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

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.

Prevalence of Bronchodilator Responsiveness: A Comparison of Old Versus New Criteria

BACKGROUND

In 2021, the European Respiratory Society (ERS)/American Thoracic Society (ATS) guidelines issued a new definition of bronchodilator responsiveness, which is now defined as an increase in FEV1 or FVC by ≥ 10% of the predicted FEV1 or FVC. The impact of this revised definition on bronchodilator responsiveness prevalence has been relatively understudied.

METHODS

We retrospectively analyzed data from 2,696 subjects who performed pulmonary function testing at the University of Iowa from 1997 to 2018. We compared the prevalence of bronchodilator responsiveness by using the 2005 (FEV1 or FVC increase ≥ 12% baseline value and ≥ 200 mL) and 2021 (FEV1 or FVC increase ≥ 200 mL and ≥ 12% of baseline value) ERS/ATS definitions, across several different respiratory diagnosis categories. We compared the prevalence of bronchodilator responsiveness using the 2 definitions by applying the McNemar test and assessed concordance of bronchodilator responsiveness by calculating kappa coefficients for the whole study population and within each diagnosis category.

RESULTS

The prevalence of bronchodilator responsiveness increased from 9% when using the 2005 ERS/ATS definition to 16% when using the 2021 definition within the entire cohort and also within each respiratory diagnosis category. In the subjects with normal pre-bronchodilator spirometry, there was a low prevalence of bronchodilator responsiveness (3%) when using the 2005 definition, and the prevalence increased (8%) when using the 2021 definition. In the subjects with normal pre-bronchodilator spirometry and FEV1 Z score ≥ 0, 2% had bronchodilator responsivness according to the 2005 guidelines, whereas 7% had bronchodilator responsiveness according to the 2021 guidelines.

CONCLUSIONS

The prevalence of bronchodilator responsiveness increased when using the new 2021 ERS/ATS definition compared with the 2005 definition. In the subjects with normal pre-bronchodilator spirometry, the prevalence of bronchodilator responsiveness increased when using the 2021 definition, in particular, among those with an FEV1 Z score ≥ 0, which raises concerns for overdiagnosis. Future investigations should examine the correlation of bronchodilator responsiveness with clinical outcomes in this group of subjects.

Post-discharge spirometry evaluation in patients recovering from moderate-to-critical COVID-19: a cross-sectional study

Understanding the prevalence of abnormal lung function and its associated factors among patients recovering from COVID-19 is crucial for enhancing post-COVID care strategies. This study primarily aimed to determine the prevalence and types of spirometry abnormalities among post-COVID-19 patients in Malaysia, with a secondary objective of identifying its associated factors. Conducted at the COVID-19 Research Clinic, Faculty of Medicine, University Technology MARA, from March 2021 to December 2022, this study included patients at least three months post-discharge from hospitals following moderate-to-critical COVID-19. Of 408 patients studied, abnormal spirometry was found in 46.8%, with 28.4% exhibiting a restrictive pattern, 17.4% showing preserved ratio impaired spirometry (PRISm), and 1.0% displaying an obstructive pattern. Factors independently associated with abnormal spirometry included consolidation on chest X-ray (OR 8.1, 95% CI 1.75-37.42, p = 0.008), underlying cardiovascular disease (OR 3.5, 95% CI 1.19-10.47, p = 0.023), ground-glass opacity on chest X-ray (OR 2.6, 95% CI 1.52-4.30, p < 0.001), and oxygen desaturation during the 6-min walk test (OR 1.9, 95% CI 1.20-3.06, p = 0.007). This study highlights that patients recovering from moderate-to-critical COVID-19 often exhibit abnormal spirometry, notably a restrictive pattern and PRISm. Routine spirometry screening for high-risk patients is recommended.

Walking or breathing: comparing the 6-minute walking distance test to the pulmonary function test for lung resection candidates

INTRODUCTION

Given the limited use of the 6-minute walking distance (6MWD) test as a replacement for standard tests in thoracic surgery, insufficient research exists on the prognostic value of this test, and further studies are necessary. This study aimed to investigate the correlation between pulmonary function tests (PFT) and the 6MWD test in lung resection patients.

METHODS

This cross-sectional study, conducted in 2021-2022, involved lung resection candidates referred to the thoracic surgery clinic. Demographic data, including age, sex, and body mass index (BMI), were collected, and pulmonary function tests and 6MWD tests were conducted for all patients. The sample size of the study was 31, and all patients received routine treatment during hospitalization.

RESULTS

Of the 31 subjects included in the study, 16 were male (51.6%) and 15 (48.4%) were female. The mean age of the patients was 33.45±13.78 years. The median forced expiratory volume in one second (FEV1) and the mean ratio of FEV1/forced vital capacity (FVC) were 2.16 (1.49-2.85) liters and 81.80±7.34%, respectively. No significant correlation was found between the results of 6MWD and PFT, including FVC, FEV1, and FEV1/FVC ratio (P>0.05).

CONCLUSION

The 6MWD test is a more economical and easily accessible test than PFT. However, this study found no correlation between the 6MWD test and spirometry parameters. Therefore, we suggest that surgeons should not rely on the 6MWD test as a predictive value for assessing respiratory function in lung resection candidates. The study's findings have important implications for clinical practice.

COPD stage detection: leveraging the auto-metric graph neural network with inspiratory and expiratory chest CT images

Chronic obstructive pulmonary disease (COPD) is a common lung disease that can lead to restricted airflow and respiratory problems, causing a significant health, economic, and social burden. Detecting the COPD stage can provide a timely warning for prompt intervention in COPD patients. However, existing methods based on inspiratory (IN) and expiratory (EX) chest CT images are not sufficiently accurate and efficient in COPD stage detection. The lung region images are autonomously segmented from IN and EX chest CT images to extract the 1 , 781 × 2 lung radiomics and 13 , 824 × 2 3D CNN features. Furthermore, a strategy for concatenating and selecting features was employed in COPD stage detection based on radiomics and 3D CNN features. Finally, we combine all the radiomics, 3D CNN features, and factor risks (age, gender, and smoking history) to detect the COPD stage based on the Auto-Metric Graph Neural Network (AMGNN). The AMGNN with radiomics and 3D CNN features achieves the best performance at 89.7 % of accuracy, 90.9 % of precision, 89.5 % of F1-score, and 95.8 % of AUC compared to six classic machine learning (ML) classifiers. Our proposed approach demonstrates high accuracy in detecting the stage of COPD using both IN and EX chest CT images. This method can potentially establish an efficient diagnostic tool for patients with COPD. Additionally, we have identified radiomics and 3D CNN as more appropriate biomarkers than Parametric Response Mapping (PRM). Moreover, our findings indicate that expiration yields better results than inspiration in detecting the stage of COPD.

Chronic obstructive pulmonary disease (COPD) and COPD-like phenotypes

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease. Historically, two COPD phenotypes have been described: chronic bronchitis and emphysema. Although these phenotypes may provide additional characterization of the pathophysiology of the disease, they are not extensive enough to reflect the heterogeneity of COPD and do not provide granular categorization that indicates specific treatment, perhaps with the exception of adding inhaled glucocorticoids (ICS) in patients with chronic bronchitis. In this review, we describe COPD phenotypes that provide prognostication and/or indicate specific treatment. We also describe COPD-like phenotypes that do not necessarily meet the current diagnostic criteria for COPD but provide additional prognostication and may be the targets for future clinical trials.

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.

The utility of quantitative computed tomography in cohort studies of chronic obstructive pulmonary disease: a narrative review

Background and Objective

Chronic obstructive pulmonary disease (COPD) is a significant contributor to global morbidity and mortality. Quantitative computed tomography (QCT), a non-invasive imaging modality, offers the potential to assess lung structure and function in COPD patients. Amidst the coronavirus disease 2019 (COVID-19) pandemic, chest computed tomography (CT) scans have emerged as a viable alternative for assessing pulmonary function (e.g., spirometry), minimizing the risk of aerosolized virus transmission. However, the clinical application of QCT measurements is not yet widespread enough, necessitating broader validation to determine its usefulness in COPD management.

Methods

We conducted a search in the PubMed database in English from January 1, 2013 to April 20, 2023, using keywords and controlled vocabulary related to QCT, COPD, and cohort studies.

Key Content and Findings

Existing studies have demonstrated the potential of QCT in providing valuable information on lung volume, airway geometry, airway wall thickness, emphysema, and lung tissue density in COPD patients. Moreover, QCT values have shown robust correlations with pulmonary function tests, and can predict exacerbation risk and mortality in patients with COPD. QCT can even discern COPD subtypes based on phenotypic characteristics such as emphysema predominance, supporting targeted management and interventions.

Conclusions

QCT has shown promise in cohort studies related to COPD, since it can provide critical insights into the pathogenesis and progression of the disease. Further research is necessary to determine the clinical significance of QCT measurements for COPD management.

The Challenges of Spirometric Diagnosis of COPD

Chronic obstructive pulmonary disease (COPD) is one of the top causes of morbidity and mortality worldwide. Although for many years its accurate diagnosis has been a focus of intense research, it is still challenging. Due to its simplicity, portability, and low cost, spirometry has been established as the main tool to detect this condition, but its flawed performance makes it an imperfect COPD diagnosis gold standard. This review aims to provide an up-to-date literature overview of recent studies regarding COPD diagnosis; we seek to identify their limitations and establish perspectives for spirometric diagnosis of COPD in the XXI century by combining deep clinical knowledge of the disease with advanced computer analysis techniques.

The Role of Pulmonary Function Testing in the Diagnosis and Management of COPD

Pulmonary function testing (PFT) has a long and rich history in the definition, diagnosis, and management of COPD. For decades, spirometry has been regarded as the standard for diagnosing COPD; however, numerous studies have shown that COPD symptoms, pathology, and associated poor outcomes can occur, despite normal spirometry. Diffusing capacity and imaging studies have called into question the need for spirometry to put the "O" (obstruction) in COPD. The role of exercise testing and the ability of PFTs to phenotype COPD are reviewed. Although PFTs play an important role in diagnosis, treatment decisions are primarily determined by symptom intensity and exacerbation history. Although a seminal study positioned FEV1 as the primary predictor of survival, numerous studies have shown that tests other than spirometry are superior predictors of mortality. In years past, using spirometry to screen for COPD was promulgated; however, this only seems appropriate for individuals who are symptomatic and at risk for developing COPD.

Comparison of New Spirometry Measures to Diagnose COPD

BACKGROUND

COPD is diagnosed by using FEV1/FVC, which has limitations as a diagnostic test. We assessed the validity of several measures derived from the expiratory phase of the flow-volume curve obtained from spirometry to diagnose COPD: the slopes that correspond to the volume expired after the 50% and 75% of the FVC, the slope formed between the peak expiratory flow (PEF) and the FVC, and the area under the expiratory flow/volume curve.

METHODS

We conducted a cross-sectional diagnostic test study in 765 consecutive subjects referred for spirometry because of respiratory symptoms. We compared the reproducibility and accuracy of the proposed measures against post-bronchodilator FEV1/FVC < 0.70. We also evaluated the proportion of respiratory symptoms for the FEV1/FVC, FEV1 per FEV in the first 6 s (FEV6), and the PEF slope.

RESULTS

The subjects had a mean age of 65.8 y, 57% were women, and 35% had COPD. The test-retest intraclass correlation coefficient values were 0.89, 0.85, and 0.83 for FEV1/FVC, FEV1/FEV6, and the PEF slope, respectively. The area under the curve values were 0.93 (expiratory flow/volume), 0.96 (potential expiratory flow/volume), 0.97 (potential expiratory flow/volume at 75% of FVC), and 0.82 (potential expiratory flow/volume at 50% of FVC). The area under the receiver operating characteristic curve was 0.99 for FEV1/FEV6, 0.99 for the slope at 50% of the FVC, and 0.98 for the PEF slope.

CONCLUSIONS

The FEV1/FEV6, PEF slope, and 50% FVC slopes had similar diagnostic performances compared with FEV1/FVC.

Prevalence of abnormal spirometry in individuals with a smoking history and no known obstructive lung disease

INTRODUCTION

Recent evidence suggests a high prevalence of undiagnosed chronic obstructive pulmonary disease (COPD). These individuals are at risk of exacerbations and delayed treatment. We analyzed an at-risk population for the prevalence of abnormal spirometry to provide clarity into who should undergo early spirometry.

METHODS

We analyzed data from the COPDGene study. Participants with ≥10 pack-years of smoking were included. Individuals with self-reported or physician-diagnosed COPD, asthma, chronic bronchitis, emphysema and/or were on inhalers were excluded. Parsimonious multivariable logistic regression models identified factors associated with abnormal spirometry, defined as either airflow obstruction (AFO) or preserved ratio impaired spirometry. Variables were selected for the final model using a stepwise backward variable elimination process which minimized Akaike information criterion (AIC). Similarly, during the 5-year follow-up period, we assessed factors associated with incident diagnosis of COPD.

RESULTS

Of 5055 individuals, 1064 (21%) had undiagnosed AFO. Age, pack-years, current smoking and a history of acute bronchitis were associated with AFO while body mass index, female sex, and Black race were inversely associated. Among 2800 participants with 5-year follow-up, 532 (19%) had an incident diagnosis of COPD. Associated risk factors included mMRC ≥2, chronic productive cough, respiratory exacerbations during the follow-up period, and abnormal spirometry. Age was inversely associated.

CONCLUSIONS

The prevalence of undiagnosed COPD is high in at-risk populations. We found multiple factors associated with undiagnosed COPD and incident diagnosis of COPD at follow up. These results can be used to identify those at risk for undiagnosed COPD to facilitate earlier diagnosis and treatment.

Differences in clinical significance of bronchodilator responses measured by forced expiratory volume in 1 second and forced vital capacity

BACKGROUND

The clinical implication of bronchodilator response (BDR) is not fully understood. However, BDR is frequently present in patients with chronic obstructive pulmonary disease (COPD). We identified the differences in clinical features regarding BDR. In addition, we divided BDR into BDR for forced expiratory volume in 1 s (FEV1) and BDR for forced vital capacity (FVC; i.e., BDR-FEV1 and BDR-FVC, respectively) and analyzed clinical significance.

METHODS

We used data from the Korea COPD Subgroup Study, a multicenter cohort study of COPD patients recruited from 54 centers in South Korea since April 2012. We analyzed differences in baseline characteristics, 1-year exacerbation rate, and 3-year FEV1 decline between BDR negative and positive patients. Moreover, we analyzed the differences in clinical features between BDR-FEV1 positive and negative patients and between BDR-FVC positive and negative patients.

RESULTS

Of the 2,181 patients enrolled in this study, 366 (16.8%) were BDR positive. BDR positive patients were more likely to be ever-smokers and to have a lower body mass index and higher symptom scores compared to BDR negative patients. Baseline FEV1 and FEV1/FVC were lower in the BDR positive compared to the BDR negative group (1.7 ± 0.6 and 1.6 ± 0.5, respectively, p < 0.01; 50.9 ± 12.1 and 46.5 ± 14.8, respectively, p < 0.01). BDR positive patients were more likely to have been diagnosed with asthma-COPD overlap and to receive inhaled corticosteroids (ICS) than BDR negative patients. BDR-FVC patients were more likely to be smokers, suffer from worse symptoms and have lower lung function than those with no BDR-FVC. BDR had no significant effect on 1-year moderate to severe or severe exacerbation rates or 3-year annual FEV1 decline. Interactive effects of ICS and BDR on the exacerbation rate were not significant in any group.

CONCLUSIONS

In this study, BDR positive patients were more likely to be ever-smokers and to have worse symptoms and lung function than BDR negative patients. BDR-FVC was associated with worse symptom control and lung function compared to BDR-FEV1. However, there were no significant differences in exacerbation rate or decline in lung function in any BDR group. In addition, the effects of ICS on exacerbations were not significant in any group.

The prevalence of bronchodilator responsiveness of the small airway (using mid-maximal expiratory flow) in COPD - a retrospective study

BACKGROUND

Bronchodilator responsiveness (BDR) using FEV₁ is often utilised to separate COPD patients from asthmatics, although it can be present in some COPD patients. With the advent of treatments with distal airway deposition, BDR in the small airways (SA) may be of value in the management of COPD. We aimed to identify the prevalence of BDR in the SA, utilizing maximal mid-expiratory flow (MMEF) as a measure of SA. We further evaluated the prevalence of BDR in MMEF with and without BDR in FEV₁ and its association with baseline demographics, including conventional airflow obstruction severity and smoking history.

METHODS

Lung function data of ever-smoking COPD patients were retrospectively analysed. BDR was evaluated 20 min after administering 2.5 mg of salbutamol via jet nebulizer. Increase in percent change of ≥ 12% and absolute change of ≥ 200 ml was used to define a BDR in FEV₁, whereas an increase percent change of MMEF ≥ 30% was used to define a BDR in MMEF. Patients were classified as one of three groups according to BDR levels: group 1 (BDR in MMEF and FEV₁), group 2 (BDR in MMEF alone) and group 3 (no BDR in either measure).

RESULT

BDR in MMEF was present in 59.2% of the patients. Of note, BDR in MMEF was present in all patients with BDR in FEV₁ (group 1) but also in 37.9% of the patients without BDR in FEV₁ (group 2). Patients in group 1 were younger than in groups 2 and 3. BMI was higher in group 1 than in group 3. Baseline FEV₁% predicted and FVC % predicted were also higher in groups 1 and 2 than in group 3.

CONCLUSION

BDR in the SA (evaluated by MMEF) is common in COPD, and it is also feature seen in all patients with BDR in FEV₁. Even in the absence of BDR in FEV₁, BDR in MMEF is detected in some patients with COPD, potentially identifying a subgroup of patients who may benefit from different treatment strategies.

Differences in Pulmonary Function Improvement after Once-Daily LABA/LAMA Fixed-Dose Combinations in Patients with COPD

This real-world study evaluated the efficacy of once-daily long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA) fixed-dose combinations (FDCs) for improving lung function in patients with chronic obstructive pulmonary disease (COPD). Patients with COPD who were treated with once-daily LABA/LAMA FDCs for 12 months were included. We evaluated their lung function improvement after 12 months of treatment with different LABA/LAMA FDCs. A total of 198 patients with COPD who were treated with once-daily LABA/LAMA FDCs were analyzed. A total of 114 patients were treated with umeclidinium/vilanterol (UMEC/VIL); 34 patients were treated with indacaterol/glycopyrronium (IND/GLY); and 50 patients were treated with tiotropium/olodaterol (TIO/OLO). The forced expiratory volume in 1 s (FEV1) was significantly increased in the patients treated with all three once-daily FDCs (55.2% to 60.9%, p = 0.012 for UMEC/VIL, 58.2% to 63.6%, p = 0.023 for IND/GLY, and 54.1% to 57.7%, p = 0.009 for TIO/OLO). The treatment of COPD patients with TIO/OLO resulted in a significant improvement in both forced vital capacity (FVC%) (71.7% to 77.9%, p = 0.009) and residual volume (RV%) (180.1% to 152.5%, p < 0.01) compared with those treated with UMEC/VIL (FVC%: 75.1% to 81.5%, p < 0.001; RV%:173.8% to 165.2%, p = 0.231) or IND/GLY (FVC%: 73.9% to 79.3%, p = 0.08; RV%:176.8% to 168.3%, p = 0.589). Patients treated with UMEC/VIL or TIO/OLO showed significant improvement in FVC. In addition, those receiving TIO/OLO also showed significant improvement in RV reduction.

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.

Lung Function and the Risk of Exacerbation in the β-Blockers for the Prevention of Acute Exacerbations of Chronic Obstructive Pulmonary Disease Trial

Rationale: The BLOCK COPD (β-Blockers for the Prevention of Acute Exacerbations of Chronic Obstructive Pulmonary Disease) study found that metoprolol was associated with a higher risk of severe exacerbation. Objectives: To determine the mechanism underlying these results, we compared changes in lung function over the course of the study between treatment groups and evaluated whether baseline bronchodilator response or early reduction in forced expiratory volume in 1 second (FEV1) or forced vital capacity (FVC) was associated with exacerbation risk. Methods: We compared changes in lung function (FEV1 and FVC) over the treatment period between treatment groups using linear mixed-effect models. Cox proportional hazards models were used to evaluate the association between baseline bronchodilator responsiveness (FEV1, FVC, and combined FEV1 and FVC), early post-randomization (14 d) change in lung function, and the interaction between treatment assignment and these measures with risk of any or severe or very severe exacerbations. Negative binomial models were used to evaluate the relationship between bronchodilator responsiveness, the interaction between bronchodilator responsiveness and treatment assignment, and exacerbation rate. Results: Over the 336-day treatment period, individuals in the metoprolol group had a significantly greater decrease in logarithmic FEV1 from baseline to visit on Day 28 than individuals in the placebo group. Individuals in the metoprolol group had a significantly greater decrease in FVC from baseline to visits on Days 14 and 28, and also a significantly greater decrease in logarithmic FVC from baseline to visits on Days 42 and 112 than individuals in the placebo group. There were no associations between early lung function reduction or interactions between lung function reduction and treatment assignment and time to any or severe or very severe exacerbations. There were no interactions between treatment arm and baseline bronchodilator responsiveness measures on risk or rate of exacerbations. However, those with baseline FVC bronchodilator responsiveness had a higher rate of severe or very severe exacerbations (adjusted rate ratio, 1.62; 95% confidence interval, 1.04-2.48). Conclusions: Metoprolol was associated with reduced lung function during the early part of the treatment period, but these effects were modest and did not persist. Early lung function reduction and baseline bronchodilator responsiveness did not interact with the treatment arm to predict exacerbations; however, baseline FVC bronchodilator responsiveness was associated with a 60% higher rate of severe or very severe exacerbations. Clinical trial registered with www.clinicaltrials.gov (NCT02587351).

Lung Radiomics Features Selection for COPD Stage Classification Based on Auto-Metric Graph Neural Network

Chronic obstructive pulmonary disease (COPD) is a preventable, treatable, progressive chronic disease characterized by persistent airflow limitation. Patients with COPD deserve special consideration regarding treatment in this fragile population for preclinical health management. Therefore, this paper proposes a novel lung radiomics combination vector generated by a generalized linear model (GLM) and Lasso algorithm for COPD stage classification based on an auto-metric graph neural network (AMGNN) with a meta-learning strategy. Firstly, the parenchyma images were segmented from chest high-resolution computed tomography (HRCT) images by ResU-Net. Second, lung radiomics features are extracted from the parenchyma images by PyRadiomics. Third, a novel lung radiomics combination vector (3 + 106) is constructed by the GLM and Lasso algorithm for determining the radiomics risk factors (K = 3) and radiomics node features (d = 106). Last, the COPD stage is classified based on the AMGNN. The results show that compared with the convolutional neural networks and machine learning models, the AMGNN based on constructed novel lung radiomics combination vector performs best, achieving an accuracy of 0.943, precision of 0.946, recall of 0.943, F1-score of 0.943, and ACU of 0.984. Furthermore, it is found that our method is effective for COPD stage classification.

Lung Microbiota and Metabolites Collectively Associate with Clinical Outcomes in Milder Stage Chronic Obstructive Pulmonary Disease

Rationale: Chronic obstructive pulmonary disease (COPD) is variable in its development. Lung microbiota and metabolites collectively may impact COPD pathophysiology, but relationships to clinical outcomes in milder disease are unclear. Objectives: Identify components of the lung microbiome and metabolome collectively associated with clinical markers in milder stage COPD. Methods: We analyzed paired microbiome and metabolomic data previously characterized from bronchoalveolar lavage fluid in 137 participants in the SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study), or (GOLD [Global Initiative for Chronic Obstructive Lung Disease Stage 0-2). Datasets used included 1) bacterial 16S rRNA gene sequencing; 2) untargeted metabolomics of the hydrophobic fraction, largely comprising lipids; and 3) targeted metabolomics for a panel of hydrophilic compounds previously implicated in mucoinflammation. We applied an integrative approach to select features and model 14 individual clinical variables representative of known associations with COPD trajectory (lung function, symptoms, and exacerbations). Measurements and Main Results: The majority of clinical measures associated with the lung microbiome and metabolome collectively in overall models (classification accuracies, >50%, P < 0.05 vs. chance). Lower lung function, COPD diagnosis, and greater symptoms associated positively with Streptococcus, Neisseria, and Veillonella, together with compounds from several classes (glycosphingolipids, glycerophospholipids, polyamines and xanthine, an adenosine metabolite). In contrast, several Prevotella members, together with adenosine, 5'-methylthioadenosine, sialic acid, tyrosine, and glutathione, associated with better lung function, absence of COPD, or less symptoms. Significant correlations were observed between specific metabolites and bacteria (Padj < 0.05). Conclusions: Components of the lung microbiome and metabolome in combination relate to outcome measures in milder COPD, highlighting their potential collaborative roles in disease pathogenesis.

Significant Spirometric Transitions and Preserved Ratio Impaired Spirometry Among Ever Smokers

BACKGROUND

Emerging data from longitudinal studies suggest that preserved ratio impaired spirometry (PRISm), defined by proportionate reductions in FEV₁ and FVC, is a heterogeneous population with frequent transitions to other lung function categories relative to individuals with normal and obstructive spirometry. Controversy regarding the clinical significance of these transitions exists (eg, whether transitions merely reflect measurement variability or noise).

RESEARCH QUESTION

Are individuals with PRISm enriched for transitions associated with substantial changes in lung function?

STUDY DESIGN AND METHODS

Current and former smokers enrolled in the Genetic Epidemiology of COPD (COPDGene) study with spirometry available in phases 1 through 3 (enrollment, 5-year follow-up, and 10-year follow-up) were analyzed. Postbronchodilator lung function categories were as follows: PRISm (FEV₁ < 80% predicted with FEV₁/FVC ratio ≥ 0.7), Global Initiative for Chronic Obstructive Lung Disease grade 0 (FEV₁ ≥ 80% predicted and FEV₁/FVC ≥ 0.7), and obstruction (FEV₁/FVC < 0.7). Significant transition status was affirmative if a subject belonged to two or more spirometric categories and had > 10% change in FEV₁ % predicted and/or FVC % predicted between consecutive visits. Ever-PRISm was present if a subject had PRISm at any visit. Logistic regression examined the association between significant transitions and ever-PRISm status, adjusted for age, sex, race, FEV₁ % predicted, current smoking, pack-years, BMI, and ever-positive bronchodilator response.

RESULTS

Among subjects with complete data (N = 1,775) over 10.1 ± 0.4 years of follow-up, the prevalence of PRISm remained consistent (10.4%-11.3%) between phases 1 through 3, but nearly one-half of subjects with PRISm transitioned into or out of PRISm at each visit. Among all subjects, 19.7% had a significant transition; ever-PRISm was a significant predictor of significant transitions (unadjusted OR, 10.3; 95% CI, 7.9-13.5; adjusted OR, 14.9; 95% CI, 10.9-20.7). Results were similar with additional adjustment for radiographic emphysema and gas trapping, when lower limit of normal criteria were used to define lung function categories, and when FEV₁ alone (regardless of change in FVC % predicted) was used to define significant transitions.

INTERPRETATION

PRISm is an unstable group, with frequent significant transitions to both obstruction and normal spirometry over time.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT000608764; URL: www.

CLINICALTRIALS

gov.

Comparison of Clinical Characteristics and Short-Term Prognoses Within Hospitalized Chronic Obstructive Pulmonary Disease Patients Comorbid With Asthma, Bronchiectasis, and Their Overlaps: Findings From the ACURE Registry

Introduction

Real-world evidence and comparison among commonly seen chronic obstructive pulmonary disease (COPD) phenotypes, i.e., asthma–COPD overlap (ACO), bronchiectasis–COPD overlap (BCO), and their coexistence (ABCO) have not been fully depicted, especially in Chinese patients.

Methods

Data were retrieved from an ongoing nationwide registry in hospitalized patients due to acute exacerbation of COPD in China (ACURE).

Results

Of the eligible 4,813 patients with COPD, 338 (7.02%), 492 (10.22%), and 63 (1.31%) were identified as ACO, BCO, and ABCO phenotypes, respectively. Relatively, the ABCO phenotype had a younger age with a median of 62.99 years [interquartile range (IQR): 55.93–69.48] and the COPD phenotype had an older age with a median of 70.15 years (IQR: 64.37–76.82). The BCO and COPD phenotypes were similar in body mass index with a median of 21.79 kg/m² (IQR: 19.47–23.97) and 21.79 kg/m² (IQR: 19.49–24.22), respectively. The COPD phenotype had more male gender (79.90%) and smokers (71.12%) with a longer history of smoking (median: 32.45 years, IQR: 0.00–43.91). The ACO and ABCO phenotypes suffered more prior allergic episodes with a proportion of 18.05 and 19.05%, respectively. The ACO phenotype exhibited a higher level of eosinophil and better lung reversibility. Moreover, the four phenotypes showed no significant difference neither in all-cause mortality, intensive care unit admission, length of hospital stay, and COPD Assessment Test score change during the index hospitalization, and nor in the day 30 outcomes, i.e., all-cause mortality, recurrence of exacerbation, all-cause, and exacerbation-related readmission.

Conclusions

The ACO, BCO, ABCO, and COPD phenotypes exhibited distinct clinical features but had no varied short-term prognoses. Further validation in a larger sample is warranted.

Lung proteomic biomarkers associated with chronic obstructive pulmonary disease

Identifying protein biomarkers for chronic obstructive pulmonary disease (COPD) has been challenging. Most previous studies have used individual proteins or preselected protein panels measured in blood samples. Mass spectrometry proteomic studies of lung tissue have been based on small sample sizes. We used mass spectrometry proteomic approaches to discover protein biomarkers from 150 lung tissue samples representing COPD cases and controls. Top COPD-associated proteins were identified based on multiple linear regression analysis with false discovery rate (FDR) < 0.05. Correlations between pairs of COPD-associated proteins were examined. Machine learning models were also evaluated to identify potential combinations of protein biomarkers related to COPD. We identified 4,407 proteins passing quality controls. Twenty-five proteins were significantly associated with COPD at FDR < 0.05, including interleukin 33, ferritin (light chain and heavy chain), and two proteins related to caveolae (CAV1 and CAVIN1). Multiple previously reported plasma protein biomarkers for COPD were not significantly associated with proteomic analysis of COPD in lung tissue, although RAGE was borderline significant. Eleven pairs of top significant proteins were highly correlated (r > 0.8), including several strongly correlated with RAGE (EHD2 and CAVIN1). Machine learning models using Random Forests with the top 5% of protein biomarkers demonstrated reasonable accuracy (0.707) and area under the curve (0.714) for COPD prediction. Mass spectrometry-based proteomic analysis of lung tissue is a promising approach for the identification of biomarkers for COPD.

Omalizumab in Asthma with Fixed Airway Obstruction: Post Hoc Analysis of EXTRA

BACKGROUND

Although asthma is typically characterized by bronchodilator responsiveness (BDR), fixed airflow obstruction (FAO) occurs in ∼50% of patients with severe asthma.

OBJECTIVE

Do FAO/BDR associate with efficacy of omalizumab, a monoclonal antibody that targets IgE?

METHODS

In EXTRA, patients aged 12-75 years with inadequately controlled severe allergic asthma despite high-dose inhaled corticosteroids plus long-acting β₂-agonists were randomized to omalizumab (n = 427) or placebo (n = 423) for 48 weeks of treatment. In this post hoc analysis, high/low BDR were defined as ≥12%/<12% increases in baseline forced expiratory volume in 1 second (FEV₁) after bronchodilator administration, respectively. FAO presence (+)/absence (-) were defined as baseline postbronchodilator FEV₁/forced vital capacity <70%/≥70%, respectively. Poisson regression/analysis of covariance models were used to estimate exacerbation relative rate reductions (RRRs)/least-squares mean changes in FEV₁, respectively.

RESULTS

In patients with high BDR, omalizumab reduced exacerbations more than placebo over the 48-week treatment period regardless of FAO status (RRR [95% confidence interval (CI)]: FAO+, 59.8% [17.7-80.4%]; FAO-, 44.3% [16.6-62.8%]). Omalizumab improved FEV₁ compared with placebo in the FAO-, high BDR subgroup (FEV₁ change from baseline [95% CI] for omalizumab vs placebo, 0.065 L [-0.071 to 0.201 L] to 0.236 L [0.112-0.359 L]) across 48 weeks. This was not observed in patients with low BDR, irrespective of FAO.

CONCLUSION

Omalizumab was more efficacious than placebo at reducing exacerbations in patients with high, but not low, BDR, regardless of the presence of FAO. Lung function improvement primarily occurred in FAO-, high BDR patients, suggesting that asthma with low BDR may represent a difficult-to-treat phenotype.

Discordant Quantitative and Visual CT Assessments in the Diagnosis of Emphysema

Purpose

Visual assessment of computed tomography (CT) of the lung is routinely employed in the diagnosis of emphysema. Quantitative CT (QCT) can complement visual CT but must be well validated. QCT emphysema is defined as ≥5% of lung volume occupied by low attenuation areas ≤-950 Hounsfield units (LAA-950). Discordant visual and QCT assessments are not uncommon. We examined the association between visual and quantitative chest CT evaluation within a large cohort of subjects to identify variables that may explain discordant visual and QCT findings.

Materials and Methods

Volumetric inspiratory CT scans of 1221 subjects enrolled in phase 1 of the COPDGene study conducted at the University of Iowa were reviewed. Participants included never smokers, smokers with normal spirometry, preserved ratio impaired spirometry, and Global Initiative for Obstructive Lung Disease (GOLD) stages I-IV. CT scans were quantitatively scored and visually interpreted by both the COPDGene Imaging Center and the University of Iowa radiologists. Individual-level visual assessments were compared with QCT measurements. Agreement between the two sets of radiologists was calculated using kappa statistic. We assessed variables associated with discordant results using regression methods.

Results

There was a fair agreement for the presence or absence of emphysema between our center's radiologists and QCT (61% concordance, kappa 0.22 [0.17-0.28]). Similar comparisons showed a slight agreement between the COPDGene Imaging Center and QCT (56% concordance, kappa 0.16 [0.11-0.21]), and a moderate agreement between both sets of visual assessments (80% concordance, kappa 0.60 [0.54-0.65]). Current smoking and female gender were significantly associated with QCT-negative but visually detectable emphysema.

Conclusion

The slight-to-fair agreement between visual and quantitative CT assessment of emphysema highlights the need to utilize both modalities for a comprehensive radiologic evaluation. Discordant results may be attributable to one or more factors that warrant further exploration in larger studies.

Clinical Trial Registration

ClinicalTrials.gov Identifier NCT000608764.

Diagnostic performance of lung volumes in assessment of reversibility in chronic obstructive pulmonary disease

Background

Reversibility measured by spirometry in chronic obstructive pulmonary disease (COPD) is defined as an increase in forced expiratory volume in first second (FEV1) that is both more than 12% and 200 mL above the pre-bronchodilator value in response to inhaled bronchodilators. FEV1 only may not fully reverberate the changes caused by reduction in air trapping or hyperinflation. To date, the studies that examined the effect of inhaled bronchodilators (BD) on residual volume (RV) and total lung capacity (TLC) are limited. This study was carried out to assess the differences between flow and volume responses after bronchodilator reversibility testing in patients with different COPD GOLD stages (GOLD stage I to stage IV). Spirometry and whole body plethysmography were done before and 15 min after inhalation of 400 μg salbutamol.

Results

Majority (53.3%) of cases were volume responders, 18.7% were flow responders, 20% were flow and volume responders, and 8% were non responders. Significant increase in Δ FEV1% was found in 15% of cases while 55% showed a significant increase in Δ FVC (P= < 0.001). Mean difference of Δ FVC (L) post BD was significantly increased with advancing GOLD stage (P= 0.03). A cutoff point > 20% for Δ RV% had 70% sensitivity and 60% specificity and > 12% for Δ TLC% showed 90% sensitivity and 45% specificity for prediction of clinically significant response to BD based on FEV1. A cutoff point > 18% for Δ RV% had 78% sensitivity and 29% specificity and > 14% for Δ TLC% had 50% sensitivity and 70% specificity for prediction of clinically significant response to BD based on FVC.

Conclusion

ΔFEV1 underestimates the true effect of bronchodilators with advancing GOLD stage. Measurement of lung volumes in addition to the standard spirometric indices is recommended when determining bronchodilator response in COPD patients.

Inhaled Medication Use in Smokers With Normal Spirometry

BACKGROUND

The objective of our study was to identify variables associated with inhaled medication use in smokers with normal spirometry (GOLD-0) and to examine the association of inhaled medication use with development of exacerbations and obstructive spirometry in the future.

METHODS

We performed a retrospective multivariable analysis of GOLD-0 subjects identified in data from the COPDGene study to examine factors associated with medication use. Five categories were identified: (1) no medications, (2) short-acting bronchodilator, (3) long-acting bronchodilator; long-acting muscarinic antagonists and/or long-acting β agonist, (4) inhaled corticosteroids (ICS) with or without long-acting bronchodilator, and (5) dual bronchodilator with ICS. Sensitivity analysis was performed excluding subjects with history of asthma. We also evaluated whether long-acting inhaled medication use was associated with exacerbations and obstructive spirometry at the follow-up visit 5 y after enrollment.

RESULTS

Of 4,303 GOLD-0 subjects within the analysis, 541 of them (12.6%) received inhaled medications. Of these, 259 (6%) were using long-acting inhaled medications and 282 (6.6%) were taking short-acting bronchodilator. Female sex (odds ratio [OR] 1.47, P = .003), numerous medical comorbidities, radiographic emphysema (OR 2.22, P = .02), chronic bronchitis (OR 1.77, P < .001), dyspnea (OR 2.24, P < .001), asthma history (OR 15.56, P < .001), prior exacerbation (OR 8.45, P < .001), and 6-min walk distance (OR 0.9, P < .001) were associated with medication use. Minimal changes were noted in a sensitivity analysis. Additionally, inhaled medications were associated with increased total (incidence rate ratio 2.83, P < .001) and severe respiratory exacerbations (incidence rate ratio 3.64, P < .001) and presence of obstructive spirometry (OR 2.83, P = .002) at follow-up.

CONCLUSIONS

Respiratory symptoms, history of asthma, and radiographic emphysema were associated with inhaled medication use in smokers with normal spirometry. These individuals were more likely to develop obstructive spirometry, which suggests that health care providers may be able to identify obstructive lung disease prior to meeting the current criteria for COPD.

Lung microbiota associations with clinical features of COPD in the SPIROMICS cohort

Chronic obstructive pulmonary disease (COPD) is heterogeneous in development, progression, and phenotypes. Little is known about the lung microbiome, sampled by bronchoscopy, in milder COPD and its relationships to clinical features that reflect disease heterogeneity (lung function, symptom burden, and functional impairment). Using bronchoalveolar lavage fluid collected from 181 never-smokers and ever-smokers with or without COPD (GOLD 0-2) enrolled in the SubPopulations and InteRmediate Outcome Measures In COPD Study (SPIROMICS), we find that lung bacterial composition associates with several clinical features, in particular bronchodilator responsiveness, peak expiratory flow rate, and forced expiratory flow rate between 25 and 75% of FVC (FEF_25–75). Measures of symptom burden (COPD Assessment Test) and functional impairment (six-minute walk distance) also associate with disparate lung microbiota composition. Drivers of these relationships include members of the Streptococcus, Prevotella, Veillonella, Staphylococcus, and Pseudomonas genera. Thus, lung microbiota differences may contribute to airway dysfunction and airway disease in milder COPD.

Ratio of FEV1/Slow Vital Capacity of < 0.7 Is Associated With Clinical, Functional, and Radiologic Features of Obstructive Lung Disease in Smokers With Preserved Lung Function

BACKGROUND

Mild expiratory flow limitation may not be recognized using traditional spirometric criteria based on the ratio of FEV₁/FVC.

RESEARCH QUESTION

Does slow vital capacity (SVC) instead of FVC increase the sensitivity of spirometry to identify patients with early or mild obstructive lung disease?

STUDY DESIGN AND METHODS

We included 854 current and former smokers from the Subpopulations and Intermediate Outcome Measures in COPD Study cohort with a postbronchodilator FEV₁/FVC ≥ 0.7 and FEV₁ % predicted of ≥ 80% at enrollment. We compared baseline characteristics, chest CT scan features, exacerbations, and progression to COPD (postbronchodilator FEV₁/FVC, < 0.7) during the follow-up period between 734 participants with postbronchodilator FEV₁/SVC of ≥ 0.7 and 120 with postbronchodilator FEV₁/SVC < 0.7 at the enrollment. We performed multivariate linear and logistic regression models and negative binomial and interval-censored proportion hazards regression models adjusted for demographics and smoking exposure to examine the association of FEV₁/SVC < 0.7 with those characteristics and outcomes.

RESULTS

Participants with FEV₁/SVC < 0.7 were older and had lower FEV₁ and more emphysema than those with FEV₁/SVC ≥ 0.7. In adjusted analysis, individuals with postbronchodilator FEV₁/SVC < 0.7 showed a greater percentage of emphysema by 0.45% (95% CI, 0.09%-0.82%), percentage of gas trapping by 2.52% (95% CI, 0.59%-4.44%), and percentage of functional small airways disease based on parametric response mapping by 2.78% (95% CI, 0.72%-4.83%) at baseline than those with FEV₁/SVC ≥ 0.7. During a median follow-up time of 1,500 days, an FEV₁/SVC < 0.7 was not associated with total exacerbations (incident rate ratio [IRR], 1.61; 95% CI, 0.97-2.64), but was associated with severe exacerbations (IRR, 2.60; 95% CI, 1.04-4.89). An FEV₁/SVC < 0.7 was associated with progression to COPD during a 3-year follow-up even after adjustment for demographics and smoking exposure (hazard ratio, 3.93; 95% CI, 2.71-5.72). We found similar results when we examined the association of prebronchodilator FEV₁/SVC < 0.7 or FEV₁/SVC less than the lower limit of normal with chest CT scan features and progression to COPD.

INTERPRETATION

Low FEV₁ to SVC in current and former smokers with normal spirometry results can identify individuals with CT scan features of COPD who are at risk for severe exacerbations and is associated with progression to COPD in the future.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01969344T4; URL: www.clinicaltrials.gov.

Preserved Ratio Impaired Spirometry in a Spirometry Database

BACKGROUND

Spirometry results can yield a diagnosis of normal air flow, air flow obstruction, or preserved ratio impaired spirometry (PRISm), defined as a reduced FEV₁ or FVC in the setting of preserved FEV₁/FVC. Previous studies have estimated the prevalence of PRISm to be 7-12%. Our objective was to examine the prevalence of PRISm in a spirometry database and to identify factors associated with PRISm.

METHODS

We performed a retrospective analysis of 21,870 spirometries; 1,616 were excluded because of missing data or extremes of age, height, or weight. We calculated the prevalence of PRISm in prebronchodilator and postbronchodilator pulmonary function tests. Subsequently, we calculated the prevalence of PRISm by various age, race, body mass index, and diagnosis categories, as well as by gender and smokers versus nonsmokers. Finally, in the subset of the cohort with FEV₁ < lower limit of normal, we performed a multivariable logistic regression analysis to identify factors associated with PRISm.

RESULTS

We identified 18,059 prebronchodilator spirometries, and 22.3% of these yielded a PRISm diagnosis. This prevalence remained stable in postbronchodilator spirometries (17.7%), after excluding earlier pulmonary function tests for subjects with multiple pulmonary function tests (20.7% in prebronchodilator and 24.3% in postbronchodilator), and when we limited the analysis to prebronchodilator spirometries that met American Thoracic Society criteria (20.6%). The PRISm prevalence was higher in subjects 45-60 y old (24.4%) and in males (23.7%) versus females (17.9%). The prevalence rose with body mass index and was higher for those with a referral diagnosis of restrictive lung disease (50%). PRISm prevalence was similar between races and smokers versus nonsmokers. In a multivariable analysis, higher % of predicted FEV₁ (odds ratio 1.51, 95% CI 1.42-1.60), body mass index (odds ratio 1.52, 95% CI 1.39-1.68), and restrictive lung disease (odds ratio 4.32, 95% CI 2.54-7.57) were associated with a diagnosis of PRISm. Smoking was inversely associated (odds ratio 0.55, 95% CI 0.46-0.65) with PRISm.

CONCLUSIONS

In a spirometry database at an academic medical center, the PRISm prevalence was 17-24%, which is higher than previously reported.

Characteristics Associated with Accelerated Lung Function Decline in a Primary Care Population with Chronic Obstructive Pulmonary Disease

Background

Estimates for lung function decline in chronic obstructive pulmonary disease (COPD) have differed by study setting and have not been described in a UK primary care population.

Purpose

To describe rates of FEV₁ and FVC decline in COPD and investigate characteristics associated with accelerated decline.

Patients and Methods

Current/ex-smoking COPD patients (35 years+) who had at least 2 FEV₁ or FVC measurements ≥6 months apart were included using Clinical Practice Research Datalink. Patients were followed up for a maximum of 13 years. Accelerated rate of lung function decline was defined as the fastest quartile of decline using mixed linear regression, and association with baseline characteristics was investigated using logistic regression.

Results

A total of 72,683 and 50,649 COPD patients had at least 2 FEV₁ or FVC measurements, respectively. Median rates of FEV₁ and FVC changes or decline were -18.1mL/year (IQR: -31.6 to -6.0) and -22.7mL/year (IQR: -39.9 to -6.7), respectively. Older age, high socioeconomic status, being underweight, high mMRC dyspnoea and frequent AECOPD or severe AECOPD were associated with an accelerated rate of FEV₁ and FVC decline. Current smoking, mild airflow obstruction and inhaled corticosteroid treatment were additionally associated with accelerated FEV₁ decline whilst women, sputum production and severe airflow obstruction were associated with accelerated FVC decline.

Conclusion

Rate of FEV₁ and FVC decline was similar and showed similar heterogeneity. Whilst FEV₁ and FVC shared associations with baseline characteristics, a few differences highlighted the importance of both lung function measures in COPD progression. We identified important characteristics that should be monitored for disease progression.

Chronic Obstructive Pulmonary Disease and Lung Transplantation

Lung transplantation (LTx) has been a viable option for patients with end-stage chronic obstructive pulmonary disease (COPD), with more than 20,000 procedures performed worldwide. Survival after LTx lags behind most other forms of solid-organ transplantation, with median survival for COPD recipients being a sobering 6.0 years. Given the limited supply of suitable donor organs, not all patients with end-stage COPD are candidates for LTx. We discuss appropriate criteria for accepting patients for LTx, as well as contraindications and exclusionary criteria. In the first year post-LTx, infection and graft failure are the leading causes of death. Beyond this chronic graft rejection-currently referred to as chronic lung allograft dysfunction-represents the leading cause of death at all time points, with infection and over time malignancy also limiting survival. Referral of COPD patients to a lung transplant center should be considered in the presence of progressing disease despite maximal medical therapy. As a rule of thumb, a forced expiratory volume in 1 second < 25% predicted in the absence of exacerbation, hypoxia (PaO₂ < 60 mm Hg/8 kPa), and/or hypercapnia (PaCO₂ > 50 mm Hg/6.6 kPa) and satisfactory general clinical condition should be considered the basic prerequisites for timely referral. We also discuss salient issues post-LTx and factors that impact posttransplant survival and morbidity such as infections, malignancy, renal insufficiency, and complications associated with long-term immunosuppression.

Re-evaluation of the Uplift Clinical Trial Using Age-Appropriate Spirometric Criteria

BACKGROUND

The clinical trial of tiotropium in COPD, UPLIFT, enrolled adults with a mean age of 65 years and moderate-to-severe airflow obstruction, based on criteria from the Global Initiative for Chronic Obstructive Lung Disease (GOLD). For the UPLIFT cohort, however, GOLD-based criteria are not age-appropriate.

RESEARCH QUESTION

Will the use of more age-appropriate criteria for airflow obstruction from the Global Lung Function Initiative (GLI) modify the spirometric classification of the UPLIFT cohort and, in turn, the mortality effect of tiotropium in COPD?

STUDY DESIGN AND METHODS

Baseline spirometric classifications were first cross-tabulated by GLI- and GOLD-based criteria. Next, in GLI- and GOLD-based airflow obstruction, modified intention-to-treat analyses evaluated differences in time to death over 4 years, comparing tiotropium vs placebo. Because treatment response may differ by COPD severity, the mortality effect also was evaluated within stratum defined by GLI- and GOLD-based moderate and severe airflow obstruction.

RESULTS

Of 5,898 participants with GOLD-based airflow-obstruction, staged as moderate in 2,739 (46.4%) and severe in 3,156 (53.5%), GLI-based criteria established airflow obstruction in 5,750 (97.5%), staged as moderate in 795 (13.5%) and severe in 4,947 (83.9%). Relative to placebo, tiotropium yielded statistically nonsignificant adjusted hazard ratios (adjHRs) (95% CI) for death of 0.91 (0.80-1.04) and 0.91 (0.79-1.03) in GLI- and GOLD-based airflow obstruction, respectively. However, statistically significant effect modification was observed, but only in GLI-based moderate and severe airflow-obstruction, with tiotropium yielding adjHRs for death of 0.53 (0.34-0.81) and 0.99 (0.86-1.13), respectively. The P value for interaction was .007.

INTERPRETATION

Mortality reduction by tiotropium was only statistically significant in GLI-based moderate airflow-obstruction, a group that was underrepresented in UPLIFT because of severity misclassification by the original GOLD-based enrollment criteria.

Area Under the Expiratory Flow-Volume Curve (AEX): Assessing Bronchodilator Responsiveness

Background

Area under expiratory flow–volume curve (AEX) is a useful spirometric tool in stratifying respiratory impairment. The AEX approximations based on isovolumic flows can be used with reasonable accuracy when AEX is unavailable. We assessed here pre- to post-bronchodilator (BD) variability of AEX₄ as a functional assessment tool for lung disorders.

Methods

The BD response was assessed in 4330 subjects by changes in FEV₁, FVC, and AEX₄, which were derived from FVC, peak expiratory flow, and forced expiratory flow at 25%, 50%, and 75% FVC. Newly proposed BD response categories (negative, minimal, mild, moderate and marked) have been investigated in addition to standard criteria.

Results

Using standard BD criteria, 24% of subjects had a positive response. Using the new BD response categories, only 23% of subjects had a negative response; 45% minimal, 18% mild, 9% moderate, and 5% had a marked BD response. Mean percent change of the square root AEX₄ was 0.3% and 14.3% in the standard BD-negative and BD-positive response groups, respectively. In the new BD response categories of negative, minimal, mild, moderate, and marked, mean percent change of square root AEX₄ was − 8.2%, 2.9%, 9.2%, 15.0%, and 24.8%, respectively.

Conclusions

Mean pre- to post-BD variability of AEX₄ was < 6% and stratified well between newly proposed categories of BD response (negative, minimal, mild, moderate and marked). We suggest that AEX₄ (AEX) could become a useful measurement for stratifying dysfunction in obstructive lung disease and invite further investigation into indications for using bronchodilator agents or disease-modifying, anti-inflammatory therapies.

Low FVC/TLC in Preserved Ratio Impaired Spirometry (PRISm) is associated with features of and progression to obstructive lung disease

One quarter of individuals with Preserved Ratio Impaired Spirometry (PRISm) will develop airflow obstruction, but there are no established methods to identify these individuals. We examined the utility of FVC/TLC in identifying features of obstructive lung disease. The ratio of post-bronchodilator FVC and TLC_CT from chest CT (FVC/TLC_CT) among current and former smokers with PRISm (FEV₁/FVC ≥ 0.7 and FEV1 < 80%) in COPDGene was used to stratify subjects into quartiles: very high, high, low, and very low. We examined the associations between FVC/TLC_CT quartiles and (1) baseline characteristics, (2) respiratory exacerbations, (3) progression to COPD at 5 years, and (4) all-cause mortality. Among participants with PRISm at baseline (n = 1,131), the very low FVC/TLC_CT quartile was associated with increased gas trapping and emphysema, and higher rates of progression to COPD at 5 years (36% versus 17%; p < 0.001) relative to the very high quartile. The very low FVC/TLC_CT quartile was associated with increased total (IRR = 1.65; 95% CI [1.07–2.54]) and severe (IRR = 2.24; 95% CI [1.29–3.89]) respiratory exacerbations. Mortality was lower in the very high FVC/TLC_CT quartile relative to the other quartiles combined. Reduced FVC/TLC_CT ratio in PRISm is associated with increased symptoms, radiographic emphysema and gas trapping, exacerbations, and progression to COPD.

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.

Chronic Obstructive Pulmonary Disease and the Optimal Timing of Lung Transplantation

Chronic obstructive pulmonary disease (COPD) accounts for the largest proportion of respiratory deaths worldwide and was historically the leading indication for lung transplantation. The success of lung transplantation procedures is measured as survival benefit, calculated as survival with transplantation minus predicted survival without transplantation. In chronic obstructive pulmonary disease, it is difficult to show a clear and consistent survival benefit. Increasing knowledge of the risk factors, phenotypical heterogeneity, systemic manifestations, and their management helps improve our ability to select candidates and list those that will benefit the most from the procedure.