Improved criterion for assessing lung function reversibility

129Xe-MRI ventilation and acinar abnormalities highlight the significance of spirometric dysanapsis: findings from the NOVELTY ADPro UK substudy

RATIONALE

Airways dysanapsis is defined by CT or spirometry as a mismatch between the size of the airways and lung volume and is associated with increased risk of developing chronic obstructive pulmonary disease (COPD). Lung disease in participants with dysanapsis and a label of asthma and/or COPD remains poorly understood.

METHODS

In participants with asthma and/or COPD, we used 129Xe-MRI to assess ventilation, acinar dimensions and gas exchange, and pulmonary function tests, and compared people with spirometric dysanapsis (forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<-1.64 z and FEV1>-1.64 z) to those with normal spirometry (FEV1, FVC and FEV1/FVC>-1.64 z).

RESULTS

From 165 participants assessed in the NOVELTY (NOVEL observational longiTudinal studY) ADPro (advanced diagnostic profiling) study with a physician-assigned diagnosis of asthma and/or COPD, 43 had spirometric dysanapsis and were age-matched to 43 participants with normal spirometry. Participants with dysanapsis had significantly increased ventilation defects (median difference (md) (95% CI) = 4.0% (1.42% to 5.38%), p<0.001), ventilation heterogeneity (md (95% CI) = 2.56% (1.31% to 3.56%), p<0.001) and measures of acinar dimensions (md (95% CI) = 0.004 cm2.s-1 (0.0009 to 0.007), p=0.009) from 129Xe-MRI, than those with normal spirometry. At the 1-year follow-up, only participants with dysanapsis had a significant increase in ventilation defects (md (95% CI)=0.45% (0.09% to 2.1%),p=0.016). Lower FEV1/FVC in the dysanapsis cohort was associated with increased ventilation defects (r=-0.64, R2=0.41, p<0.001) and increased acinar dimensions (r=-0.52, R2=0.38, p<0.001), with the highest values seen in those with an FVC above the upper limit of normal.

CONCLUSIONS

Participants with asthma and/or COPD, presenting to primary care with spirometric dysanapsis, exhibited increased lung abnormalities on 129Xe-MRI, when compared with those with normal spirometry. Spirometric dysanapsis in asthma and/or COPD is therefore associated with significant lung disease, and the FEV1/FVC is related to the degree of airways abnormality on 129Xe-MRI.

Regional brain structural alterations in reward and salience networks in asthma

INTRODUCTION

Chronic systemic inflammation is highly prevalent and has deleterious effects on the brain, impacting both function and structure, and manifesting in elevations in psychological symptoms transdiagnostically. Asthma is a chronic inflammatory disease of the airway that affects more than 300 million people worldwide and is known to be highly comorbid with psychological and cognitive dysfunction. Though a growing corpus of work has identified functional brain abnormalities associated with asthma, limited research has investigated structural differences which may partially underlie functional changes. Identifying and characterizing asthma-related structural brain changes will shed light on the neurobiology through which asthma impacts mental function and has the potential to inform prophylaxis and treatment.

METHODS

We examined differences in regional brain volume, cortical thickness, and surface area, in 128 individuals with asthma compared to 134 non-asthma healthy controls. Five regions of interest were examined a priori, based on their previous implication in inflammation-related functional consequences (dorsal and ventral striatum, pallidum, and insula), or previous evidence of asthma-related structural impact (hippocampus and thalamus). We supplemented our region of interest approach with a voxel-wise whole-brain analysis. Additionally, we examined the association of brain structure with depression symptoms, asthma severity, degree of inflammation, and plasma biomarkers of neuroinflammation, neurodegeneration, and Alzheimer's disease specific pathology.

RESULTS

Compared to non-asthma control participants, those with asthma had smaller nucleus accumbens volumes, thicker orbitofrontal cortices, larger middle frontal cortex surface areas, and greater diencephalon volumes. Those with more severe asthma had smaller nucleus accumbens and dorsal striatal volumes, reduced anterior cingulate cortex surface area, and greater amygdala volume compared to those with mild asthma. In untreated asthma patients, greater depressive symptoms were associated with smaller striatal volume, suggesting a potential CNS-protective effect of medications that reduce airway inflammation in asthma. In addition, a plasma marker of astrogliosis was associated with larger diencephalon, cerebellum, brainstem, and thalamus volumes, but reduced insula thickness and surface area.

CONCLUSIONS

Patterns of structural brain changes in participants with asthma encompass key regions of reward and salience networks, which may in part give rise to the functional alterations in these networks characteristic of chronic systemic inflammation.

Bronchodilator responsiveness in chronic obstructive pulmonary disease: prevalence, significance, and clinical implications

PURPOSE OF REVIEW

Bronchodilator responsiveness (BDR) is often considered a key feature distinguishing asthma from chronic obstructive pulmonary disease (COPD). However, recent evidence suggests that BDR alone may not be a reliable discriminator between these conditions. There is still no consensus on BDR definitions and testing protocols. Additionally, it remains unclear whether BDR is linked to a specific COPD phenotype or influences treatment responses. Our review of recent literature attempts to clarify some of these issues.

RECENT FINDINGS

A significant proportion of COPD patients demonstrate BDR, but the variability in testing procedures and definitions makes it challenging to draw any definite conclusion. There is no evident association between BDR and specific COPD characteristics. A few studies suggest that BDR may be associated with marginally better treatment response and disease outcomes in COPD. The impact of recent changes in BDR definitions on clinical practice remains to be fully understood.

SUMMARY

There is still no clear, clinically relevant threshold to define BDR. BDR is an unreliable discriminator to differentiate asthma from COPD and is not consistently linked to any specific COPD phenotype, treatment response, or disease outcomes. Further research is needed to refine the definitions and implications of BDR in COPD.

New spirometry recommendations from the Brazilian Thoracic Association - 2024 update

The latest pulmonary function guideline from the Brazilian Thoracic Association was published in 2002, since which there have been updates to international guidelines (mainly those from the European Respiratory Society and the American Thoracic Society), as well as new national and international publications on various aspects of the performance, interpretation, and clinical implications of spirometry. Despite those updates, a careful analysis of what applies to the reality in Brazil is essential, because there have been studies that evaluated individuals who are representative of our population and who could show responses different from those of individuals in other regions of the world. This document is the result of the work of a group of specialists in pulmonary function who evaluated relevant scientific articles that could be applicable to the population of Brazil. After the discussions, new spirometry guidelines were drawn up, covering various aspects such as its technical parameters and performance; its indications and contraindications; its interpretation; concepts of normality and their related variability; reference values; classification of functional severity; and response to an inhaled bronchodilator. Finally, the guidelines emphasize the need to always interpret spirometry results in the context of the clinical condition of the patient and of the pretest probability.

ERS/ATS Global Lung Function Initiative normal values and classifying severity based on z-scores instead of per cent predicted

Among the most discussed issues in the field of pulmonary function testing are reference equations and standardised methods of interpreting pulmonary function test (PFT) results. The Global Lung Function Initiative (GLI) task force gathered information from multiple countries with diverse ethnicities to create a multi-ethnic reference formula suitable for a broad age range. Their first output was the GLI-2012 spirometry reference equations. Together with the GLI-2012 reference equations, the GLI document recommended the use of z-scores to standardise the interpretation of PFT results. Z-scores were introduced as an alternative to per cent predicted and fixed thresholds in interpreting PFTs. After more than a decade, there is still debate on which method of interpretation is better.

Assessing the Impact of the Updated 2021 European Respiratory Society/American Thoracic Society Criteria on Bronchodilator Responsiveness in Asthma

Introduction The European Respiratory Society/American Thoracic Society (ERS/ATS) Task Force released new technical standards on spirometry interpretation in 2021. Our study compares bronchodilator responsiveness (BDR) in asthma, evaluating the impact of the 2005 and 2021 ERS/ATS criteria and the influence of predictive equations. Methods A retrospective cohort study of adult patients with asthma was referred to spirometry with a BDR test at the Institute for Pulmonary Diseases of Vojvodina, Sremska Kamenica, Serbia. The study included adult patients with asthma who underwent BDR testing in the Department of Respiratory Pathophysiology at the institute and had available data on height, gender, age, race, and eosinophil count. Results Among 197 patients, 69 were men (35.0%), the median age was 47 years (interquartile range (IQR) 38-60), and a positive BDR test occurred in 50 (25.38%) according to the 2005 criteria and 42 (21.32%) according to 2021 criteria when using the Global Lung Initiative (GLI) reference equations. Strong agreement was observed between the ERS/ATS 2005 and 2021 criteria (Cohen's kappa index: 0.887, 95%, CI 0.810 to 0.963). Similar results were found with the Third National Health and Nutrition Examination Survey (NHANES III) and the European Community of Coal and Steel (ECCS) predictive equations. Positive BDR tests were common in patients with moderately severe and severe forced expiratory volume in one second (FEV1) impairment and were not associated with eosinophil count or total serum immunoglobulin E (IgE) levels. Conclusion The introduction of the 2021 ERS/ATS criteria did not significantly alter the classification of BDR in the majority of asthma patients, ensuring diagnostic stability. Whichever criterion was used, positive BDR correlated with the extent of FEV1 impairment, but not asthma biomarkers.

[Asthma]

Asthma is a chronic inflammatory disease that affects about 5% of the world's population and generates high health and social costs. Proper management of the disease requires a correct diagnosis, based on objective measures of functional impairment, as well as symptom control and assessment of the future risk of exacerbations.It has been estimated that 18% of asthma patients in Western Europe have severe asthma and approximately 50% of them have poor control. The severity of asthma is established based on the minimum maintenance treatment needs to achieve control. Asthma clinical practice guidelines recommend classifying severe patients into allergic asthma (T2); eosinophilic asthma (T2) and non-T2 asthma in order to establish the most appropriate treatment.In recent decades, new biological therapies have been developed that can be applied according to the phenotype and endotype of asthma, allowing for selective and personalized treatment. These phenotypes and endotypes can change over time and therefore, the identification of biomarkers capable of predicting the severity, the course of the disease and the response to a given treatment seems essential. A large number of biomarkers have been studied in asthma, but so far only a few can be readily used in routine clinical practice. The application of omics technologies (epigenomics, genomics, transcriptomics, proteomics, metabolomics, lipidomics, etc.) for this purpose is still in the research phase.

Prevalence, Diagnostic Utility and Associated Characteristics of Bronchodilator Responsiveness

Rationale: The prevalence and diagnostic utility of bronchodilator responsiveness (BDR) in a real-life setting is unclear. Objective: To explore this uncertainty in patients aged ⩾12 years with physician-assigned diagnoses of asthma, asthma and chronic obstructive pulmonary disease (COPD), or COPD in NOVELTY, a prospective cohort study in primary and secondary care in 18 countries. Methods: The proportion of patients with a positive BDR test in each diagnostic category was calculated using 2005 (ΔFEV1 or ΔFVC ⩾12% and ⩾200 ml) and 2021 (ΔFEV1 or ΔFVC >10% predicted) European Respiratory Society/American Thoracic Society criteria. Measurements and Main Results: We studied 3,519 patients with a physician-assigned diagnosis of asthma, 833 with a diagnosis of asthma + COPD, and 2,436 with a diagnosis of COPD. The prevalence of BDR was 19.7% (asthma), 29.6% (asthma + COPD), and 24.7% (COPD) using 2005 criteria and 18.1%, 23.3%, and 18.0%, respectively, using 2021 criteria. Using 2021 criteria in patients diagnosed with asthma, BDR was associated with higher fractional exhaled nitric oxide; lower lung function; higher symptom burden; more frequent hospital admissions; and greater use of triple therapy, oral corticosteroids, or biologics. In patients diagnosed with COPD, BDR (2021) was associated with lower lung function and higher symptom burden. Conclusions: BDR prevalence in patients with chronic airway diseases receiving treatment ranges from 18% to 30%, being modestly lower with the 2021 than with the 2005 European Respiratory Society/American Thoracic Society criteria, and it is associated with lower lung function and greater symptom burden. These observations question the validity of BDR as a key diagnostic tool for asthma managed in clinical practice or as a standard inclusion criterion for clinical trials of asthma and instead suggest that BDR be considered a treatable trait for chronic airway disease.

Routine pulmonary lung function tests: Interpretative strategies and challenges

Introduction: The diagnosis and management of common chronic respiratory diseases depend on various parameters obtained from pulmonary function tests (PFTs), such as spirometry, plethysmography, and carbon monoxide diffusion capacity (DLCO). These tests are interpreted following guidelines established by reputable scientific societies like the European Respiratory Society and the American Thoracic Society (ERS/ATS). Aim and Methods: This review aimed to offer a comprehensive framework for interpreting PFTs, incorporating the latest ERS/ATS update (i.e.; 2022), and to briefly explore some complex cases to shed light on their implications for understanding PFTs. Results: The ERS/ATS update outlines a systematic approach to interpreting PFT results, which involves several steps. Initially, results are compared to those of a healthy reference population to determine normal, low, or high parameters. Then, potential ventilatory impairments (VIs), such as obstructive or restrictive VIs, are identified, which could indicate specific chronic respiratory or extra-respiratory diseases. The severity of identified VIs or reductions in DLCO is then assessed. If bronchodilator testing is performed, its response is evaluated. Lastly, any significant changes in PFT parameters over time are noted by comparing current results with previous ones, if available. Despite the clarity provided by the ERS/ATS update, certain uncertainties persist and require clarification, such as the identification of new patterns (e.g.; non-obstructive abnormal spirometry, isolated low forced expiratory volume in 1 s), and classifications of mixed VI or lung hyperinflation in terms of functional severity. Conclusion: This review is a comprehensive framework for interpreting PFTs. Since some issues pose uncertainty in clinical practice, it would be beneficial to the ERS/ATS to reconcile some inconsistencies and provide clearer guidance on different classifications and VIs.

Bronchodilator response does not associate with asthma control or symptom burden among patients with poorly controlled asthma

PURPOSE

The purpose of this study was to determine how four different definitions of bronchodilator response (BDR) relate to asthma control and asthma symptom burden in a large population of participants with poorly controlled asthma.

PROCEDURES

We examined the baseline change in FEV1 and FVC in response to albuterol among 931 participants with poorly controlled asthma pooled from three clinical trials conducted by the American Lung Association - Airways Clinical Research Centers. We defined BDR based on four definitions and analyzed the association of each with asthma control as measured by the Asthma Control Test or Asthma Control Questionnaire, and asthma symptom burden as measured by the Asthma Symptom Utility Index.

MAIN FINDINGS

A BDR was seen in 31-42% of all participants, depending on the definition used. There was good agreement among responses (kappa coefficient 0.73 to 0.87), but only 56% of participants met all four definitions for BDR. A BDR was more common in men than women, in Blacks compared to Whites, in non-smokers compared to smokers, and in non-obese compared to obese participants. Among those with poorly controlled asthma, 35% had a BDR compared to 25% of those with well controlled asthma, and among those with a high symptom burden, 34% had a BDR compared to 28% of those with a low symptom burden. After adjusting for age, sex, height, race, obesity and baseline lung function, none of the four definitions was associated with asthma control or symptom burden.

CONCLUSION

A BDR is not associated with asthma control or symptoms in people with poorly controlled asthma, regardless of the definition of BDR used. These findings question the clinical utility of a BDR in assessing asthma control and symptoms.

Clinical Manifestations of Subjects With the Non-Specific Pulmonary Function Test Pattern

Introduction

Non-specific pattern (NSP) is a subgroup of preserved ratio impaired spirometry (PRISm) that requires a normal total lung capacity measurement. NSP has been historically classified as being an obstructive lung disease pattern. There has been heightened interest and investigation into PRISm recently as it has been associated with an increased likelihood of developing chronic obstructive pulmonary disease (COPD). Given the inherent challenges of understanding the clinical significance of the NSP, the aim of this study was to further explore the clinical characteristics of patients with this pulmonary function test pattern.

Material and methods

We identified 111 and 79 subjects using pre-bronchodilator (pre-BD) and post-bronchodilator (post-BD) values, respectively, that met criteria for NSP. The outpatient medical records were retrospectively reviewed for associated diagnoses that were then clustered into 'obstructive' or 'non-obstructive' groups based on the treating physician's primary pulmonary clinical diagnosis.

Results

Within this NSP cohort, cough, wheezing and sputum production were documented more frequently in those with an obstructive lung disease diagnosis. Whether identified using pre-BD or post-BD spirometric values, those with NSP and a positive BD response were more likely to carry an obstructive lung disease diagnosis.

Conclusion

Approximately one third of patients with NSP in this study were not given an obstructive lung disease diagnosis by their clinician, which supports the classification of NSP as not an exclusively obstructive lung disease pattern. However, the presence of supporting clinical symptoms, such as cough with sputum production and wheeze, and/or a positive BD response on PFT, support a diagnosis of obstruction in patients with NSP.

Determinants of lung function across childhood in the Severe Asthma Research Program (SARP) 3

BACKGROUND

Children with asthma are at risk for low lung function extending into adulthood, but understanding of clinical predictors is incomplete.

OBJECTIVE

We sought to determine phenotypic factors associated with FEV1 throughout childhood in the Severe Asthma Research Program 3 pediatric cohort.

METHODS

Lung function was measured at baseline and annually. Multivariate linear mixed-effects models were constructed to assess the effect of baseline and time-varying predictors of prebronchodilator FEV1 at each assessment for up to 6 years. All models were adjusted for age, predicted FEV1 by Global Lung Function Initiative reference equations, race, sex, and height. Secondary outcomes included postbronchodilator FEV1 and prebronchodilator FEV1/forced vital capacity.

RESULTS

A total of 862 spirometry assessments were performed for 188 participants. Factors associated with FEV1 include baseline Feno (B, -49 mL/log2 PPB; 95% CI, -92 to -6), response to a characterizing dose of triamcinolone acetonide (B, -8.4 mL/1% change FEV1 posttriamcinolone; 95% CI, -12.3 to -4.5), and maximal bronchodilator reversibility (B, -27 mL/1% change postbronchodilator FEV1; 95% CI, -37 to -16). Annually assessed time-varying factors of age, obesity, and exacerbation frequency predicted FEV1 over time. Notably, there was a significant age and sex interaction. Among girls, there was no exacerbation effect. For boys, however, moderate (1-2) exacerbation frequency in the previous 12 months was associated with -20 mL (95% CI, -39 to -2) FEV1 at each successive year. High exacerbation frequency (≥3) 12 to 24 months before assessment was associated with -34 mL (95% CI, -61 to -7) FEV1 at each successive year.

CONCLUSIONS

In children with severe and nonsevere asthma, several clinically relevant factors predict FEV1 over time. Boys with recurrent exacerbations are at high risk of lower FEV1 through childhood.

Bronchodilator Responsiveness Defined by the 2005 and 2021 ERS/ATS Criteria in Patients with Asthma as Well as Chronic Obstructive Pulmonary Disease

Background

In the 2021 ERS/ATS interpretive strategies for routine lung function tests, a positive bronchodilator response (BDR) was updated as a change of >10% relative to the predicted value in forced expiratory volume in 1 second (FEV₁) or forced vital capacity (FVC). We aimed to explore the differences between the 2005 and 2021 ERS/ATS criteria applied to patients with asthma as well as chronic obstructive pulmonary disease (COPD).

Methods

BDR test data about asthma patients aged 6–80 years and COPD patients aged 18–80 years were derived from the National Respiratory Medicine Center, First Affiliated Hospital of Guangzhou Medical University, from January 2017 to March 2022. BDR results defined by the 2005 and 2021 ERS/ATS criteria were named 2005-BDR and 2021-BDR, respectively. We compared differences between 2005-BDR and 2021-BDR and analyzed the trend in the proportion of positive BDR (BDR+) with the level of airflow obstruction.

Results

A total of 4457 patients with asthma and 7764 patients with COPD were included in the analysis. The percentages of 2005-BDR+ and 2021-BDR+ were 63.32% and 52.84% for asthma, 30.92% and 22.94% for COPD, respectively. Of patients with 2005-BDR+, 81.86% for asthma and 70.18% for COPD showed 2021-BDR+ results, and these patients had higher FEV₁%pred, FVC%pred (all P<0.05). Whichever BDR criterion was adopted, the proportion of BDR+ had an upward linear trend with the increased degree of airflow obstruction in COPD, but exhibited an approximate inverted U-shaped curve in asthma. In COPD, the proportion of BDR_FEV1 was negatively associated with the degree of airflow obstruction, while BDR_FVC was positively associated (all P<0.05).

Conclusion

Compared with 2005-BDR+, the proportion of 2021-BDR+ reduced markedly in patients with asthma and COPD, but their trends with the degree of airflow obstruction did not change. Patients with consistent BDR+ had higher initial FEV₁%pred and FVC%pred.

ERS/ATS technical standard on interpretive strategies for routine lung function tests

BACKGROUND

Appropriate interpretation of pulmonary function tests (PFTs) involves the classification of observed values as within/outside the normal range based on a reference population of healthy individuals, integrating knowledge of physiological determinants of test results into functional classifications and integrating patterns with other clinical data to estimate prognosis. In 2005, the American Thoracic Society (ATS) and European Respiratory Society (ERS) jointly adopted technical standards for the interpretation of PFTs. We aimed to update the 2005 recommendations and incorporate evidence from recent literature to establish new standards for PFT interpretation.

METHODS

This technical standards document was developed by an international joint Task Force, appointed by the ERS/ATS with multidisciplinary expertise in conducting and interpreting PFTs and developing international standards. A comprehensive literature review was conducted and published evidence was reviewed.

RESULTS

Recommendations for the choice of reference equations and limits of normal of the healthy population to identify individuals with unusually low or high results are discussed. Interpretation strategies for bronchodilator responsiveness testing, limits of natural changes over time and severity are also updated. Interpretation of measurements made by spirometry, lung volumes and gas transfer are described as they relate to underlying pathophysiology with updated classification protocols of common impairments.

CONCLUSIONS

Interpretation of PFTs must be complemented with clinical expertise and consideration of the inherent biological variability of the test and the uncertainty of the test result to ensure appropriate interpretation of an individual's lung function measurements.

Reduced bronchodilator reversibility correlates with non-type 2 high asthma and future exacerbations: A prospective cohort study

BACKGROUND

Given that airway obstruction in asthma is not always fully reversible, reduced bronchodilator reversibility (BDR) may be a special asthma phenotype.

OBJECTIVE

To explore the characteristics of BDR^high/low phenotypes (defined using two BDR criteria) and their associations with asthma exacerbations (AEs).

METHODS

After baseline assessments, all patients were classified into BDR^high or BDR^low phenotypes. This study consisted of 2 parts. Part I was a 12-month prospective observational cohort study designed to identify the clinical characteristics and associations with future AEs in BDR^high/low phenotypes (n = 456). Part II, designed as a post hoc analysis of the data obtained in Part I, was conducted to assess the association between BDR^high/low phenotypes and treatment responsiveness (n = 360).

RESULTS

Subjects with BDR^low phenotypes had better baseline asthma symptom control and was negatively associated with eosinophilic asthma and type 2 (T2) high asthma. During the 12-month follow-up, those with BDR^low phenotypes had a higher risk of severe AEs (SAEs) (guideline-based criterion: RR_adj = 2.24, 95% CI = [1.25, 3.68]; Ward's criterion: RR_adj = 2.46, 95% CI = [1.40, 4.00]) and moderate-to-severe AEs (MSAEs) (guideline-based criterion: RR_adj = 1.83, 95% CI = [1.22, 2.56]; Ward's criterion: RR_adj = 1.94, 95% CI = [1.32, 2.68]) in the following year according to logistic regression models. Similar findings were obtained with negative binominal regression models. BDR^low phenotype was a risk factor for an insensitive response to anti-asthma treatment (guideline-based criterion: OR_adj = 1.96, 95% CI = [1.05, 3.65]; Ward's criterion: OR_adj = 2.01, 95% CI = [1.12, 3.58]).

CONCLUSION

We identified that BDR^low phenotype was associated with non-T2 high asthma and future AEs. These findings have clinically relevant implications for asthma management.

Clinical value of bronchodilator response for diagnosing asthma in steroid-naïve adults

Spirometry and testing for bronchodilator response have been recommended to detect asthma, and a bronchodilator response (BDR) of ≥12% and ≥200 mL has been suggested to confirm asthma. However, the clinical value of bronchodilation tests in newly diagnosed steroid-naïve adult patients with asthma remains unknown. We evaluated the sensitivity of BDR in forced expiratory volume in 1 s (FEV₁) as a diagnostic test for asthma in a real-life cohort of participants in the Seinäjoki Adult Asthma Study. In the diagnostic phase, 369 spirometry tests with bronchodilation were performed for 219 steroid-naïve patients. The fulfilment of each test threshold was assessed. According to the algorithm of the National Institute for Health and Care Excellence, we divided the patients into obstructive (FEV₁/forced vital capacity (FVC) <0.70) and non-obstructive (FEV₁/FVC ≥0.70) groups. Of the overall cohort, 35.6% fulfilled ΔFEV₁ ≥12% and ≥200 mL for the initial FEV₁, 18.3% fulfilled ΔFEV₁ ≥15% and ≥400 mL for the initial FEV₁, and 36.1% fulfilled ΔFEV₁ ≥9% of predicted FEV₁ at least once. One-third (31%) of these steroid-naïve patients was obstructive (pre-bronchodilator FEV₁/FVC <0.7). Of the obstructive patients, 55.9%, 26.5% and 48.5%, respectively, met the same thresholds. In multivariate logistic regression analysis, different thresholds recognised different kinds of asthma patients. In steroid-naïve adult patients, the current BDR threshold (ΔFEV₁ ≥12% and ≥200 mL) has low diagnostic sensitivity (36%) for asthma. In obstructive patients, sensitivity is somewhat higher (56%) but far from optimal. If the first spirometry test with bronchodilation is not diagnostic but asthma is suspected, spirometry should be repeated, and other lung function tests should be used to confirm the diagnosis.

Residual Volume Responsiveness Testing May Improve the Detection of Reversible Airway Obstruction in Asthma

BACKGROUND

Residual volume responsiveness to bronchodilator administration has been observed in subjects with chronic obstructive pulmonary disease. However, the prevalence of residual volume (RV) responsiveness has not been formally studied in asthma.

OBJECTIVE

To identify the prevalence and magnitude of RV responsiveness in asthma.

METHODS

Physician-diagnosed adult subjects with asthma on treatment for >12 months were prospectively recruited to perform spirometry and measurement of lung volumes using body plethysmography before and after administration of 360 μg of albuterol.

RESULTS

Among 120 subjects, 76% were women. The ethnic composition was 64% Caucasian, 32% Hispanic, and 13% African American. The mean age was 52 ± 15 years. The mean duration of asthma was 16 ± 15 years. The mean RV% responsiveness was -7.74 ± 14. Whereas patients with the lowest baseline forced expiratory volume in 1 second (FEV1) value showed the highest mean responsiveness (P = .001), the baseline RV value had minimal influence on RV responsiveness. Using -7.74% to define significant RV responsiveness, and ≥12% and ≥200 mL to define significant FEV1 responsiveness, more subjects showed isolated RV responsiveness (37%) compared with 6% with isolated FEV1 responsiveness and 14% with both FEV1 and RV responsiveness (P = .04). There was a minimal correlation between FEV1 responsiveness and RV responsiveness (r = 0.17, P = .06). The RV responsiveness was significantly associated with the wheeze score (P = .006) and dyspnea score (P = .029).

CONCLUSION

The addition of RV responsiveness testing to spirometry based responsiveness testing can improve the identification of reversible airway obstruction in asthma. RV responsiveness may be useful in monitoring symptoms associated with air trapping in asthma.

IL-1β augments TGF-β inducing epithelial-mesenchymal transition of epithelial cells and associates with poor pulmonary function improvement in neutrophilic asthmatics

Background

Neutrophilic asthmatics (NA) have less response to inhaled corticosteroids. We aimed to find out the predictor of treatment response in NA.

Methods

Asthmatics (n = 115) and healthy controls (n = 28) underwent clinical assessment during 6-month follow-up with standardized therapy. Asthmatics were categorized by sputum differential cell count. The mRNA expressions were measured by RT-qPCR for sputum cytokines (IFN-γ, IL-1β, IL-27, FOXP3, IL-17A, and IL-5). The protein of IL-1β in sputum supernatant was detected by ELISA. Reticular basement membranes (RBM) were measured in the biopsy samples. The role and signaling pathways of IL-1β mediating the epithelial-mesenchymal transition (EMT) process were explored through A549 cells.

Results

NA had increased baseline sputum cell IL-1β expression compared to eosinophilic asthmatics (EA). After follow-up, NA had less improvement in FEV₁ compared to EA. For all asthmatics, sputum IL-1β mRNA was positively correlated with protein expression. Sputum IL-1β mRNA and protein levels were negatively correlated to FEV₁ improvement. After subgrouping, the correlation between IL-1β mRNA and FEV₁ improvement was significant in NA but not in EA. Thickness of RBM in asthmatics was greater than that of healthy controls and positively correlated with neutrophil percentage in bronchoalveolar lavage fluid. In vitro experiments, the process of IL-1β augmenting TGF-β1-induced EMT cannot be abrogated by glucocorticoid or montelukast sodium, but can be reversed by MAPK inhibitors.

Conclusions

IL-1β level in baseline sputum predicts the poor lung function improvement in NA. The potential mechanism may be related to IL-1β augmenting TGF-β1-induced steroid-resistant EMT through MAPK signaling pathways.

Trial registration: This study was approved by the Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (IRB ID: 20150406).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01808-7.

ARTP statement on pulmonary function testing 2020

The Association for Respiratory Technology & Physiology (ARTP) last produced a statement on the performance of lung function testing in 1994. At that time the focus was on a practical statement for people working in lung function laboratories. Since that time there have been many technological advances and alterations to best practice in the measurement and interpretation of lung function assessments. In light of these advances an update was warranted. ARTP, therefore, have provided within this document, where available, the most up-to-date and evidence-based recommendations for the most common lung function assessments performed in laboratories across the UK. These recommendations set out the requirements and considerations that need to be made in terms of environmental and patient factors that may influence both the performance and interpretation of lung function tests. They also incorporate procedures to ensure quality assured diagnostic investigations that include those associated with equipment, the healthcare professional conducting the assessments and the results achieved by the subject. Each section aims to outline the common parameters provided for each investigation, a brief principle behind the measurements (where applicable), and suggested acceptability and reproducibility criteria.

The 'clinically significant' bronchodilator responsiveness (BDR) in children: a comparative study between six definitions of scholarly societies and a mini-review

Objective: To compare the percentages of children with and without airway obstruction (obstructive and non-obstructive groups, respectively) presenting a 'clinically significant' BDR according to the following definitions: GINA: FEV₁ increase >12% predicted (∆_Predicted), ATS/ERS: FEV₁ increase ≥12% initial (∆_Initial) and ∆FEV₁ absolute (∆) ≥200 ml and/or ∆FVC_Initial ≥12% and ∆FVC ≥200 ml, British thoracic society (BTS): ∆FEV_1Initial ≥12%, National asthma education and prevention program (NAEPP): ∆FEV_1Initial ≥12% and ∆FEV₁ > 200 ml, Group of research on advances in pediatric pneumology: ∆FEV_1Initial ≥12% or ∆PEF_Initial ≥20%, and South African thoracic society (SATS): ∆FEV_1Initial ≥12% or ∆FEV₁ >200 ml and/or ∆FVC_Initial ≥12% or ∆FVC >200 ml.Methods: This was a multicenter comparative study involving 278 children aged 6 to16 years: obstructive group (FEV₁/FVC < lower-limit-of-normal, n = 116) and non-obstructive group (FEV₁/FVC ≥ lower-limit-of-normal, n = 162). Spirometry was performed before/after a bronchodilator test. The Cochrane Q test was used to compare the percentage of responders according to the six definitions.Results: The percentages of responders among the obstructive [ranging from 51.72 (NAEPP) to 74.14% (SATS)] and the non-obstructive [ranging from 0.62 (NAEPP, BTS) to 8.64% (SATS)] groups were definition-dependent.Conclusion: In children, a 'clinically significant' BDR is definition-dependent.

Assessing bronchodilator response by changes in per cent predicted forced expiratory volume in one second

In pulmonary function testing by spirometry, bronchodilator responsiveness (BDR) evaluates the degree of volume and airflow improvement in response to an inhaled short-acting bronchodilator (BD). The traditional, binary categorization (present vs absent BDR) has multiple pitfalls and limitations. To overcome these limitations, a novel classification that defines five categories (negative, minimal, mild, moderate and marked BDR), and based on % and absolute changes in forced expiratory volume in 1 s (FEV₁), has been recently developed and validated in patients with chronic obstructive pulmonary disease, and against multiple objective and subjective measurements. In this study, working on several large spirometry cohorts from two different institutions (n=31 598 tests), we redefined the novel BDR categories based on delta post-BD–pre-BD FEV₁ % predicted values. Our newly proposed BDR partition is based on several distinct intervals for delta post-BD–pre-BD % predicted FEV₁ using Global Lung Initiative predictive equations. In testing, training and validation cohorts, the model performed well in all BDR categories. In a validation set that included only normal baseline spirometries, the partition model had a higher rate of misclassification, possibly due to unrestricted BD use prior to baseline testing. A partition that uses delta % predicted FEV₁ with the following intervals ≤0%, 0%–2%, 2%–4%, 4%–8% and >8% may be a valid and easy-to-use tool for assessing BDR in spirometry. We confirmed in our cohorts that these thresholds are characterized by low variance and that they are generally gender-independent and race-independent. Future validation in other cohorts and in other populations is needed.

Combined Forced Expiratory Volume in 1 Second and Forced Vital Capacity Bronchodilator Response, Exacerbations, and Mortality in Chronic Obstructive Pulmonary Disease

Rationale: The American Thoracic Society (ATS)/European Respiratory Society defines a positive bronchodilator response (BDR) by a composite of BDR in either forced expiratory volume in 1 second (FEV₁) and/or forced vital capacity (FVC) greater than or equal to 12% and 200 ml (ATS-BDR). We hypothesized that ATS-BDR components would be differentially associated with important chronic obstructive pulmonary disease (COPD) outcomes. Objectives: To examine whether ATS-BDR components are differentially associated with clinical, functional, and radiographic features in COPD. Methods: We included subjects with COPD enrolled in the COPDGene study. In the main analysis, we excluded subjects with self-reported asthma. We categorized BDR into the following: 1) No-BDR, no BDR in either FEV₁ or FVC; 2) FEV₁-BDR, BDR in FEV₁ but no BDR in FVC; 3) FVC-BDR, BDR in FVC but no BDR in FEV₁; and 4) Combined-BDR, BDR in both FEV₁ and FVC. We constructed multivariable logistic, linear, zero-inflated negative binomial, and Cox hazards models to examine the association of BDR categories with symptoms, computed tomography findings, change in FEV₁ over time, respiratory exacerbations, and mortality. We also created models using the ATS BDR definition (ATS-BDR) as the main independent variable. Results: Of 3,340 COPD subjects included in the analysis, 1,083 (32.43%) had ATS-BDR, 182 (5.45%) had FEV₁-BDR, 522 (15.63%) had FVC-BDR, and 379 (11.34%) had Combined-BDR. All BDR categories were associated with FEV₁ decline compared with No-BDR. Compared with No-BDR, both ATS-BDR and Combined-BDR were associated with higher functional residual capacity %predicted, greater internal perimeter of 10 mm, and greater 6-minute-walk distance. In contrast to ATS-BDR, Combined-BDR was independently associated with less emphysema (adjusted beta regression coefficient, -1.67; 95% confidence interval [CI], -2.68 to -0.65; P = 0.001), more frequent respiratory exacerbations (incidence rate ratio, 1.25; 95% CI, 1.03-1.50; P = 0.02) and severe exacerbations (incidence rate ratio, 1.34; 95% CI, 1.05-1.71; P = 0.02), and lower mortality (adjusted hazards ratio, 0.76; 95% CI, 0.58-0.99; P = 0.046). Sensitivity analysis that included subjects with self-reported history of asthma showed similar findings. Conclusions: BDR in both FEV₁ and FVC indicates a COPD phenotype with asthma-like characteristics, and provides clinically more meaningful information than current definitions of BDR.

Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement

Background: Spirometry is the most common pulmonary function test. It is widely used in the assessment of lung function to provide objective information used in the diagnosis of lung diseases and monitoring lung health. In 2005, the American Thoracic Society and the European Respiratory Society jointly adopted technical standards for conducting spirometry. Improvements in instrumentation and computational capabilities, together with new research studies and enhanced quality assurance approaches, have led to the need to update the 2005 technical standards for spirometry to take full advantage of current technical capabilities.Methods: This spirometry technical standards document was developed by an international joint task force, appointed by the American Thoracic Society and the European Respiratory Society, with expertise in conducting and analyzing pulmonary function tests, laboratory quality assurance, and developing international standards. A comprehensive review of published evidence was performed. A patient survey was developed to capture patients' experiences.Results: Revisions to the 2005 technical standards for spirometry were made, including the addition of factors that were not previously considered. Evidence to support the revisions was cited when applicable. The experience and expertise of task force members were used to develop recommended best practices.Conclusions: Standards and consensus recommendations are presented for manufacturers, clinicians, operators, and researchers with the aims of increasing the accuracy, precision, and quality of spirometric measurements and improving the patient experience. A comprehensive guide to aid in the implementation of these standards was developed as an online supplement.

A New Bronchodilator Response Grading Strategy Identifies Distinct Patient Populations

Rationale: A positive bronchodilator response (BDR) according to American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines require both 200 ml and 12% increase in forced expiratory volume in 1 second (FEV1) or forced vital capacity (FVC) after bronchodilator inhalation. This dual criterion is insensitive in those with high or low FEV1.Objectives: To establish BDR criteria with volume or percentage FEV1 change.Methods: The largest FEV1 and FVC were identified from three pre- and three post-bronchodilator maneuvers in COPDGene (Genetic Epidemiology of COPD) participants. A total of 7,741 individuals with coefficient of variation less than 15% for both FEV1 and FVC formed bronchodilator categories of FEV1 response: negative (≤0.00% or ≤0.00 L), minimal (>0.00% to ≤9.00% or >0.00 L to ≤0.09 L), mild (>9.00% to ≤16.00% or >0.09 L to ≤0.16 L), moderate (>16.00% to ≤26.00% or >0.16 L to ≤0.26 L), and marked (>26.00% or >0.26 L). These response size categories are based on empirical limits considering average FEV1 increase of approximately 160 ml and the clinically important difference for FEV1. To compare flow and volume response characteristics, BDR-FEV1 category assignments were applied for the BDR-FVC response.Results: Twenty percent met mild and 31% met moderate or marked BDR-FEV1 criteria, whereas 12% met mild and 33% met moderate or marked BDR-FVC criteria. In contrast, only 20.6% met ATS/ERS positive criteria. Compared with the negative BDR-FEV1 category, the minimal, mild, moderate, and marked BDR-FEV1 categories were associated with greater 6-minute-walk distance and lower St. George's Respiratory Questionnaire and modified Medical Research Council dyspnea scale scores. Compared with negative BDR, moderate and marked BDR-FEV1 categories were associated with fewer exacerbations, and minimal BDR was associated with lower computed tomography airway wall thickness. Compared with the negative category, all BDR-FVC categories were associated with increasing emphysema percentage and gas trapping percentage. Moderate and marked BDR-FVC categories were associated with higher St. George's Respiratory Questionnaire scores but fewer exacerbations and lower dyspnea scores.Conclusions: BDR grading by FEV1 volume or percentage response identified subjects otherwise missed by ATS/ERS criteria. BDR grades were associated with functional exercise performance, quality of life, exacerbation frequency, dyspnea, and radiological airway measures. BDR grades in FEV1 and FVC indicate different clinical and radiological characteristics.

Clinical significance of the bronchodilator response in children with severe asthma

BACKGROUND

Our objective was to determine those characteristics associated with reversibility of airflow obstruction and response to maximal bronchodilation in children with severe asthma through the Severe Asthma Research Program (SARP).

METHODS

We performed a cross-sectional analysis evaluating children ages 6 to 17 years with nonsevere asthma (NSA) and severe asthma (SA). Participants underwent spirometry before and after 180 µg of albuterol to determine reversibility (≥12% increase in FEV₁ ). Participants were then given escalating doses up to 720 µg of albuterol to determine their maximum reversibility.

RESULTS

We evaluated 230 children (n = 129 SA, n = 101 NSA) from five centers across the United States in the SARP I and II cohorts. SA (odds ratio [OR], 2.08, 95% confidence interval [CI], 1.05-4.13), second-hand smoke exposure (OR, 2.81, 95%CI, 1.23-6.43), and fractional exhaled nitric oxide (FeNO; OR, 1.97, 95%CI, 1.35-2.87) were associated with increased odds of airway reversibility after maximal bronchodilation, while higher prebronchodilator (BD) FEV₁ % predicted (OR, 0.91, 95%CI, 0.88-0.94) was associated with decreased odds. In an analysis using the SARP III cohort (n = 186), blood neutrophils, immunoglobulin E (IgE), and FEV₁ % predicted were significantly associated with BD reversibility. In addition, children with BD response have greater healthcare utilization. BD reversibility was associated with reduced lung function at enrollment and 1-year follow-up though less decline in lung function over 1 year compared to those without reversibility.

CONCLUSIONS

Lung function, that is FEV₁ % predicted, is a predictor of BD response in children with asthma. Additionally, smoke exposure, higher FeNO or IgE level, and low peripheral blood neutrophils are associated with a greater likelihood of BD reversibility. BD response can identify a phenotype of pediatric asthma associated with low lung function and poor asthma control.

Development and initial validation of the Asthma Severity Scoring System (ASSESS)

BACKGROUND

Tools for quantification of asthma severity are limited.

OBJECTIVE

We sought to develop a continuous measure of asthma severity, the Asthma Severity Scoring System (ASSESS), for adolescents and adults, incorporating domains of asthma control, lung function, medications, and exacerbations.

METHODS

Baseline and 36-month longitudinal data from participants in phase 3 of the Severe Asthma Research Program (NCT01606826) were used. Scale properties, responsiveness, and a minimally important difference were determined. External replication was performed in participants enrolled in the Severe Asthma Research Program phase 1/2. The utility of ASSESS for detecting treatment response was explored in participants undergoing corticosteroid responsiveness testing with intramuscular triamcinolone and participants receiving biologics.

RESULTS

ASSESS scores ranged from 0 to 20 (8.78 ± 3.9; greater scores reflect worse severity) and differed among 5 phenotypic groups. Measurement properties were acceptable. ASSESS was responsive to changes in quality of life with a minimally important difference of 2, with good specificity for outcomes of asthma improvement and worsening but poor sensitivity. Replication analyses yielded similar results, with a 2-point decrease (improvement) associated with improvements in quality of life. Participants with a 2-point or greater decrease (improvement) in ASSESS scores also had greater improvement in lung function and asthma control after triamcinolone, but these differences were limited to phenotypic clusters 3, 4, and 5. Participants treated with biologics also had a 2-point or greater decrease (improvement) in ASSESS scores overall.

CONCLUSIONS

The ASSESS tool is an objective measure that might be useful in epidemiologic and clinical research studies for quantification of treatment response in individual patients and phenotypic groups. However, validation studies are warranted.

Joint Indian Chest Society-National College of Chest Physicians (India) guidelines for spirometry

Although a simple and useful pulmonary function test, spirometry remains underutilized in India. The Indian Chest Society and National College of Chest Physicians (India) jointly supported an expert group to provide recommendations for spirometry in India. Based on a scientific grading of available published evidence, as well as other international recommendations, we propose a consensus statement for planning, performing and interpreting spirometry in a systematic manner across all levels of healthcare in India. We stress the use of standard equipment, and the need for quality control, to optimize testing. Important technical requirements for patient selection, and proper conduct of the vital capacity maneuver, are outlined. A brief algorithm to interpret and report spirometric data using minimal and most important variables is presented. The use of statistically valid lower limits of normality during interpretation is emphasized, and a listing of Indian reference equations is provided for this purpose. Other important issues such as peak expiratory flow, bronchodilator reversibility testing, and technician training are also discussed. We hope that this document will improve use of spirometry in a standardized fashion across diverse settings in India.

Depressive symptom-associated IL-1β and TNF-α release correlates with impaired bronchodilator response and neutrophilic airway inflammation in asthma

BACKGROUND

Depressive symptoms worsen asthma outcomes; however, the mechanism remains largely unexplored.

OBJECTIVE

This study aimed to determine whether depressive symptom-associated immune inflammation correlates with impaired bronchodilator response (BDR) and airway inflammatory phenotypes.

METHODS

Eligible adults with asthma (n = 198) underwent clinical assessment, sputum induction and blood sampling. Depressive symptoms were defined by scores on the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D). Pre- and post-bronchodilator spirometry was performed for BDR. Airway inflammatory phenotypes were defined by sputum cell counts. CRP, IL-1β, IL-5, IL-6, IL-8, TNF-α, IFN-γ, CCL17 and CCL22 in serum and sputum were detected.

RESULTS

Compared with the non-depressive group (n = 174), the depressive group (n = 24) exhibited impaired BDR (P = 0.032) and increased sputum neutrophils (P = 0.023), which correlated with the HADS-D scores (P = 0.027 and P = 0.029). Levels of IL-1β, TNF-α and IFN-γ in the serum and those of IL-1β and IFN-γ in the sputum were elevated in the depressive group compared to those in the non-depressive group (all P < 0.05). Multiple regression models indicated that TNF-α in the sputum and IL-1β, IL-6 and IFN-γ in both the serum and sputum were inversely associated with BDR; TNF-α in the sputum and IL-1β in both the serum and sputum were positively correlated with sputum neutrophils. Mediation analyses revealed that IL-1β and TNF-α in the sputum and IL-1β in both the serum and sputum mediate the correlations of the HADS-D scores with BDR and sputum neutrophils, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Asthma patients with depressive symptoms present worse asthma control, which is most likely explained by impaired BDR and neutrophilic airway inflammation. IL-1β and TNF-α, which are two key pro-inflammatory cytokines that mediate the correlation of depressive symptoms with impaired BDR and neutrophilic airway inflammation, may serve as targeted biomarkers in the neuropsychological phenotype of asthma; however, this result needs to be further validated.

Immediate bronchodilator response in FEV1 as a diagnostic criterion for adult asthma

Asthma is characterised by variable and reversible expiratory airflow limitations. Thus, it is logical to use the change in forced expiratory volume in 1 s (FEV₁) in response to a bronchodilator (ΔFEV₁BDR) as a diagnostic tool; increases of ≥12% and ≥200 mL from the baseline FEV₁ are commonly used values. We aimed to evaluate the historical development of diagnostic cut-off levels for the ΔFEV₁BDR for adults and the evidence behind these recommendations.We searched for studies from the reference lists of all the main statements, reports and guidelines concerning the interpretation of spirometry and diagnostics for asthma and conducted a literature search.A limited amount of evidence regarding the ΔFEV₁BDR in healthy populations was found, and even fewer patient studies were found. In healthy persons, the upper 95th percentile for the absolute ΔFEV₁BDR ranges between 240 mL and 320 mL, the relative ΔFEV₁BDR calculated from the initial FEV₁ ranges from 5.9% to 13.3% and the ΔFEV₁BDR calculated from the predicted FEV₁ ranges from 8.7% to 11.6%. However, the absolute and percentage ΔFEV₁BDR values calculated from the initial FEV₁ are dependent on age, sex, height and the degree of airway obstruction. Thus, the use of the ΔFEV₁BDR calculated from the predicted FEV₁ might be more appropriate.Not enough data exist to assess the sensitivity of any of the cut-off levels for the ΔFEV₁BDR to differentiate asthma patients from healthy subjects. Further studies in newly diagnosed asthma patients are needed.

Impulse oscillometry and spirometry exhibit different features of lung function in bronchodilation

OBJECTIVE

Bronchodilator responses (BDRs) from impulse oscillometry (IOS) are not interchangeable with those from spirometry. We aimed to identify the characteristics of children with small airway hyperresponsiveness and to determine whether BDR from IOS provides an important supplement to BDR from spirometry.

METHODS

The records of 592 children with asthma or suspected asthma who underwent spirometric and oscillometric BDRs were retrospectively reviewed. Oscillometric BDR was defined as positive when relative or absolute changes of Rrs₅ or Xrs₅ were beyond two standard deviations and spirometric BDR as positive when absolute change of forced expiratory volume in one second (FEV₁) was ≥12%. Subjects were classified as positive for spirometric BDR only, positive for oscillometric BDR only, positive for both BDRs, or negative for both BDRs.

RESULTS

The results indicated that 101 (17.6%) subjects were positive for spirometric BDR only, 49 (8.5%) positive for oscillometric BDR only, 48 (8.3%) positive for both BDRs, and 377 (65.6%) negative for both BDRs. The agreement between spirometric and oscillometric BDRs was poor. Baseline FEV₁, Rrs₅, and Xrs₅ values strongly influenced the BDRs. Subjects positive for oscillometric BDR only were found to be younger than those positive for spirometric BDR only (P < 0.001). Subjects positive for both BDRs were more likely to have asthma, atopic dermatitis, wheezing apart from cold, or decreased baseline lung function relative to those positive in either test (P < 0.001).

CONCLUSIONS

There was a low concordance between spirometric and oscillometric BDRs. Use of IOS to detect small airway hyperresponsiveness may add more information about a clinical profile of subjects with asthma.

Oral Versus Nasal High-Flow Bronchodilator Inhalation in Chronic Obstructive Pulmonary Disease

BACKGROUND

Nasal high flow (NHF) alters breathing patterns, stabilizes fraction of inspired oxygen (FiO2) during respiratory distress, helps to keep up hemostasis in the airways, and washes out the upper airways. Particularly the support of inspiratory flow and decrease in functional dead space are interesting mechanisms of action with regard to aerosol delivery. Several laboratory investigations have studied aerosol delivery via the nasal route by using NHF, whereas clinical benefits are poorly evaluated.

METHODS

Thirty patients with stable chronic obstructive pulmonary disease Gold D were recruited. In a randomized order, they inhaled a salbutamol 2.5 mg/ipratropium bromide 500 μg solution oral or NHF adapted on the second study day. A jet nebulizer was used as aerosol delivery device. The chosen flow rate was 35 L/min.

RESULTS

Four patients refused to repeat the procedure, for example, for inconvenience or fear of delayed discharge, and were not included in the intention-to-treat analysis. All remaining patients tolerated both inhalation systems well. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), airway resistance (Rtot), and residual volume (RV) were significantly altered after bronchodilator inhalation with each of the both devices. The two different ways of combined bronchodilator inhalation resulted in very comparable changes in FVC, FEV1, relative 1 second-capacity (FEV1%FVC), Rtot, total lung capacity (TLC), RV, and residual volume expressed as percent of TLC (RV%TLC). However, in between devices, no difference was observed on comparing the postinhalational measurements of FVC, FEV1, Rtot, and RV.

CONCLUSIONS

We conclude from this proof-of-principle kind of study that inhalation of combined bronchodilators adapted to an NHF device is similarly effective to inhalation with a standard oral aerosol nebulizer. (Clinical Trails NCT02885103).

Inflammatory and Comorbid Features of Patients with Severe Asthma and Frequent Exacerbations

RATIONALE

Reducing asthma exacerbation frequency is an important criterion for approval of asthma therapies, but the clinical features of exacerbation-prone asthma (EPA) remain incompletely defined.

OBJECTIVES

To describe the clinical, physiologic, inflammatory, and comorbidity factors associated with EPA.

METHODS

Baseline data from the NHLBI Severe Asthma Research Program (SARP)-3 were analyzed. An exacerbation was defined as a burst of systemic corticosteroids lasting 3 days or more. Patients were classified by their number of exacerbations in the past year: none, few (one to two), or exacerbation prone (≥3). Replication of a multivariable model was performed with data from the SARP-1 + 2 cohort.

MEASUREMENTS AND MAIN RESULTS

Of 709 subjects in the SARP-3 cohort, 294 (41%) had no exacerbations and 173 (24%) were exacerbation prone in the prior year. Several factors normally associated with severity (asthma duration, age, sex, race, and socioeconomic status) did not associate with exacerbation frequency in SARP-3; bronchodilator responsiveness also discriminated exacerbation proneness from asthma severity. In the SARP-3 multivariable model, blood eosinophils, body mass index, and bronchodilator responsiveness were positively associated with exacerbation frequency (rate ratios [95% confidence interval], 1.6 [1.2-2.1] for every log unit of eosinophils, 1.3 [1.1-1.4] for every 10 body mass index units, and 1.2 [1.1-1.4] for every 10% increase in bronchodilatory responsiveness). Chronic sinusitis and gastroesophageal reflux were also associated with exacerbation frequency (1.7 [1.4-2.1] and 1.6 [1.3-2.0]), even after adjustment for multiple factors. These effects were replicated in the SARP-1 + 2 multivariable model.

CONCLUSIONS

EPA may be a distinct susceptibility phenotype with implications for the targeting of exacerbation prevention strategies. Clinical trial registered with www.clinicaltrials.gov (NCT 01760915).

Effects of Age and Disease Severity on Systemic Corticosteroid Responses in Asthma

RATIONALE

Phenotypic distinctions between severe asthma (SA) and nonsevere asthma (NONSA) may be confounded by differential adherence or incorrect use of corticosteroids.

OBJECTIVES

To determine if there are persistent phenotypic distinctions between SA (as defined by 2014 American Thoracic Society/European Respiratory Society guidelines) and NONSA after intramuscular triamcinolone acetonide (TA), and to identify predictors of a corticosteroid response in these populations.

METHODS

A total of 526 adults age 18 years and older (315 SA) and 188 children age 6 to less than 18 years (107 SA) in the NHLBI Severe Asthma Research Program III were characterized before and 3 weeks after TA. The primary outcome for corticosteroid response was defined as greater than or equal to 10-point improvement in percent predicted FEV1.

MEASUREMENTS AND MAIN RESULTS

Adult asthma groups exhibited a small but significant mean FEV1% predicted improvement after TA (SA group mean difference, 3.4%; 95% confidence interval, 2.2-4.7%; P = 0.001), whereas children did not. Adult SA continued to manifest lower FEV1 and worse asthma control as compared with NONSA after TA. In children, after TA only prebronchodilator FEV1 distinguished SA from NONSA. A total of 21% of adults with SA and 20% of children with SA achieved greater than or equal to 10% improvement after TA. Baseline bronchodilator response and fractional exhaled nitric oxide had good sensitivity and specificity for predicting response in all groups except children with NONSA.

CONCLUSIONS

One in five patients with SA exhibit greater than or equal to 10% improvement in FEV1 with parenteral corticosteroid. Those likely to respond had greater bronchodilator responsiveness and fractional exhaled nitric oxide levels. In adults, differences in airflow obstruction and symptoms between SA and NONSA persist after parenteral corticosteroids, suggesting a component of corticosteroid nonresponsive pathobiology in adults with SA that may differ in children. Clinical trial registered with www.clinicaltrials.gov (NCT 01606826).

Which bronchodilator reversibility criteria can predict severe acute exacerbation in chronic obstructive pulmonary disease patients?

BACKGROUND

It is unclear whether various bronchodilator reversibility (BDR) criteria affect the prognosis of chronic obstructive pulmonary disease (COPD). The aim of this study is to evaluate the impact of positive BDR defined according to various BDR criteria on the risk of severe acute exacerbation (AE) in COPD patients.

METHODS

Patients from four prospective COPD cohorts in South Korea who underwent follow-up for at least 1 year were enrolled in this study. The assessed BDR criteria included the Global Initiative for Chronic Obstructive Lung Disease (GOLD), American Thoracic Society (ATS), American College of Chest Physicians, (ACCP), major criteria of the Spanish definition of asthma-COPD overlap syndrome (ACOS), criteria compatible with ACOS in the Global Initiative for Asthma (GINA), and European Respiratory Society (ERS). The rate of patients with severe AE who required hospitalization within 1 year due to BDR results according to each set of criteria was analyzed using logistic regression models.

RESULTS

Among a total of 854 patients, the BDR-positive cases varied according to the criteria used. There was a 3.5% positive BDR rate according to GINA and a 29.9% rate according to the ATS criteria. Positive BDR according to the GOLD criteria was significantly associated with a decreased risk of severe AE (adjusted odds ratio (aOR) = 0.38; 95% Confidence interval (CI) = 0.15-0.93). This result remained statistically significant even in a sensitivity analysis that included only participants with a smoking history of at least 10 pack-years and in the analysis for the propensity score-matched participants.

CONCLUSIONS

Among different criteria for positive BDR, the use of the GOLD ones was significantly associated with a decreased risk of severe AE in COPD patients. Increase use of ICS/LABA may have affected this relationship.

Measures of bronchodilator response of FEV1, FVC and SVC in a Swedish general population sample aged 50-64 years, the SCAPIS Pilot Study

BACKGROUND

Data are lacking from general population studies on how to define changes in lung function after bronchodilation. This study aimed to analyze different measures of bronchodilator response of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and slow vital capacity (SVC).

MATERIALS AND METHODS

Data were derived from the Swedish Cardiopulmonary Bioimage Study (SCAPIS) Pilot study. This analysis comprised 1,050 participants aged 50-64 years from the general population. Participants were investigated using a questionnaire, and FEV1, FVC and SVC were recorded before and 15 minutes after inhalation of 400 µg of salbutamol. A bronchodilator response was defined as the relative change from baseline value expressed as the difference in units of percent predicted normal. Predictors of bronchodilator responses were assessed using multiple linear regression models. Airway obstruction was defined as FEV1/FVC ratio below lower limit of normal (LLN) before bronchodilation, and COPD was defined as an FEV1/FVC ratio below LLN after bronchodilation. Physician-diagnosed asthma was defined as an affirmative answer to "Have you ever had asthma diagnosed by a physician?". Asymptomatic never-smokers were defined as those not reporting physician-diagnosed asthma, physician-diagnosed COPD or emphysema, current wheeze or chronic bronchitis and being a lifelong never-smoker.

RESULTS

Among all subjects, the greatest bronchodilator responses (FEV1, FVC and SVC) were found in subjects with asthma or COPD. The upper 95th percentile of bronchodilator responses in asymptomatic never-smokers was 8.7% for FEV1, 4.2% for FVC and 5.0% for SVC. The bronchodilator responses were similar between men and women. In a multiple linear regression model comprising all asymptomatic never-smokers, the bronchodilator response of FEV1 was significantly associated with airway obstruction and height.

CONCLUSION

When the bronchodilator response in asymptomatic never-smokers is reported as the difference in units of predicted normal, significant reversibility of FEV1, FVC and SVC to bronchodilators is ~9%, 4% and 5%, respectively.

Bronchodilator Response in FVC Is Larger and More Relevant Than in FEV1 in Severe Airflow Obstruction

BACKGROUND

Recommendations on interpreting tests of bronchodilator responsiveness (BDR) are conflicting. We investigated the dependence of BDR criteria on sex, age, height, ethnicity, and severity of respiratory impairment.

METHODS

BDR test data were available from clinical patients in the Netherlands, New Zealand, and the United States (n = 15,278; female subjects, 51.7%) and from surveys in Canada, Norway, and five Latin-American countries (n = 16,250; female subjects, 54.7%). BDR calculated according to FEV₁, FVC, and FEV₁/FVC was expressed as absolute change, a percentage of the baseline level (% baseline), a percentage of the predicted value (% predicted), and z score.

RESULTS

Change (Δ) in FEV₁ and FVC, in milliliters, was unrelated to the baseline value but was biased toward age, height, sex, and level of airways obstruction; ΔFEV₁ was significantly lower in African Americans. In 1,106 subjects with low FEV₁ (200-1,621 mL) the FEV₁ increased by 12% to 44.7% relative to baseline but < 200 mL. Expressing BDR as a percentage of the predicted value or as a z score attenuated the bias and made the 200-mL criterion redundant, but reduced positive responses by half. ΔFEV₁ % baseline increased with the level of airflow obstruction but decreased with severe obstruction when expressed as z scores or % predicted; ΔFVC, however expressed, increased with the level of airflow obstruction.

CONCLUSIONS

Expressing FEV₁ responsiveness as % baseline spuriously suggests that responsiveness increases with the severity of respiratory impairment. Expressing change in FEV₁ or FVC as % predicted or as z scores eliminates this artifact and renders the required 200-mL minimum increase redundant. In severe airways obstruction ΔFVC should be critically evaluated as an index of clinically important relief of hyperinflation, with implications for bronchodilator drug trials.