018, evaluated omalizumab safety outcomes including adverse events (AEs), serious AEs (SAEs), adverse drug reactions (ADRs), efficacy outcomes including Global Evaluation of Treatment Effectiveness (GETE), change in oral corticosteroid dose, and asthma exacerbation-related events such as hospitalization, emergency room visits, and worsening of symptoms.

RESULTS

Of the 405 patients registered in the study, safety was evaluated in 392 and efficacy in 390. The mean age of patients was 58.5 years and 58.7% were women. In total, 41.3% of the patients were subjected to DTE and 58.7% to DTR. In the safety dataset, 6.6% experienced an ADR, 32.9% experienced an AE, and 16.1% experienced an SAE. In the efficacy dataset, 63.3% of patients at Week 16 and 63.5% at Week 52 had an 'effective' or 'good' GETE score. Omalizumab was associated with a reduction in worsening of asthma symptoms requiring systemic corticosteroids and frequency of hospitalization. All outcomes were comparable among the DTE and DTR subgroups.

CONCLUSION

The findings from this study support the safety and efficacy of omalizumab administered based on the revised and expanded dosing table in Japanese patients with severe allergic asthma.

Role of serum periostin in the management of asthma and its comorbidities

Type-2 airway inflammation is a major characteristic of asthma. Assessing its degree of severity is, therefore, essential in asthma management. Periostin, a matricellular protein belonging to the fasciclin family, is a key molecule linking type-2 airway inflammation and airway remodeling. Fortunately, periostin can be detected in the blood and used to provide sustaining airway information on type-2 inflammation and remodeling. Serum periostin is elevated in the eosinophilic/type 2 subtype of severe asthma, and its levels remain relatively stable and reflect genetic backgrounds. This suggests that serum periostin may serve as a marker of geno-endophenotype with type-2 airway inflammation and thus could be a predictive marker of the long-term prognosis of asthma under treatment. As expected, serum periostin is particularly elevated in comorbidities associated with the eosinophilic/type 2 subtype of severe asthma, including eosinophilic chronic rhinosinusitis, aspirin-exacerbated respiratory diseases, allergic bronchopulmonary aspergillosis, and eosinophilic granulomatosis with polyangiitis. Conversely, serum periostin levels are relatively lower in the overweight/obese. Serum periostin measurements may help to significantly improve the management of patients with severe asthma.

Defining severe obstructive lung disease in the biologic era: an endotype-based approach

Severe obstructive lung disease, which encompasses asthma, chronic obstructive pulmonary disease (COPD) or features of both, remains a considerable global health problem and burden on healthcare resources. However, the clinical definitions of severe asthma and COPD do not reflect the heterogeneity within these diagnoses or the potential for overlap between them, which may lead to inappropriate treatment decisions. Furthermore, most studies exclude patients with diagnoses of both asthma and COPD. Clinical definitions can influence clinical trial design and are both influenced by, and influence, regulatory indications and treatment recommendations. Therefore, to ensure its relevance in the era of targeted biologic therapies, the definition of severe obstructive lung disease must be updated so that it includes all patients who could benefit from novel treatments and for whom associated costs are justified. Here, we review evolving clinical definitions of severe obstructive lung disease and evaluate how these have influenced trial design by summarising eligibility criteria and primary outcomes of phase III randomised controlled trials of biologic therapies. Based on our findings, we discuss the advantages of a phenotype- and endotype-based approach to select appropriate populations for future trials that may influence regulatory approvals and clinical practice, allowing targeted biologic therapies to benefit a greater proportion and range of patients. This calls for co-ordinated efforts between investigators, pharmaceutical developers and regulators to ensure biologic therapies reach their full potential in the management of severe obstructive lung disease.

Severe asthma phenotypes in patients controlled with omalizumab: A real-world study

BACKGROUND

The appropriate identification of asthma phenotypes of responders to omalizumab would optimize the selection of treatment.

OBJECTIVE

To describe the most frequent clinical phenotypes in patients with severe asthma responding to omalizumab and their clinical and pulmonary function improvement.

METHODS

This was an observational, retrospective, multicenter study. Adult patients with severe asthma, who achieved good control after the first year of treatment with omalizumab were included. Omalizumab was prescribed according to clinical routine practice. Responders were assigned to one pre-established phenotype based on the most predominant one before they had started treatment with omalizumab, all according to the physician's criteria. Data about asthma symptoms, number of non-severe asthma exacerbations, medication intake (inhaled and oral corticosteroids and rescue medication), lung function, high fractional exhaled nitric oxide (FeNO) and peripheral eosinophils counts were recorded.

RESULTS

Among the 345 patients included, the main phenotypes were severe asthma with frequent exacerbations (29.9%), early-onset allergic asthma (23.8%), severe steroid-dependent asthma (18.8%), and severe eosinophilic asthma (13.6%). Clinical and respiratory changes observed after first year of treatment with omalizumab included: reduction in asthma symptoms, reduction in the use and dose of corticosteroids and need for rescue therapy, improvement of pulmonary function, reduction in the number of episodes of non-severe asthma exacerbations regardless of the duration of severe disease since the diagnosis. Increased blood levels of peripheral eosinophils and high FeNO levels were found at baseline.

CONCLUSION

Several heterogeneous severe asthma phenotypes were observed as good responders to omalizumab.

Asthma phenotypes in a multi-ethnic Asian cohort

BACKGROUND

Identification of asthma phenotypes facilitates our understanding of asthma pathobiologies. Phenotypes observed in homogenous Asian cohorts have distinct differences from those described in Caucasian cohorts, suggesting that ethnicity may influence phenotypic expression. Phenotypic clusters in a multi-ethnic Southeast Asian cohort have not been described before, and direct comparisons of these clusters within a single study may reveal how ethnicity affects phenotypic expression.

METHODS

Six hundred and thirty adult asthma patients from two healthcare institutions in Singapore were randomly assigned in a 2:1 fashion to a test and validation cohort. Latent class analysis was performed on both cohorts using age of asthma onset, sex, ethnicity, smoking status, body mass index, lung function, blood eosinophil count, asthma control test score, and exacerbation frequency as input variables. Phenotypic clusters between the test and validation cohorts were compared RESULTS: Three clusters were identified in both the test and validation cohorts, with corresponding clusters of each cohort sharing similar characteristics. Ethnic representation and asthma control were significantly different between clusters. Cluster one comprised Chinese females with late-onset asthma and the best asthma control. Cluster two comprised non-Chinese females with obesity and the worst asthma control. Cluster three was multi-ethnic with the greatest proportion of atopic patients.

CONCLUSION

We identified three phenotypic clusters in our multi-ethnic Southeast Asian population, with distinct differences in ethnicity which may be attributable to inherent differences in baseline characteristics among ethnic groups.

Cluster analysis to define distinct clinical phenotypes among septic patients with bloodstream infections

Prior attempts at identifying outcome determinants associated with bloodstream infection have employed a priori determined classification schemes based on readily identifiable microbiology, infection site, and patient characteristics. We hypothesized that even amongst this heterogeneous population, clinically relevant groupings can be described that transcend old a priori classifications.We applied cluster analysis to variables from three domains: patient characteristics, acuity of illness/clinical presentation and infection characteristics. We validated our clusters based on both content validity and predictive validity.Among 3715 patients with bloodstream infections from Barnes-Jewish Hospital (2008-2015), the most stable cluster arrangement occurred with the formation of 4 clusters. This clustering arrangement resulted in an approximately uniform distribution of the population: Cluster One "Surgical Outside Hospital Transfers" (21.5%), Cluster Two "Functional Immunocompromised Patients" (27.9%), Cluster Three "Women with Skin and Urinary Tract Infection" (28.7%) and Cluster Four "Acutely Sick Pneumonia" (21.8%). Staphylococcus aureus distributed primarily to Clusters Three (40%) and Four (25%), while nonfermenting Gram-negative bacteria grouped mainly in Clusters Two and Four (31% and 30%). More than half of the pneumonia cases occurred in Cluster Four. Clusters One and Two contained 33% and 31% respectively of the individuals receiving inappropriate antibiotic administration. Mortality was greatest for Cluster Four (33.8%, 27.4%, 19.2%, 44.6%; P < .001), while Cluster One patients were most likely to be discharged to a nursing home.Our results support the potential for machine learning methods to identify homogenous groupings in infectious diseases that transcend old a priori classifications. These methods may allow new clinical phenotypes to be identified potentially improving the severity staging and development of new treatments for complex infectious diseases.

Severe asthma in Japan

The characteristic phenotype of severe asthma in Japan seems to be distilled into the following two features: low incidence of obesity and high prevalence of patients with type 2 inflammation. Only 5-7% of Japanese severe asthma patients had a body mass index (BMI) ≥30 kg/m², and more than 80% of patients with severe asthma exhibited type 2 inflammation. Although the relationship between obesity and non-type 2 inflammation is complex, the low incidence of obesity might explain the prevalence of type 2 inflammation. Some asthma cohorts in Japan have investigated the roles of type 2 biomarkers extensively, including periostin, to identify a severe phenotype, suggesting the utility of combining biomarkers to identify an exacerbation-prone subgroup. Although the prevalence of severe asthma is comparable to Western countries, the rate of asthma death and disease burden seems to be lower in Japan. These trends might be due to the system of public health insurance for the whole nation, leading to good access to hospital and asthma specialists due to the geographically narrow country. In this review article, we will discuss the definition, epidemiology, comorbidities, biomarkers, specific phenotype, and current treatment for severe asthma in Japan.

The prevalence and disease burden of severe eosinophilic asthma in Japan

Background: There are limited data on the prevalence and burden of severe eosinophilic asthma (SEA) both in Japan and globally. This study aimed to assess the prevalence and burden of SEA in Japan. Methods: This study was a retrospective, observational cohort analysis using health records or health insurance claims from patients with severe asthma treated at Kyoto University Hospital. The primary outcome was the prevalence of SEA, defined as a baseline blood eosinophil count ≥300 cells/μL. Secondary outcomes included frequency and risk factors of asthma exacerbations, and asthma-related healthcare resource utilization and costs. Results: Overall, 217 patients with severe asthma were included; 160 (74%) had eosinophil assessments. Of these, 97cases (61%), 54cases (34%), and 33cases (21%) had a blood eosinophil count ≥150, ≥300, and ≥500 cells/μL, respectively. Proportion of SEA was 34%. Blood eosinophil count was not associated with a significantly increased frequency of exacerbations. In the eosinophilic group, lower % forced expiratory volume in 1 second and higher fractional exhaled nitric oxide were predictive risk factors, while the existence of exacerbation history was a predictive risk factor for asthma exacerbations in the non-eosinophilic group. Severe asthma management cost was estimated as ¥357,958/patient-year, and asthma exacerbations as ¥26,124/patient-year. Conclusions: Approximately, one-third of patients with severe asthma in Japan have SEA. While risk factors for exacerbations differed between SEA and severe non-eosinophilic asthma, both subgroups were associated with substantial disease and economic burden. From subgroup analysis, blood eosinophil counts could be an important consideration in severe asthma management.

Identification and prospective stability of electronic nose (eNose)-derived inflammatory phenotypes in patients with severe asthma

BACKGROUND

Severe asthma is a heterogeneous condition, as shown by independent cluster analyses based on demographic, clinical, and inflammatory characteristics. A next step is to identify molecularly driven phenotypes using "omics" technologies. Molecular fingerprints of exhaled breath are associated with inflammation and can qualify as noninvasive assessment of severe asthma phenotypes.

OBJECTIVES

We aimed (1) to identify severe asthma phenotypes using exhaled metabolomic fingerprints obtained from a composite of electronic noses (eNoses) and (2) to assess the stability of eNose-derived phenotypes in relation to within-patient clinical and inflammatory changes.

METHODS

In this longitudinal multicenter study exhaled breath samples were taken from an unselected subset of adults with severe asthma from the U-BIOPRED cohort. Exhaled metabolites were analyzed centrally by using an assembly of eNoses. Unsupervised Ward clustering enhanced by similarity profile analysis together with K-means clustering was performed. For internal validation, partitioning around medoids and topological data analysis were applied. Samples at 12 to 18 months of prospective follow-up were used to assess longitudinal within-patient stability.

RESULTS

Data were available for 78 subjects (age, 55 years [interquartile range, 45-64 years]; 41% male). Three eNose-driven clusters (n = 26/33/19) were revealed, showing differences in circulating eosinophil (P = .045) and neutrophil (P = .017) percentages and ratios of patients using oral corticosteroids (P = .035). Longitudinal within-patient cluster stability was associated with changes in sputum eosinophil percentages (P = .045).

CONCLUSIONS

We have identified and followed up exhaled molecular phenotypes of severe asthma, which were associated with changing inflammatory profile and oral steroid use. This suggests that breath analysis can contribute to the management of severe asthma.

Impact of Abdominal Visceral Adiposity on Adult Asthma Symptoms

BACKGROUND

Previous studies have shown the association of anthropometric measures with poor asthma symptoms, especially among women. However, the potential influence of visceral adiposity on asthma symptoms has not been investigated well.

OBJECTIVE

In this study, we have evaluated whether visceral adiposity is related to poor adult asthma symptoms independent of anthropometric measures and sex. If this relationship presented, we investigated whether it is explained by influence on pulmonary functions and/or obesity-related comorbidities.

METHODS

We analyzed data from 206 subjects with asthma from Japan. In addition to anthropometric measures (body mass index and waist circumference), abdominal visceral and subcutaneous fat were assessed by computed tomography scan. Quality of life was assessed using the Japanese version of the Asthma Quality of Life Questionnaire.

RESULTS

All obesity indices had inverse association with reduced asthma quality of life among females. However, only the visceral fat area showed a statistical inverse association with Asthma Quality of Life Questionnaire in males. Only abdominal visceral fat was associated with higher gastroesophageal reflux disease and depression scores. Although all obesity indices showed inverse association with functional residual capacity, only visceral fat area had a significant inverse association with FEV₁ % predicted, independent of other obesity indices.

CONCLUSIONS

Regardless of sex, abdominal visceral fat was associated with reduced asthma quality of life independent of other obesity indices, and this may be explained by the impact of abdominal visceral fat on reduced FEV₁ % predicted and higher risk for gastroesophageal reflux disease and depression. Therefore, visceral adiposity may have more clinical influence than any other obesity indices on asthma symptoms.

A suitable protocol for measuring alveolar nitric oxide in asthma with differing severity to assess peripheral airways inflammation

OBJECTIVE

Extended nitric oxide (NO) analysis offers the partitioned monitoring of inflammation in central and peripheral airways. Different mathematical models are used to estimate pulmonary NO dynamics in asthma with variable results and limitations. We aimed to establish a protocol for extended NO analysis in patients with differing asthma severity.

METHODS

Forty patients with stable asthma and 25 matched control subjects were recruited. Exhaled NO was measured at constant flow rates between 10 and 300 mL/s. Twelve controls performed NO measurements weekly for 4 weeks.

RESULTS

The proportions of patients with technically acceptable measurements at 10-30-50-100-150-200-250-300 mL/s exhalation flow rates were 8-58-100-98-98-95-90-80%, respectively. Alveolar NO (CANO) and total flux of NO in the conducting airways (JawNO) were calculated with the linear method from NO values measured at 100-150-200-250 mL/s exhalation flows. The mean intrasubject bias for JawNO and CANO in controls was 0.16 nL/s and 0.85 ppb, respectively. Both JawNO (1.31/0.83-2.97/vs. 0.70/0.54-0.87/nL/s, p < 0.001) and CANO (4.08/2.63-7.16/vs. 2.42/1.83-2.89/ppb, p < 0.001) were increased in patients with asthma compared to controls. In patients, CANO correlated with RV/TLC (r = 0.58, p < 0.001), FEF_25-75% (p = 0.02, r = -0.36) and DL,CO (r = -0.46, p = 0.004). JawNO was not related to lung function parameters.

CONCLUSIONS

Calculation of alveolar NO concentration with the linear method from values obtained at medium flow rates (100-250 mL/s) is feasible even in asthmatic patients with severe airflow limitation and may provide information on small airways dysfunction in asthma.

Predictors of Asthma/COPD Overlap in FDNY Firefighters With World Trade Center Dust Exposure: A Longitudinal Study

BACKGROUND

Previously healthy firefighters with World Trade Center (WTC) dust exposure developed airway disease. Risk factors for irritant-associated asthma/COPD overlap are poorly defined.

METHODS

This study included 2,137 WTC-exposed firefighters who underwent a clinically indicated bronchodilator pulmonary function test (BD-PFT) between 9/11/2001 and 9/10/2017. A post-BD FEV₁ increase of > 12% and 200 mL from baseline defined asthma, and a post-BD FEV₁/FVC ratio < 0.7 identified COPD cases. Participants who met both criteria had asthma/COPD overlap. Eosinophil levels were measured on screening blood tests performed shortly after 9/11/2001 and prior to BD-PFT; a subgroup of participants also had serum IgE and 21 cytokines measured (n = 215). Marginal Cox regression models for multiple events assessed the associations of eosinophil levels or serum biomarkers with subsequent diagnosis, with age, race, smoking, WTC exposure, first post-9/11 FEV₁/FVC ratio, and BMI included as covariates.

RESULTS

BD-PFT diagnosed asthma/COPD overlap in 99 subjects (4.6%), isolated-asthma in 202 (9.5%), and isolated-COPD in 215 (10.1%). Eosinophil concentration ≥ 300 cells/μL was associated with increased risk of asthma/COPD overlap (hazard ratio [HR], 1.85; 95% CI, 1.16-2.95) but not with isolated-asthma or isolated-COPD. Serum IL-4 also predicted asthma/COPD overlap (HR, 1.51 per doubling of cytokine concentration; 95% CI, 1.17-1.95). Greater IL-21 concentration was associated with both isolated-asthma and isolated-COPD (HRs of 1.73 [95% CI, 1.27-2.35] and 2.06 [95% CI, 1.31-3.23], respectively).

CONCLUSIONS

In WTC-exposed firefighters, elevated blood eosinophil and IL-4 levels are associated with subsequent asthma/COPD overlap. Disease-specific T-helper cell type 2 biomarkers present years before diagnosis suggest patient-intrinsic predisposition to irritant-associated asthma/COPD overlap.

Serum periostin is associated with body mass index and allergic rhinitis in healthy and asthmatic subjects

BACKGROUND

Many studies have attempted to clarify the factors associated with serum periostin levels in asthmatic patients. However, these results were based on studies of subjects mainly characterized by high eosinophil counts, which may present as an obstacle for clarification in the identification of other factors associated with serum periostin levels. The aim of this study was to determine the factors associated with serum periostin levels in healthy subjects. We also assessed some factors in asthmatic subjects to confirm their extrapolation for management of asthma.

METHODS

Serum periostin levels were measured in 230 healthy subjects. Clinical factors of interest included body mass index (BMI) and allergic rhinitis (AR). Additionally, we confirmed whether these factors were associated with serum periostin in 206 asthmatic subjects. We further evaluated several obesity-related parameters, such as abdominal fat distribution and adipocytokine levels.

RESULTS

Smoking status, blood eosinophil count, total immunoglobulin E, and the presence of AR were associated with serum periostin in healthy subjects. There was a negative association between BMI and serum periostin in both healthy and asthmatic subjects, while there was a tendency of a positive association with AR in asthmatic subjects. There were no differential associations observed for subcutaneous and abdominal fat in relation to serum periostin in asthmatic subjects. Serum periostin was significantly associated with serum levels of adiponectin, but not with leptin.

CONCLUSIONS

Our results provided clarity as to the factors associated with serum periostin levels, which could be helpful in the interpretation of serum periostin levels in clinical practice.

Real-world safety and efficacy of omalizumab in patients with severe allergic asthma: A long-term post-marketing study in Japan

BACKGROUND

Omalizumab (anti-IgE monoclonal antibody) is an approved add-on therapy for Japanese patients with severe allergic asthma. As directed by the Ministry of Health, Labor and Welfare Japan, a post-marketing surveillance (PMS) study on omalizumab was conducted between 2009 and 2017.

METHODS

The PMS observed safety and efficacy of omalizumab in patients treated with open-label omalizumab for 52 weeks (with optional 2-year extension period). Primary safety outcomes included incidence and severity of adverse events (AEs) and adverse drug reactions (ADRs). Primary efficacy outcomes included physician-assessed global evaluation of treatment effectiveness (GETE). Asthma-exacerbation-related events including requirement for additional systemic steroid therapy, hospitalization, emergency room visits, unscheduled doctor visits, and absenteeism were also evaluated.

RESULTS

Of 3893 patients registered, 3620 (age [mean ± SD] 59.3 ± 16.11 years) were evaluated for 52 weeks; 44.12% were aged ≥65 years and 64.45% were women. Overall, 32.24% reported AEs and 15.30% reported serious AEs. ADRs were seen in 292 (8.07%) patients. GETE results showed that the majority of patients experienced clinical improvements (58.29% at 16 weeks and 62.40% at 52 weeks). Nearly half of all patients (47.96%) were free from asthma exacerbations after therapy. Omalizumab also reduced all events related to asthma exacerbations. No specific ADRs were observed in the elderly population.

CONCLUSIONS

This post-marketing study confirmed the clinically meaningful benefits of omalizumab in a majority of patients from Japan, and showed safety and efficacy in a real-life clinical setting to be consistent with previous reports.

Transfer coefficients better reflect emphysematous changes than carbon monoxide diffusing capacity in obstructive lung diseases

The overlap between asthma and chronic obstructive pulmonary disease (COPD) has attracted the interest of pulmonary physicians; thus, measurement of carbon monoxide diffusion capacity (DLco) and/or transfer coefficients (Kco, DLco/V_A) may become valuable in clinical settings. How these parameters behave in chronic obstructive lung diseases is poorly understood. We predicted that Kco might more accurately reflect emphysematous changes in the lungs than DLco. We examined DLco and Kco in nonsmokers and smokers with asthma and investigated their relationships with forced expiratory volume in 1 s (%FEV₁) by group. We then selected nonsmokers (As-NS) and smokers with asthma (As-Sm) in both groups and those with COPD while controlling for the degree of airflow limitation across groups. Emphysema volumes [%lung attenuation volume (%LAV)] and percentage of cross-sectional area of small pulmonary vessels <5 mm² (%CSA_<5) were measured by computed tomography. In As-NS, %Kco was significantly higher when FEV₁% was reduced, but such a correlation was not seen in As-Sm. %Kco successfully differentiated among the three groups when airflow limitation levels were matched. However, %DLc, was significantly reduced only in patients with COPD. Both %LAV and %CSA_<5 were better correlated with %Kco than with %DLco. There was discordance between %DL_CO and %Kco in As-Sm, which was not seen in As-NS. Overall, %Kco better reflects emphysematous changes in obstructive lung diseases than %DLco. NEW & NOTEWORTHY Despite differing behaviors of %Kco and %DLco in several diseases, the characteristics of these parameters have not been fully examined in smokers with asthma. Here, we demonstrated that %Kco is a more sensitive parameter of pathophysiology, better reflecting emphysematous changes in chronic obstructive lung diseases overall, compared with %DLco. Thus, more precise interpretations of %DLco and %Kco may provide clues for understanding the pathophysiology of obstructive lung diseases.

Asthma Phenotypes Defined From Parameters Obtained During Recovery From a Hospital-Treated Exacerbation

BACKGROUND

Asthma is a heterogeneous disease with diverse clinical manifestations and inflammatory pathologies that is punctuated by exacerbations.

OBJECTIVE

To describe the clinical and inflammatory characteristics of patients with asthma treated in hospital for an acute exacerbation.

METHODS

Data from 320 adult patients receiving treatment for an acute exacerbation of asthma were obtained. In 218 patients with complete data, we used the Ward hierarchical clustering to obtain clusters. Pulmonary function, blood cell counts, sputum cell counts, serum IgE levels, and fractional exhaled nitric oxide were measured on hospital admission. We selected 13 variables with which we performed the Ward minimum-variance hierarchical clustering.

RESULTS

Four clusters were defined. Clusters 1 (24.5%) and 3 (36.7%) were characterized by predominantly female patients with asthma with sputum neutrophilia, with cluster 1 associated with a small degree of airflow obstruction and early-onset asthma and cluster 3 with a moderate degree of reduction in FEV₁. Clusters 2 (22.0%) and 4 (16.5%) were associated with high sputum eosinophilia and severe airflow obstruction. Cluster 4 was made exclusively of male smoking subjects, whereas cluster 2 was made up of predominantly female nonsmoking subjects with the worst FEV₁, forced expiratory flow at 25% to 75% of forced vital capacity (% predicted), and partial pressure of oxygen in arterial blood on admission. There were no differences between clusters in terms of atopy, serum IgE, prevalence of nasal disease, dose of maintenance inhaled corticosteroids, or oral/systemic corticosteroid use and asthma exacerbations.

CONCLUSIONS

The clusters during recovery from an exacerbation of asthma were distinguished by airflow obstruction and a neutrophilic, eosinophilic, or mixed inflammation. Eosinophilic inflammation was found in smoking and nonsmoking patients with asthma during an exacerbation.