American Thoracic Society/National Heart, Lung, and Blood Institute Asthma-Chronic Obstructive Pulmonary Disease Overlap Workshop Report

Airway inflammation in COPD: progress to precision medicine

Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality worldwide, and its prevalence is increasing. Airway inflammation is a consistent feature of COPD and is implicated in the pathogenesis and progression of COPD, but anti-inflammatory therapy is not first-line treatment. The inflammation has many guises and phenotyping this heterogeneity has revealed different patterns. Neutrophil-associated COPD with activation of the inflammasome, T1 and T17 immunity is the most common phenotype with eosinophil-associated T2-mediated immunity in a minority and autoimmunity observed in more severe disease. Biomarkers have enabled targeted anti-inflammatory strategies and revealed that corticosteroids are most effective in those with evidence of eosinophilic inflammation, whereas, in contrast to severe asthma, response to anti-interleukin-5 biologicals in COPD has been disappointing, with smaller benefits for the same intensity of eosinophilic inflammation questioning its role in COPD. Biological therapies beyond T2-mediated inflammation have not demonstrated benefit and in some cases increased risk of infection, suggesting that neutrophilic inflammation and inflammasome activation might be largely driven by bacterial colonisation and dysbiosis. Herein we describe current and future biomarker approaches to assess inflammation in COPD and how this might reveal tractable approaches to precision medicine and unmask important host-environment interactions leading to airway inflammation.

Prevalence of COPD among workers with work-related asthma

Objective: Concurrent asthma and chronic obstructive pulmonary disease (COPD) diagnoses occur in 15%-20% of patients, and have been associated with worse health outcomes than asthma or COPD alone. Work-related asthma (WRA), asthma that is caused or made worse by exposures in the workplace, is characterized by poorly controlled asthma. The objective of this study was to assess the proportion of ever-employed adults (≥18 years) with current asthma who have been diagnosed with COPD, by WRA status.Methods: Data from 23 137 respondents to the 2012-2014 Behavioral Risk Factor Surveillance System Asthma Call-back Survey from 31 states and the District of Columbia were examined. Logistic regression was used to calculate adjusted prevalence ratios (PRs), examining six disjoint categories of WRA-COPD overlap with non-WRA/no COPD as the referent category.Results: An estimated 51.9% of adults with WRA and 25.6% of adults with non-WRA had ever been diagnosed with COPD. Adults with WRA/COPD were more likely than those with non-WRA/no COPD to have an asthma attack (PR = 1.77), urgent treatment for worsening asthma (PR = 2.85), an asthma-related emergency room visit (PR = 4.21), overnight stay in a hospital because of asthma (PR = 6.57), an activity limitation on 1-13 days (PR = 2.01) or ≥14 days (PR = 5.02), and very poorly controlled asthma (PR = 3.22).Conclusions: COPD was more frequently diagnosed among adults with WRA than those with non-WRA, and adults diagnosed with both WRA and COPD appear to have more severe adverse asthma outcomes than those with non-WRA and no COPD.

Metabolomic signatures of asthma-COPD overlap (ACO) are different from asthma and COPD

INTRODUCTION

Asthma-chronic obstructive pulmonary disease (COPD) overlap, termed as ACO, is a complex heterogeneous disease without any clear diagnostic or therapeutic guidelines. The pathophysiology of the disease, its characteristic features, and existence as a unique disease entity remains unclear. Individuals with ACO have a faster lung function decline, more frequent exacerbations, and worse quality of life than those with COPD or asthma alone.

OBJECTIVES

The present study aims to determine whether ACO has a distinct metabolic profile in comparison to asthma and COPD.

METHODS

Two different groups of patients were recruited as discovery (D) and validation (V) cohorts. Serum samples obtained from moderate and severe asthma patients diagnosed as per GINA guidelines [n = 34(D); n = 32(V)], moderate and severe COPD cases identified by GOLD guidelines [n = 30(D); 32(V)], ACO patients diagnosed by joint GOLD and GINA guidelines [n = 35(D); 40(V)] and healthy controls [n = 33(D)] were characterized using nuclear magnetic resonance (NMR) spectrometry.

RESULTS

Multivariate and univariate analysis indicated that 12 metabolites [lipid, isoleucine, N-acetylglycoproteins (NAG), valine, glutamate, citric acid, glucose, L-leucine, lysine, asparagine, phenylalanine and histidine] were dysregulated in ACO patients when compared with both asthma and COPD. These metabolites were further validated in a fresh cohort of patients, which again exhibited a similar expression pattern.

CONCLUSIONS

Our findings suggest that ACO has an enhanced energy and metabolic burden associated with it as compared to asthma and COPD. It is anticipated that our results will stimulate researchers to further explore ACO and unravel the pathophysiological complexities associated with the disease.

Physiological and morphological differences of airways between COPD and asthma-COPD overlap

Overlap of asthma and COPD has attracted attention recently. We aimed to clarify physiological and morphological differences of the airways between COPD and asthma–COPD overlap (ACO). Respiratory resistance and reactance and three-dimensional computed tomography data were evaluated in 167 patients with COPD. Among them, 43 patients who fulfilled the diagnosis of asthma were defined as having ACO. Among 124 patients with COPD without ACO, 86 with a comparable smoking history and airflow limitation as those with ACO were selected using propensity score matching (matched COPD). The intraluminal area (Ai) and wall thickness (WT) of third- to sixth-generation bronchi were measured and adjusted by body surface area (BSA; Ai/BSA and WT/√BSA, respectively). Patients with ACO had higher respiratory resistance and reactance during tidal breathing, but a smaller gap between the inspiratory and expiratory phases, compared with matched patients with COPD. Patients with ACO had a greater WT/√BSA in third- to fourth-generation bronchi, smaller Ai/BSA in fifth- to sixth-generation bronchi, and less emphysematous changes than did matched patients with COPD. Even when patients with ACO and those with COPD have a comparable smoking history and fixed airflow limitation, they have different physiological and morphological features of the airways.

A retrospective cohort study evaluating healthcare resource utilization in patients with asthma in Japan

Although the global economic burden of asthma is well described, detailed data regarding Asia, particularly for Japan, are relatively scarce. This retrospective study aims to fill this evidence gap by evaluating asthma-associated healthcare resource utilization (HCRU) and economic burden in Japanese patients aged ≥16 years, identified using anonymized patient data from the Japan Medical Data Center (JMDC) database from April 2009 to March 2015. Asthma severity was classified according to asthma treatment guidelines from the Japanese Society of Allergology. HCRU was calculated based on hospitalizations, emergency room visits, outpatient visits, and prescriptions. Incidence rate ratios (IRRs) for HCRU and per-patient-per-year direct costs were reported. In addition, differences across HCRU and cost variables for severe versus non-severe asthma patients were also compared. Of 541,434 asthma cases identified from the JMDC database during the study period, 54,433 patients who met the inclusion criteria were included in this analysis. HCRU and costs were heavily concentrated within severe asthma, a subgroup comprising 12.7% of total study population. Moreover, patients with severe asthma had significantly higher all-cause hospitalizations, outpatient visits, outpatient prescriptions (IRR [95% CI], 1.60 [1.46–1.76]; 1.43 [1.41–1.45]; 1.24 [1.22–1.25], respectively), and total medical costs (mean ± SD costs, US$ 4345 ± 11,104 versus US$ 1528 ± 3989, P < 0.001 (t-test); US$ 1 = 110 JPY) compared with those with non-severe asthma. The burden of asthma is significantly and disproportionately concentrated in Japanese severe asthma patients, suggesting clinical failure to achieve adequate disease control. This study highlights the unmet needs for severe asthma in Japan and provides a catalyst for important dialogues in advancing public health.

Compressive air trapping in asthma: effects of age, sex, and severity

Air trapping due to airway closure has been associated with unstable asthma. In addition to airway closure that occurs at lower lung volumes during slow expiration, there may be further closure during a forced expiration because of airway compression. The purpose of this study was to define a reference range from a nonasthmatic population and investigate the characteristics of compressive air trapping in asthma. Spirometry and plethysmography were performed in 117 nonasthmatic subjects (ages 18-87 yr) and 153 asthma subjects (ages 12-72 yr). Air trapping was assessed as residual lung volume and the ratio of forced expiratory vital capacity (FVC) to slow inspiratory vital capacity (iVC) (FVC/iVC). There were no significant age or sex effects on the FVC/iVC ratio in the nonasthmatic subjects, and a fifth percentile lower limit of normal (LLN) of 0.93 was computed. An FVC/iVC ratio less than LLN defined compressive air trapping. Asthma subjects exhibited an age-related decline in the FVC/iVC ratio of 0.0027 per year (P < 0.0001) in a mixed effects model, with additional decreases associated with severe asthma and male sex. FVC/iVC ratios< LLN were infrequent in subjects <30 yr but evident in most asthma subjects >50 yr. Lung residual volumes followed similar patterns of greater elevations in subjects with severe asthma, older age, and male sex. Compressive air trapping occurs frequently in older asthmatics, appearing to be a feature of the natural history of asthma that is greater in severe asthma and men. This component of premature airway closure affects spirometric assessment of airway function and may contribute to asthma symptoms during physical exertion. NEW & NOTEWORTHY Premature airway closure during exhalation is a component of airway obstruction that is associated with asthma severity and instability. Compressive air trapping is airway closure that is more extensive during a forced exhalation than with a slow, passive exhalation. We report that compressive air trapping occurs in most people > 50 yr with asthma, affects men more than women, and persists after bronchodilator treatment. This component of obstruction appears to be part of the natural history of asthma.

Asthma diagnosis in infants and preschool children: a systematic review of clinical guidelines

BACKGROUND AND AIM

The definition and diagnosis of asthma are the subject of controversy that is particularly intense in the case of individuals in the first years of life, due to reasons such as the difficulty of performing objective pulmonary function tests or the high frequency with which the symptoms subside in the course of childhood. Since there is no consensus regarding the diagnosis of asthma in preschool children, a systematic review has been carried out.

MATERIALS AND METHODS

A systematic search was made of the clinical guidelines published in the last 10 years and containing information referred to the concept or diagnosis of asthma in childhood - including the first years of life (infants and preschool children). A series of key questions were established, and each selected guide was analyzed in search of answers to those questions. The review protocol was registered in the international prospective register of systematic reviews (PROSPERO), with registration number CRD42017074872.

RESULTS

Twenty-one clinical guidelines were selected: 10 general guides (children and adults), eight pediatric guides and three guides focusing on preschool children. The immense majority accepted that asthma can be diagnosed from the first years of life, without requiring pulmonary function tests or other complementary techniques. The response to treatment and the exclusion of other alternative diagnoses are key elements for establishing the diagnosis. Only one of the guides denied the possibility of diagnosing asthma in preschool children.

CONCLUSIONS

There is generalized although not unanimous agreement that asthma can be diagnosed in preschool children.

Respiratory Enterovirus (like Parainfluenza Virus) Can Cause Chronic Lung Disease if Protection by Airway Epithelial STAT1 Is Lost

Epithelial barrier cells are proposed to be critical for host defense, and airway epithelial cell capacity for IFN signal transduction is presumed to protect against respiratory viral infection. However, it has been difficult to fully test these concepts given the absence of tools to analyze IFN signaling specific to airway epithelial cells in vivo. To address these issues, we generated a new line of transgenic mice with Cre-driver genes (Foxj1 and Scgb1a1) for a floxed-Stat1 allele (designated Foxj1-Scgb1a1-Cre-Stat1^f/f mice) to target the master IFN signal regulator STAT1 in airway epithelial cells and tested these mice for control of infection because of mouse parainfluenza (Sendai) virus and human enterovirus D68 (EV-D68). Indeed, both types of infections showed increases in viral titers and severity of acute illness in Foxj1-Scgb1a1-Cre-Stat1^f/f mice and conventional Stat1^-/- mice compared with wild-type mice. In concert, the chronic lung disease that develops after Sendai virus infection was also increased in Foxj1-Scgb1a1-Cre-Stat1^f/f and Stat1^{-/ -} mice, marked by airway and adjacent parenchymal immune cell infiltration and mucus production for at least 7 wk postinfection. Unexpectedly, relatively mild EV-D68 infection also progressed to chronic lung disease in Foxj1-Scgb1a1-Cre-Stat1^f/f and Stat1 ^-/- mice but was limited (like viral replication) to airways. The results thereby provide proof-of-concept for a critical role of barrier epithelial cells in protection from acute illness and chronic disease after viral infection and suggest a specific role for airway epithelial cells given the limitation of EV-D68 replication and acute and chronic manifestations of disease primarily to airway tissue.

Prevalence and risk factors of chronic obstructive pulmonary disease in dairy farmers: AIRBAg study

BACKGROUND

The AIRBAg study was designed to assess the prevalence of chronic obstructive pulmonary disease (COPD) in dairy farmers and to define its associated risk factors.

METHODS

Between March 2012 and February 2017 randomly selected dairy farmers in the French region of Brittany were asked to complete a self-administered questionnaire and undergo an occupational health check-up with electronic mini-spirometry and standard spirometry. Those having one or more of the following features: chronic cough, chronic bronchitis, wheezing, dyspnea and/or a ratio FEV₁/FEV₆ < 80% were then referred to a pulmonologist for further check-up including spirometry with a reversibility test. Each COPD case was matched with three controls (dairy farmers and non-farm employees), for sex and age ( ± 5 years). Conditional multivariate logistic regression models were used to estimate the odds ratios between COPD occurrence and various risk factors.

RESULTS

The 1203 farmers examined included 525 (43.6%) who were "at risk of bronchial obstruction" and 432 (35.9%) of these saw the pulmonologist. This screening identified 16 (1.3%) cases of COPD, including eight non-smokers and five with an FEV₁ < 80% of predicted values. Their average age was 54.6 ( ± 7.7) years and 10 of them were men. None complained of illness before the study. Multivariate analyses revealed no significant occupational risk factors for COPD.

CONCLUSIONS

This unexpected result may be because Breton dairy farms began to modernize early (1950s), giving rise to conditions with much lower exposure to airborne contaminants.

Childhood asthma is associated with COPD and known asthma variants in COPDGene: a genome-wide association study

BACKGROUND

Childhood asthma is strongly influenced by genetics and is a risk factor for reduced lung function and chronic obstructive pulmonary disease (COPD) in adults. This study investigates self-reported childhood asthma in adult smokers from the COPDGene Study. We hypothesize that childhood asthma is associated with decreased lung function, increased risk for COPD, and that a genome-wide association study (GWAS) will show association with established asthma variants.

METHODS

We evaluated current and former smokers ages 45-80 of non-Hispanic white (NHW) or African American (AA) race. Childhood asthma was defined by self-report of asthma, diagnosed by a medical professional, with onset at < 16 years or during childhood. Subjects with a history of childhood asthma were compared to those who never had asthma based on lung function, development of COPD, and genetic variation. GWAS was performed in NHW and AA populations, and combined in meta-analysis. Two sets of established asthma SNPs from published literature were examined for association with childhood asthma.

RESULTS

Among 10,199 adult smokers, 730 (7%) reported childhood asthma and 7493 (73%) reported no history of asthma. Childhood asthmatics had reduced lung function and increased risk for COPD (OR 3.42, 95% CI 2.81-4.18). Genotype data was assessed for 8031 subjects. Among NHWs, 391(7%) had childhood asthma, and GWAS identified one genome-wide significant association in KIAA1958 (rs59289606, p = 4.82 × 10- 8). Among AAs, 339 (12%) had childhood asthma. No SNPs reached genome-wide significance in the AAs or in the meta-analysis combining NHW and AA subjects; however, potential regions of interest were identified. Established asthma SNPs were examined, seven from the NHGRI-EBI database and five with genome-wide significance in the largest pediatric asthma GWAS. Associations were found in the current childhood asthma GWAS with known asthma loci in IL1RL1, IL13, LINC01149, near GSDMB, and in the C11orf30-LRRC32 region (Bonferroni adjusted p < 0.05 for all comparisons).

CONCLUSIONS

Childhood asthmatics are at increased risk for COPD. Defining asthma by self-report is valid in populations at risk for COPD, identifying subjects with clinical and genetic characteristics known to associate with childhood asthma. This has potential to improve clinical understanding of asthma-COPD overlap (ACO) and enhance future research into ACO-specific treatment regimens.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00608764 (Active since January 28, 2008).

Epidemiology and risk factors of asthma-chronic obstructive pulmonary disease overlap in low- and middle-income countries

BACKGROUND

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) represents the confluence of bronchial airway hyperreactivity and chronic airflow limitation and has been described as leading to worse lung function and quality of life than found with either singular disease process.

OBJECTIVE

We aimed to describe the prevalence and risk factors for ACO among adults across 6 low- and middle-income countries (LMICs).

METHODS

We compiled cross-sectional data for 11,923 participants aged 35 to 92 years from 4 population-based studies in 12 settings. We defined COPD as postbronchodilator FEV₁/forced vital capacity ratio below the lower limit of normal, asthma as wheeze or medication use in 12 months or self-reported physician diagnosis, and ACO as having both.

RESULTS

The prevalence of ACO was 3.8% (0% in rural Puno, Peru, to 7.8% in Matlab, Bangladesh). The odds of having ACO were higher with household exposure to biomass fuel smoke (odds ratio [OR], 1.48; 95% CI, 0.98-2.23), smoking tobacco (OR, 1.28 per 10 pack-years; 95% CI, 1.22-1.34), and having primary or less education (OR, 1.35; 95% CI, 1.07-1.70) as compared to nonobstructed nonasthma individuals. ACO was associated with severe obstruction (FEV₁ %, <50; 31.6% of ACO vs 10.9% of COPD alone) and severe spirometric deficits compared with participants with asthma (-1.61 z scores FEV₁; 95% CI, -1.48 to -1.75) or COPD alone (-0.94 z scores; 95% CI, -0.78 to -1.10).

CONCLUSIONS

ACO may be as prevalent and more severe in LMICs than has been reported in high-income settings. Exposure to biomass fuel smoke may be an overlooked risk factor, and we favor diagnostic criteria for ACO that include environmental exposures common to LMICs.

Precision medicine in COPD: where are we and where do we need to go?

Chronic obstructive pulmonary disease (COPD) was the fourth leading cause of death worldwide in 2015. Current treatments for patients ease discomfort and help decrease disease progression; however, none improve lung function or change mortality. COPD is heterogeneous in its molecular and clinical presentation, making it difficult to understand disease aetiology and define robust therapeutic strategies. Given the complexity of the disease we propose a precision medicine approach to understanding and better treating COPD. It is possible that multiOMICs can be used as a tool to integrate data from multiple fields. Moreover, analysis of electronic medical records could aid in the treatment of patients and in the predictions of outcomes. The Precision Medicine Initiative created in 2015 has made precision medicine approaches to treat disease a reality; one of these diseases being COPD.

Determinants of incident asthma-COPD overlap: a prospective study of 55,110 middle-aged adults

Background and aim

Knowledge of the impact of social determinants driving asthma– chronic obstructive pulmonary disease overlap (ACO) is lacking. Our objective was to identify determinants of incident ACO.

Methods

A total of 55,053 adults (50–64 years) enrolled in the Danish Diet, Cancer, and Health cohort (1993–97) was followed in the National Patient Registry for admissions for asthma (DJ45–46) and chronic obstructive pulmonary disease (COPD; DJ40–44) and vital status. Incident ACO was defined as at least one hospital admission for both asthma and COPD (different time points, one after baseline). Detailed case history was obtained at baseline. Cox proportional hazards model was used to examine associations between possible determinants and incident ACO, in terms of hazard ratio (HR) and 95% confidence interval (CI).

Results

During follow-up, 561 incident cases of ACO were identified. Age (HR 4.4, 95% CI 3.3–5.9, age group 60–65 years), current smoking (HR 3.6, 95% CI 2.8–4.6), unemployment (HR 1.5, 95% CI 1.2–1.8), and being divorced (HR 1.5, 95% CI 1.2–1.9) determined a higher risk of incident ACO, whereas the opposite was found for leisure-time physical activity (HR 0.7, 95% CI 0.6–0.8) and high educational level (HR 0.7, 95% CI 0.5–0.9). In contrast to ACO, preexisting myocardial infarction (MI; HR 1.5, 95% CI 1.2–1.8) and stroke (HR 1.5, 95% CI 1.2–1.9) were associated with a higher risk of COPD.

Conclusion

Incident ACO is to a large extent determined by factors related to lifestyle and socioeconomic status.

Health characteristics of patients with asthma, COPD and asthma-COPD overlap in the NHANES database

Introduction

Asthma and COPD have overlapping characteristics. As there are limited data on whether asthma–COPD overlap (ACO) represents a distinct condition, this study aimed to determine the similarities and differences of ACO with asthma and COPD.

Methods

US population-based, cross-sectional study using National Health and Nutrition Examination Survey data (2009–2012) compared participants with ACO vs those with asthma or COPD, each as mutually exclusive disease states. Demographics, health status, disability/limitations, health care resource utilization, clinical characteristics, and peripheral blood eosinophil counts were analyzed.

Results

A total of 1,609, 479, and 299 participants with asthma, COPD, and ACO, respectively, were included. An age-matched asthma subgroup included 299 participants from the asthma group. Compared with asthma and COPD, participants with ACO had worse health status, increased disease burden, and more comorbid conditions. The ACO, vs age-matched asthma subgroup, had lower percent predicted prebronchodilator forced expiratory volume in 1 second (82.1% vs 88.0%; P=0.017). The ACO group had significantly more asthma attacks in the past year than the age-matched asthma subgroup (49.8% vs 38.4%; P<0.001). The ACO group had more participants with postbronchodilator forced expiratory volume in 1 second <80% predicted (52.1%) vs COPD (30.8%; P=0.003) and more participants with blood eosinophil counts ≥400 cells/µL (16.9%) vs COPD (9.5%; P=0.007) and the asthma subgroup (6.7%; P=0.014).

Conclusion

The ACO group represents an important subset of patients with chronic respiratory disease with an increased burden of disease over asthma and COPD individually. Early identification of this population will enable appropriate therapeutic interventions in a timely manner.

COPD uncovered: a cross-sectional study to assess the socioeconomic burden of COPD in Japan

Background

COPD remains a major health problem in Japan. Patients with COPD experience a reduced quality of life (QoL) and have a higher chance of work impairment and productivity loss. However, there is a lack of data on the impact of COPD in terms of QoL and work activity impairment in Japan. This study assessed the socioeconomic burden of COPD in Japan and the impact it may have on the working age population.

Patients and methods

This was a 2-year retrospective chart review in COPD patients aged ≥40 years, with at least one health care visit to clinic or hospital in the previous 12 months. Patients were required to have available medical charts for at least the previous 24 months. Symptoms were assessed using COPD assessment test score; EuroQoL Group 5 Dimension (EQ-5D-5L) and work productivity and activity impairment general health questionnaires were used to evaluate health-related QoL and work productivity, and health care resource utilization data were obtained from clinical charts.

Results

In total, 71 patients aged <65 years, and 151 patients aged ≥65 years were included; the majority of patients had moderate or severe airflow limitation. Exacerbations (moderate or severe) were reported by ~35% of patients in both age groups; 52.1% and 62.9% of patients in the <65-year and ≥65-year age groups had COPD assessment test scores ≥10. EQ-5D-5L index scores in the <65-year and ≥65-year age groups were 0.79 and 0.77, respectively. Work productivity and activity impairment scores were higher in <65-year age group. Annual costs of health care resource use per patient in the <65-year and ≥65-year age groups were ¥438,975 (US$4,389) and ¥467,871 (US$4,678), respectively. Costs due to productivity loss were estimated to be ¥5,287,024 (US$52,870) in the <65-year age group and ¥3,018,974 (US$30,187) in the ≥65-year age group.

Conclusion

COPD represents a significant socioeconomic burden in Japan. Patients with COPD report significant use of health care resources. Higher impact on work impairment and productivity loss was observed frequently in the working age population.

A Review of Portable Electronic Spirometers: Implications for Asthma Self-Management

PURPOSE OF REVIEW

Although portable electronic spirometers allow for at-home lung function monitoring, a comprehensive review of these devices has not yet been conducted. We conducted a systematic search and review of commercially available portable electronic spirometers designed for asthma patient use.

RECENT FINDINGS

All devices (N = 16) allowed for monitoring of basic lung function parameters, but only 31% provided in-app videos on how to perform breathing maneuvers. Most devices (63%) provided graphical representations of lung function results, but only 44% gave immediate feedback on the quality of the breathing maneuver. Several devices (25%) were FDA-approved and cost ranged from US$99 to $1390. Information on data security (63%), measurement accuracy (50%), and association with patient outcomes (0%) was commonly limited. This review found that providers' ability to make informed decisions about whether asthma patients may benefit from portable electronic spirometers is limited due to lack of patient outcome data.

Treatable traits of chronic airways disease

PURPOSE OF REVIEW

To describe the rationale on which the treatable traits approach to the management of airways disease is based and the issues that need to be considered for its implementation in clinical practice.

RECENT FINDINGS

In clinical practice, treatable traits can be classified according to both endotypes and phenotypes, broadly grouped within pulmonary, extrapulmonary, environmental and behavioural factors. Specific investigations and treatments are undertaken for each of the traits rather than a 'one size fits all' stepwise approach to pharmacological treatment which currently represents the core of asthma and chronic obstructive pulmonary disease (COPD) guidelines. Although there is strong evidence of the benefit of the treatable traits approach to specific traits in asthma and/or COPD, there is uncertainty regarding the preferred method of implementation, efficacy and cost-effectiveness of multidimensional intervention programmes in clinical practice. It is likely that 'master protocols' for randomized controlled trials will be required to evaluate such multiple interventions in broad populations of patients with airways disease.

SUMMARY

Current evidence suggests that the precision medicine approach based on the identification and treatment of treatable traits is preferable to a 'one-size-fits-all' stepwise approach to the treatment of airways disease, although high-quality evidence to guide the practical application of this multidimensional management strategy is now required. VIDEO ABSTRACT.

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.

Combined Assessment of Serum Periostin and YKL-40 May Identify Asthma-COPD Overlap

BACKGROUND

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) has been proposed as a different diagnosis from asthma and COPD. However, little is known about the role of serum biomarkers in ACO.

OBJECTIVE

To evaluate serum periostin, a type 2 biomarker, and serum chitinase-3-like protein 1 (YKL-40), a useful biomarker for COPD, in Japanese patients with asthma, ACO, or COPD, and investigate the role of these biomarkers in identifying ACO.

METHODS

Subjects included Japanese patients with asthma (n = 177), ACO (n = 115), or COPD (n = 61). Serum periostin, YKL-40, and total IgE, blood eosinophils, and fractional exhaled nitric oxide were measured and compared among the patients.

RESULTS

Serum periostin was high in both asthma and ACO, but not in COPD, whereas serum YKL-40 was high in both COPD and ACO, but not in asthma. Serum periostin levels correlated weakly with eosinophil counts in asthma, ACO, and COPD. Multivariate linear regression analysis revealed that older age, lower body mass index, higher eosinophil counts, higher total IgE, and the absence of the diagnosis of COPD were significantly associated with higher periostin levels. Based on cutoff values derived by receiver operating characteristic analysis (periostin: 55.1 ng/mL; YKL-40: 61.3 ng/mL), patients were classified into high or low groups. The proportion of patients with both high serum periostin and YKL-40 levels was significantly higher in ACO than in asthma or COPD.

CONCLUSIONS

Serum periostin levels were comparable between asthma and ACO, whereas YKL-40 was comparable between ACO and COPD. Combined assessment of serum periostin and YKL-40 may identify ACO.

Chronic obstructive pulmonary disease subpopulations and phenotyping

The diagnosis and treatment of chronic obstructive pulmonary disease (COPD) has been based largely on a one-size-fits-all approach. Diagnosis of COPD is based on meeting the physiologic criteria of fixed obstruction in forced expiratory flows and treatment focus on symptomatic relief, with limited effect on overall prognosis. However, patients with COPD have distinct features that determine very different evolutions of the disease. In this review we highlight distinct subgroups of COPD characterized by unique pathophysiologic derangements, response to treatment, and disease progression. It is likely that identification of subgroups of COPD will lead to discovery of much needed disease-modifying therapeutic approaches. We argue that a precision approach that integrates multiple dimensions (clinical, physiologic, imaging, and endotyping) is needed to move the field forward in the treatment of this disease.

Blood eosinophil count thresholds and exacerbations in patients with chronic obstructive pulmonary disease

BACKGROUND

Eosinophilic airway inflammation in patients with chronic obstructive pulmonary disease (COPD) is associated with exacerbations and responsivity to steroids, suggesting potential shared mechanisms with eosinophilic asthma. However, there is no consistent blood eosinophil count that has been used to define the increased exacerbation risk.

OBJECTIVE

We sought to investigate blood eosinophil counts associated with exacerbation risk in patients with COPD.

METHODS

Blood eosinophil counts and exacerbation risk were analyzed in patients with moderate-to-severe COPD by using 2 independent studies of former and current smokers with longitudinal data. The Genetic Epidemiology of COPD (COPDGene) study was analyzed for discovery (n = 1,553), and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study was analyzed for validation (n = 1,895). A subset of the ECLIPSE study subjects were used to assess the stability of blood eosinophil counts over time.

RESULTS

COPD exacerbation risk increased with higher eosinophil counts. An eosinophil count threshold of 300 cells/μL or greater showed adjusted incidence rate ratios for exacerbations of 1.32 in the COPDGene study (95% CI, 1.10-1.63). The cutoff of 300 cells/μL or greater was validated for prospective risk of exacerbation in the ECLIPSE study, with adjusted incidence rate ratios of 1.22 (95% CI, 1.06-1.41) using 3-year follow-up data. Stratified analysis confirmed that the increased exacerbation risk associated with an eosinophil count of 300 cells/μL or greater was driven by subjects with a history of frequent exacerbations in both the COPDGene and ECLIPSE studies.

CONCLUSIONS

Patients with moderate-to-severe COPD and blood eosinophil counts of 300 cells/μL or greater had an increased risk exacerbations in the COPDGene study, which was prospectively validated in the ECLIPSE study.

Asthma Over the Age of 65: All's Well That Ends Well

Asthma in older adults (often classified as those 65 years or older) is relatively common, underdiagnosed, and suboptimally treated. It is an important health problem, as the population of the United States continues to age. Unfortunately, asthma morbidity and mortality rates are highest in this age group. Alterations in the innate and adaptive immune responses occur with aging, and contribute to pathophysiologic differences and subsequent treatment challenges. The symptoms of asthma may differ from those in younger populations, and often include fatigue. There are unique factors that can complicate asthma management among older adults, including comorbidities, menopause, caregiver roles, and depression. Pharmacologic therapies are often not as effective as in younger populations, and may have greater side effects. Spirometry, peak flow measurements, and asthma education are typically underused, and may contribute to delays in diagnosis as well as worse outcomes. There are specific strategies that health care providers can take to improve the care of older adults with asthma.

Of pleiotropy and trajectories: Does the TGF-β pathway link childhood asthma and chronic obstructive pulmonary disease?

The study of developmental trajectories is where epigenetics truly shines. The "epi" in epigenetics captures the fact that although epigenetic processes also preside over the maintenance and termination of gene expression, the unfolding and remodeling of chromatin architecture are especially critical to prepare genes for regulated transcription. These properties imply being on a path, a trajectory to events that will occur later thanks to epigenetic programming. Thus epigenetics is about timed and timely events. In this article we discuss epigenetic and genetic evidence from several independent studies of asthma, chronic obstructive pulmonary disease, and lung function, which converge to highlight a potential role of the TGF-β gene pathway in these processes. These results raise the possibility that at least in a subset of subjects, these conditions might be functionally connected in ways that need to be further defined but that likely reflect the uniquely pleiotropic nature of TGF-β pathway genes, particularly their ability to control both lung development and immune responses essential for regulation and inflammation. Further characterization of this pathway in longitudinally phenotyped populations might unmask novel trajectories to lung disease that begin in utero and unfold into old age.

Plasma YKL-40 and NGAL are useful in distinguishing ACO from asthma and COPD

BACKGROUND

Asthma-chronic obstructive pulmonary disorder (COPD) overlap (ACO) is characterized by the coexistence of features of both asthma and COPD and is associated with rapid progress and a poor prognosis. Thus, the early recognition of ACO is crucial.

OBJECTIVES

We sought to explore the plasma levels of biomarkers associated with asthma (periostin, TSLP and YKL-40), COPD (NGAL) and their possible correlation with lung function, the bronchodilator response and radiographic imaging in patients with asthma, COPD and with features of ACO.

METHODS

We enrolled 423 subjects from 6 clinical centers. All participants underwent blood collection, lung function measurements, bronchodilator response tests and high-resolution CT. Correlations of the plasma biomarkers with lung function, the bronchodilator response and percentemphysema were calculated by Spearman's rank correlation and multivariate stepwise regressionanalysis.

RESULTS

1) Patients with features of ACO had lower plasma YKL-40 than COPD patients and a moderate elevated plasma level of NGAL compared with asthma patients. 2) Patients with features of ACO had an intermediate degree of airflow obstruction, the bronchodilator response and emphysema between patients with COPD and asthma. 3) Plasma YKL-40 was negatively correlated with lung function and with the bronchodilator response, and plasma NGAL was positively correlated with the extent of emphysema.

CONCLUSIONS

Plasma YKL-40 is a promising candidate for distinguishing between patients with features of ACO and COPD patients, while plasma NGAL may be a valuable biomarker for differentiating between patients with features of ACO and asthma patients.

CLINICAL TRIAL REGISTRATION

ChiCTR-OOC-16009221.