Post-bronchodilator Spirometry Research Articles

A protocol for a Japanese prospective cohort evaluating the features of patients with uncontrolled asthma achieving clinical remission: J-CIRCLE

BackgroundIncreasing expectations that biologics can be used as disease-modifying agents have introduced the concept of clinical remission (CR) in managements of severe asthma. Given the clinical relevance of computed tomography (CT) and blood biomarkers, we hypothesized that further refinement of CR criteria as well as incorporation of CT and blood biomarkers as indicators for structural and biological remission (SR, BR) would enable predicting long-term disease stability in patients with severe asthma treated with biologics. MethodsThis Japanese multicenter prospective observational cohort will enroll patients with severe asthma who will start a new biologic (including a change from another biologic). The enrolled patients will be longitudinally followed up for 3 years. At enrollment, patients will undergo postbronchodilator spirometry, blood tests, fractional exhaled nitric oxide, chest and sinus CT, and patient-reported outcome questionnaires. Follow-up examinations will be performed at 1, 3, 6, 12, 24, and 36 months. The rates of CR resulting from different criteria after 1 year of treatment with biologics will be compared, and factors associated with long-term disease stability after 3 years of biologic treatments will be identified. DiscussionThis multicenter study in Japan will provide data that will help establish more appropriate criteria for CR, structural remission, and biological remission to predict long-term disease stability in patients with severe asthma who receive biologic therapy. Ethics and disseminationThe study was approved by the Ethics Committee of Kyoto University (No. R4419, approval date June 11th, 2024). Trial registrationThe University Hospital Medical Information Network (UMIN000053771).

A Study on the Correlation Between Sarcopenia and Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease that affects the entire body. Sarcopenia, one of the adverse manifestations of the whole body, can lead to a variety of adverse outcomes. The worldwide studies have shown that sarcopenia was associated with COPD. This article aims to further enrich this research direction by focusing on the relationship between sarcopenia and COPD in Chinese inpatients. The subjects of this study were patients hospitalized in the Department of Respiratory and Critical Care Medicine of Rongchang People's Hospital of Chongqing from July 2022 to May 2024. After bioelectrical impedance analysis (BIA), test of 6 m walking speed, and tests for upper grip strength were accomplished, the sarcopenia can be diagnosed. According to the presence of chronic airflow limitation, which assessed by post-bronchodilator spirometry, we diagnosed COPD. COPD and sarcopenia as two variables, simple correlation analysis was adopted for them. The subjects were classified into sarcopenia group and non-sarcopenia group. And then, the correlation between sarcopenia and COPD was assessed with binary logistic regression analysis. Finally we get the results. Spearman's correlation coefficient for sarcopenia and COPD was 0.166 (p<0.05). While, COPD was not an independent risk factor to sarcopenia in the binary logistic regression analysis. Therefore, this study draws conclusions that COPD and sarcopenia is associated, but not linked independently.

Optimal spirometry thresholds for the prediction of chronic airflow obstruction: a multinational longitudinal study

IntroductionChronic airflow obstruction is key for COPD diagnosis but strategies for its early detection are limited. We aimed to define the optimal z-score thresholds for spirometry parameters to discriminate chronic airflow obstruction incidence.MethodsThe Burden of Obstructive Lung Disease study is a multinational cohort study. Information on respiratory symptoms was collected and pre- and post-bronchodilator spirometry was performed at baseline. Eighteen study sites were followed up with repeat measurements after a median of 8.4 years. We converted lung function measurements into z-scores using the Third National Health and Nutrition Survey reference equations. We used the Youden index to calculate the optimal z-score thresholds for discriminating chronic airflow obstruction incidence. We further examined differences by smoking status.ResultsWe analysed data from 3057 adults (57% females, mean age: 51 years at baseline). Spirometry parameters were good at discriminating chronic airflow obstruction incidence (AUC 0.80–0.84), while respiratory symptoms performed poorly. The optimal z-score threshold was identified for pre-bronchodilator FEV1/FVC <-1.336, equivalent to the 9th percentile (sensitivity: 78%, specificity: 72%). All z-score thresholds associated with a lower post-bronchodilator FEV1/FVC and greater odds of chronic airflow obstruction at follow-up. The risk of chronic airflow obstruction was slightly greater for current smokers and, to some extent, never smokers with a pre-bronchodilator FEV1/FVC less than the 9th/10th percentiles at baseline, particularly among males.ConclusionsSpirometry is better than respiratory symptoms at predicting chronic airflow obstruction incidence. A pre-bronchodilator FEV1/FVC <9th/10th percentiles, particularly among current smokers, could suggest early airflow obstruction or pre-COPD.

Assessing the prevalence and impact of preserved ratio impaired spirometry in low-income and middle-income countries: a post-hoc cross-sectional analysis

More than 90% of the morbidity and mortality from chronic respiratory disease occurs in low-income and middle-income countries (LMICs), with substantial economic impact. Preserved ratio impaired spirometry (PRISm) is a prevalent lung function abnormality associated with increased mortality in high-income countries. We aimed to conduct a post-hoc analysis of a cross-sectional study to assess the prevalence of, the risk factors for, and the impact of PRISm in three diverse LMIC settings. We recruited a random, age-stratified and sex-stratified sample of the population in semi-urban Bhaktapur, Nepal; urban Lima, Peru; and rural Nakaseke, Uganda. Quality-assured post-bronchodilator spirometry was performed to American Thoracic Society standards and PRISm was defined as a forced expiratory volume in one second (FEV1) of less than 80% predicted with a FEV1/forced vital capacity ratio of 0·70 or more. We used t tests and χ2 analyses to assess the relationships between demographic, biometric, and comorbidity variables with PRISm. Multivariable logistic models with random intercept by site were used to estimate odds ratios (ORs) with 95% CIs. 10 664 participants were included in the analysis, with a mean (SD) age of 56·3 (11·7) years and an equal distribution by sex. The prevalence of PRISm was 2·5% in Peru, 9·1% in Nepal, and 16·0% in Uganda. In multivariable analysis, younger age (OR for each decile of age 0·87, 95% CI 0·82-0·92) and being female (1·37, 1·18-1·58) were associated with increased odds of having PRISm. Biomass exposure was not consistently associated with PRISm across sites. Individuals with PRISm had impairment in respiratory-related quality of life as measured by the St George's Respiratory Questionnaire (OR by decile 1·18, 95% CI 1·10-1·25). The prevalence of PRISm is heterogeneous across LMIC settings and associated with age, female sex, and biomass exposure, a common exposure in LMICs. A diagnosis of PRISm was associated with worse health status when compared with those with normal lung function. Health systems in LMICs should focus on all spirometric abnormalities as opposed to obstruction alone, given the disease burden, reduced quality of life, and size of the undiagnosed population at risk. Medical Research Council.

Association between biomass exposure and COPD occurrence in Fez, Morocco: results from the BOLD study

ObjectiveTo investigate the association between biomass exposure and chronic obstructive pulmonary disease (COPD) in a representative sample of adults from the Moroccan populationMethodsA cross-sectional study was conducted in Fez as...

Association between impaired diffusion capacity and small airway dysfunction: a cross-sectional study

BackgroundSmall airway dysfunction (SAD) and impaired diffusion capacity of the lungs for carbon monoxide (DLCO) are positively associated with a worse prognosis. Individuals with both dysfunctions have been identified in clinical, and it is unknown whether they had worse health status or need management. We conducted this study to explore the association between SAD and impaired DLCO, and the difference between the groups with two dysfunctions, with either one dysfunction, and with no dysfunction.MethodsThis study involved subjects partly from those who had returned for the third-year follow-up (up to December 2022) of the ECOPD Study and those who newly participated. We assessed the diffusion capacity, questionnaire, exacerbations, spirometry, impulse oscillometry (IOS), and computed tomography (CT). Impaired DLCOwas defined as DLCO%predicted <80%. Spirometry-defined SAD was defined using MMEF %predicted, FEF50%predicted, and FEF75%predicted; at least two of the three being <65% using post-bronchodilator spirometry. IOS-defined SAD was defined as R5-R20 >0.07 kPa·L−1·s−1. CT-defined SAD was defined by LAA−856% comprising ≥15% of the total lung volume. Covariate analyses and logistic regression were performed to assess the association between impaired DLCOand SAD.ResultsThis study involved 581 subjects. The occurrence of both spirometry- and CT-defined SAD was significantly higher in subjects with impaired than normal DLCOSubjects with two dysfunctions were associated with worse preceding-year exacerbations than controls.ConclusionsImpaired diffusion capacity is positively associated with SAD. Subjects with impaired diffusion capacity and SAD may have a worse health status and need additional management.

Restrictive Spirometric Pattern and Preserved Ratio Impaired Spirometry in a Population Aged 50-64 Years.

Rationale: Knowledge regarding the prevalence and shared and unique characteristics of the restrictive spirometric pattern (RSP) and preserved ratio impaired spirometry (PRISm) is lacking for a general population investigated with post-bronchodilator spirometry and computed tomography of the lungs. Objectives: To investigate shared and unique features for RSP and PRISm. Methods: In the Swedish CArdioPulmonary bioImage Study (SCAPIS), a general population sample of 28,555 people aged 50-64 years (including 14,558 never-smokers) was assessed. The participants answered a questionnaire and underwent computed tomography of the lungs, post-bronchodilator spirometry, and coronary artery calcification score. Odds ratios with 95% confidence intervals (CIs) were calculated using adjusted logistic regression. RSP was defined as forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ≥0.70 and FVC <80%. PRISm was defined as FEV1/FVC ≥0.70 and FEV1 <80%. A local reference equation was applied. Results: The prevalence of RSP and PRISm were 5.1% (95% CI, 4.9-5.4) and 5.1% (95% CI, 4.8-5.3), respectively, with similar values seen in never-smokers. For RSP and PRISm, shared features were current smoking, dyspnea, chronic bronchitis, rheumatic disease, diabetes, ischemic heart disease, bronchial wall thickening, interstitial lung abnormalities, and bronchiectasis. Emphysema was uniquely linked to PRISm (odds ratio, 1.69; 95% CI, 1.36-2.10) versus 1.10 (95% CI, 0.84-1.43) for RSP. Coronary artery calcification score ≥300 was related to PRISm, but not among never-smokers. Conclusions: PRISm and RSP have respiratory, cardiovascular, and metabolic conditions as shared features. Emphysema is only associated with PRISm. Coronary atherosclerosis may be associated with PRISm. Our results indicate that RSP and PRISm may share more features than not.

Chronic respiratory disease observatory for Africa (CHEST-Africa): study protocol for the prevalence, determinants and economic impacts of asthma and COPD in Africa

IntroductionContemporary data on the burden of chronic respiratory diseases in sub-Saharan Africa is limited. More so, their economic burden is not well described. This study aims to establish a chronic...

Assessing post-COVID-19 respiratory dynamics: a comprehensive analysis of pulmonary function, bronchial hyperresponsiveness and bronchodilator response.

Coronavirus disease 2019 (COVID-19) has a considerable impact on the global healthcare system. Individuals who have recovered from COVID often experience chronic respiratory symptoms that affect their daily lives. This study aimed to assess respiratory dynamics such as airway hyperresponsiveness (AHR) and bronchodilator response in post-COVID patients. This study included 282 adults with respiratory symptoms who underwent provocation tests. The demographic details, clinical symptoms and medical histories were recorded. Baseline spirometry, methacholine challenge tests (MCT) and post-bronchodilator spirometry were performed. Patients were divided into the following four groups: Group 1: non-COVID-19 and negative MCT; Group 2: post-COVID-19 and negative MCT; Group 3: non-COVID-19 and positive MCT; and Group 4: post-COVID-19 and positive MCT. Most post-COVID-19 patients (43.7%) experienced AHR, and wheezing was more common. Patients in Group 4 exhibited increased intensities of dyspnoea, cough and wheezing with the lowest pulmonary function test (PFT) parameters at baseline. Moreover, significant decreases in PFT parameters after the MCT were observed in these patients. Although the prevalence of a low forced expiratory volume in 1 s to forced vital capacity ratio (<70%) was initially 2% in Group 4, it increased to 29% after MCT. No significant differences in allergic history or underlying diseases were observed between the groups. These findings provide comprehensive insights into the AHR and respiratory symptoms of post-COVID-19 individuals, highlighting the characteristics and potential exacerbations in patients with positive MCT results. This emphasises the need of MCT to address respiratory dynamics in post-COVID-19 individuals.

Prevalence of alpha-1 antitrypsin deficiency in patients with acute exacerbation of chronic obstructive pulmonary disease: Insights from a prospective study.

Alpha-1 antitrypsin (AAT) deficiency is a genetic risk factor for chronic obstructive pulmonary disease (COPD) but prevalence data in acutely exacerbated Indian patients is limited. This study determined AAT deficiency rates and correlations with inflammation and lung function among hospitalized patients with COPD. A total of 106 patients hospitalized for acute COPD exacerbations were prospectively enrolled from June 2016 to February 2018 in Kerala, India, excluding any with known AAT deficiency. Serum AAT levels were quantified and correlated with C-reactive protein (CRP) levels as well as postbronchodilator spirometry. Mean serum AAT level was 1.48 ± 0.27 g/L. No AAT deficiency cases were identified, although AAT and CRP both significantly increased during flares. AAT levels positively correlated with FEV1, FVC, and FEV1/FVC ratios. Patients with lower AAT had worse pulmonary status. Despite finding no AAT deficiency in this regional Indian cohort, further studies across expanded, more diverse populations are warranted to definitively establish prevalence nationwide. Temporal monitoring of AAT kinetics could help gauge exacerbation trajectories.

Using spirometry for screening and diagnosis of chronic respiratory diseases in primary health care: findings from a community health project in rural India

Background Chronic respiratory diseases (CRDs) such as Chronic obstructive pulmonary disease (COPD), Asthma and post-tuberculosis lung disease (PTLD) are a growing public health concern in India. Early diagnosis and management of CRDs require a good quality spirometry test, a technician to conduct spirometry and a chest physician to interpret the results. In India, these are not available at the primary care level. This study reports the feasibility of a large-scale CRD diagnosis and management program in primary care using a unique point-of-care spirometry solution, Briota PFT in a Box™. # Methods A community-based cross-sectional study was conducted among 15,602 adults in Dindori Taluka (subdivision), Nashik, Maharashtra state. This study was part of a holistic CRD diagnosis and management program SAVE™ (Spirometry Assisted Virtually Early). Make In India point of care solution Briota PFT in a Box™ was used. A House‐to‐house community-based assessment checklist (CBAC) survey, 4-parameter spirometry test, 15-parameter pre and post-bronchodilator spirometry test and a software-assisted medical examination by the medical officer at primary care were conducted. Software was used to generate CRD diagnosis and lung health score (LHS™). The diagnosis was verified by the chest physician. Confirmed diagnosed patients were provided treatment and offered a patient support program. Interviews were conducted with the patients, nurses, doctors and public health officials for understanding feasibility and documenting learning from program SAVE™. # Results Out of 15,602 adults surveyed, total 4,937 (31.6%) were identified as “CRD high risk”. 1231 participants based on medical examination, spirometry tests and software analysis were identified as CRD candidates by medical officers at primary care. 1154 participants out of 15,602 (7.4%) were confirmed diagnosed as CRD patients post independent evaluation by chest physicians. At the time of follow-up, 537 patients (75% of 712 patients enrolled in patient support program) reported improvement in symptoms and high satisfaction with the program. District health officer, Medical officers, nurses, Accredited Social Health Activist (ASHA) from the primary health care centers confirmed ease of use and feasibility of using Briota PFT in a Box™ in program SAVE™. Outcome and learning from program SAVE™ was documented and submitted to Ministry of Health and Family Welfare Government of India. # Conclusions CRD diagnosis and management in large scale settings in primary healthcare level using a point of care spirometry solution Briota PFT in a Box™ is highly feasible.

Impact of Using Pre- and Postbronchodilator Spirometry Reference Values in a Chinese Population.

Rationale: Spirometry reference equations that are derived from a large, nationally representative general population are warranted in China, and the impact of using prebronchodilator (pre-BD) and post-BD spirometry reference values has yet to be assessed in Chinese populations. Objectives: To present the pre-BD and post-BD spirometry reference values for Chinese adults using the China Pulmonary Health (CPH) Study. Methods: A reference population of 17,969 healthy, nonsmoking participants in the CPH Study was used to calculate the pre- and post-BD reference values for FEV1, FVC, and FEV1/FVC ratio. Pre- and post-BD reference values were applied to the entire CPH population (N = 50,991) to illustrate the divergence between the use of different references in determining disease prevalence and severity grading. Measurements and Main Results: The prevalences of airflow limitation were 5.36% using the pre-BD reference and 8.02% using the post-BD reference. Individuals who had a post-BD FEV1/FVC ratio lower than the post-BD reference value but higher than the pre-BD reference value were found to have significantly higher rates of self-reported respiratory symptoms and significantly lower values on spirometry indicators than those whose post-BD FEV1/FVC ratio was greater than the post-BD reference value. An additional 3.51% of participants were identified as having grade II-IV chronic obstructive pulmonary disease using the post-BD FEV1 predicted values. Conclusions: This study generated and applied pre- and post-BD spirometry reference values in a nationally representative Chinese adult population. Post-BD reference values may serve as an additional criterion in identifying individuals at risk for obstructive pulmonary diseases, and their diagnostic and prognostic values should be further investigated.

Novel Machine Learning Identifies 5 Asthma Phenotypes Using Cluster Analysis of Real-World Data

Asthma classification into different subphenotypes is important to guide personalized therapy and improve outcomes. To further explore asthma heterogeneity through determination of multiple patient groups by using novel machine learning (ML) approaches and large-scale real-world data. We used electronic health records of patients with asthma followed at the Cleveland Clinic between 2010 and 2021. We used k-prototype unsupervised ML to develop a clustering model where predictors were age, sex, race, body mass index, prebronchodilator and postbronchodilator spirometry measurements, and the usage of inhaled/systemic steroids. We applied elbow and silhouette plots to select the optimal number of clusters. These clusters were then evaluated through LightGBM's supervised ML approach on their cross-validated F1 score to support their distinctiveness. Data from 13,498 patients with asthma with available postbronchodilator spirometry measurements were extracted to identify 5 stable clusters. Cluster 1 included a young nonsevere asthma population with normal lung function and higher frequency of acute exacerbation (0.8 /patient-year). Cluster 2 had the highest body mass index (mean ± SD, 44.44 ± 7.83 kg/m2), and the highest proportion of females (77.5%) and Blacks (28.9%). Cluster 3 comprised patients with normal lung function. Cluster 4 included patients with lower percent of predicted FEV1 of 77.03 (12.79) and poor response to bronchodilators. Cluster 5 had the lowest percent of predicted FEV1 of 68.08 (15.02), the highest postbronchodilator reversibility, and the highest proportion of severe asthma (44.9%) and blood eosinophilia (>300 cells/μL) (34.8%). Using real-world data and unsupervised ML, we classified asthma into 5 clinically important subphenotypes where group-specific asthma treatment and management strategies can be designed and deployed.

Relationships between symptoms and lung function in asthma and/or chronic obstructive pulmonary disease in a real-life setting: the NOVEL observational longiTudinal studY.

The relationships between spirometric assessment of lung function and symptoms (including exacerbations) in patients with asthma and/or chronic obstructive pulmonary disease (COPD) in a real-life setting are uncertain. To assess the relationships between baseline post-bronchodilator (post-BD) spirometry measures of lung function and symptoms and exacerbations in patients with a physician-assigned diagnosis of asthma and/or COPD. The NOVEL observational longiTudinal studY (NOVELTY) is a global, prospective, 3-year observational study. Logistic regression analysis was used to evaluate relationships. Spirometry measures were assessed as percent predicted (%pred). Symptoms were assessed at baseline, and exacerbations were assessed at baseline and Year 1. A total of 11,181 patients in NOVELTY had spirometry data (asthma, n = 5903; COPD, n = 3881; asthma + COPD, n = 1397). A 10% lower post-BD %pred forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) - adjusted for age and sex - were significantly associated with dyspnea (modified Medical Research Council ⩾ grade 2), frequent breathlessness [St George's Respiratory Questionnaire (SGRQ)], frequent wheeze attacks (SGRQ), nocturnal awakening (Respiratory Symptoms Questionnaire; ⩾1 night/week), and frequent productive cough (SGRQ). Lower post-BD %pred FEV1 and, to a lesser extent, lower post-BD %pred FVC were significantly associated with ⩾1 physician-reported exacerbation at baseline or Year 1. This association was stronger in patients with COPD than in those with asthma. In a real-life setting, reduced lung function is consistently associated with symptoms in patients with asthma, COPD, or asthma + COPD. The relationship with exacerbations is stronger in COPD only than in asthma. clinicaltrials.gov identifier: NCT02760329 (www.clinicaltrials.gov).

Can We Use Lung Function Thresholds and Respiratory Symptoms to Identify Pre-Chronic Obstructive Pulmonary Disease? A Prospective, Population-based Cohort Study.

Rationale: The term "pre-chronic obstructive pulmonary disease" ("pre-COPD") refers to individuals at high risk of developing COPD who do not meet conventional spirometric criteria for airflow obstruction. New approaches to identifying these individuals are needed, particularly in younger populations. Objectives: To determine whether lung function thresholds and respiratory symptoms can be used to identify individuals at risk of developing COPD. Methods: The Tasmanian Longitudinal Health Study comprises a population-based cohort first studied in 1968 (at age 7 yr). Respiratory symptoms, pre- and post-bronchodilator (BD) spirometry, diffusing capacity, and static lung volumes were measured in a subgroup at age 45, and the incidence of COPD was assessed at age 53. For each lung function measure, z-scores were calculated using Global Lung Function Initiative references. The optimal threshold for best discrimination of COPD incidence was determined by the unweighted Youden index. Measurements and Main Results: Among 801 participants who did not have COPD at age 45, the optimal threshold for COPD incidence by age 53 was pre-BD FEV1/FVC z-score less than -1.264, corresponding to the lowest 10th percentile. Those below this threshold had a 36-fold increased risk of developing COPD over an 8-year follow-up period (risk ratio, 35.8; 95% confidence interval, 8.88 to 144), corresponding to a risk difference of 16.4% (95% confidence interval, 3.7 to 67.4). The sensitivity was 88%, and the specificity was 87%. Positive and negative likelihood ratios were 6.79 and 0.14, respectively. Respiratory symptoms, post-BD spirometry, diffusing capacity, and static lung volumes did not improve on the classification achieved by pre-BD FEV1/FVC alone. Conclusions: This is the first study, to our knowledge, to evaluate the discriminatory accuracy of spirometry, diffusing capacity, and static lung volume thresholds for COPD incidence in middle-aged adults. Our findings support the inclusion of pre-BD spirometry in the physiological definition of pre-COPD and indicate that pre-BD FEV1/FVC at the 10th percentile accurately identifies individuals at high risk of developing COPD in community-based settings.

Structural Predictors of Lung Function Decline in Young Smokers with Normal Spirometry.

Rationale: Chronic obstructive pulmonary disease (COPD) due to tobacco smoking commonly presents when extensive lung damage has occurred. Objectives: We hypothesized that structural change would be detected early in the natural history of COPD and would relate to loss of lung function with time. Methods: We recruited 431 current smokers (median age, 39 yr; 16 pack-years smoked) and recorded symptoms using the COPD Assessment Test (CAT), spirometry, and quantitative thoracic computed tomography (QCT) scans at study entry. These scan results were compared with those from 67 never-smoking control subjects. Three hundred sixty-eight participants were followed every six months with measurement of postbronchodilator spirometry for a median of 32 months. The rate of FEV1 decline, adjusted for current smoking status, age, and sex, was related to the initial QCT appearances and symptoms, measured using the CAT. Measurements and Main Results: There were no material differences in demography or subjective CT appearances between the young smokers and control subjects, but 55.7% of the former had CAT scores greater than 10, and 24.2% reported chronic bronchitis. QCT assessments of disease probability-defined functional small airway disease, ground-glass opacification, bronchovascular prominence, and ratio of small blood vessel volume to total pulmonary vessel volume were increased compared with control subjects and were all associated with a faster FEV1 decline, as was a higher CAT score. Conclusions: Radiological abnormalities on CT are already established in young smokers with normal lung function and are associated with FEV1 loss independently of the impact of symptoms. Structural abnormalities are present early in the natural history of COPD and are markers of disease progression. Clinical trial registered with www.clinicaltrials.gov (NCT03480347).

COPD in Never-Smokers: BOLD Australia Study.

Tobacco smoking is the major risk factor for COPD, and it is common for other risk factors in never-smokers to be overlooked. We examined the prevalence of COPD among never-smokers in Australia and identified associated risk factors. We used data from the Australia Burden of Obstructive Lung Disease (BOLD) study, a cross-section of people aged ≥40 years from six sites. Participants completed interviews and post-bronchodilator spirometry. COPD was primarily defined as an FEV1/FVC ratio <0.70 and secondarily as the ratio less than the lower limit of normal (LLN). The prevalence of COPD in the 1656 never-smokers who completed the study was 10.5% (95% CI: 9.1-12.1%) [ratio<LLN 4.6%]. The likelihood of having COPD increased with advancing age [odds ratio (OR) 4.11 in those 60-69 years and OR 8.73 in those 70 years and older], having attained up to 12 years of education (OR 1.75) compared to those with more than 12 years, having a history of asthma (OR 2.30), childhood hospitalization due to breathing problems before age 10 years (OR 2.50), or having a family history of respiratory diseases (OR 2.70). Being overweight or obese was associated with reduced prevalence of COPD compared with being normal weight. In males and females, advanced age, a history of asthma, and childhood breathing problems before age 10 were factors that elevated the likelihood of COPD. However, in males, additional factors such as a higher body mass index and a family history of respiratory diseases also contributed to increased odds of COPD. COPD was prevalent in this population of never-smokers aged 40 years and over. This finding highlights the significance of risk factors other than smoking in the development of COPD.

Long-term exposure to PM10 and respiratory health among Parisian subway workers

Exposure to ambient PM10 may increase the risk of chronic obstructive pulmonary disease (COPD) and lung function decline. We evaluated the long-term exposure to PM10 and its relationship with COPD prevalence and lung function in Parisian subway workers.Participants were randomly selected from a 15,000-subway worker cohort. Individual annual external exposure to PM10 (ePM10) was estimated using a company-specific job-exposure-matrix based on PM10 measurements conducted between 2004 and 2019 in the Parisian subway network. Mean annual inhaled PM10 exposure (iPM10) was modeled as function of ePM10 exposure, inhalation rate, and filtration efficiency of the respiratory protection used. COPD diagnosis was performed in March–May 2021 based on post-bronchodilator spirometry. The relationship between iPM10 and outcomes was assessed using logistic and linear regression models, adjusted for exposure duration and potential confounders.Amongst 254 participants with complete data, 17 were diagnosed as COPD. The mean employment duration was 23.2 ± 7.3years, with annual mean ePM10 of 71.8 ± 33.7 μg/m3 and iPM10 of 0.59 ± 0.27 μg/shift, respectively. A positive but statistically non-significant association was found for COPD prevalence with iPM10 (OR = 1.034, 95%-CI = 0.781; 1.369, per 100 ng/shift) and ePM10 (OR = 1.029, 95%-CI = 0.879; 1.207, per 10 μg/m3). No decline in lung function was associated with PM10 exposure. However, forced expiratory volume during the first second and forced vital capacity lower than normal were positively associated with exposure duration (OR = 1.125, 95%-CI = 1.004; 1.260 and OR = 1.171, 95%-CI = 0.989; 1.386 per year, respectively). Current smoking was strongly associated with COPD prevalence (OR = 6.85, 95%-CI = 1.87; 25.10) and most lung function parameters.This is the first study assessing the relationship between long-term exposure to subway PM10 and respiratory health in subway workers. The risk estimates related with subway PM10 exposure are compatible with those related to outdoor PM10 exposure in the large recent studies. Large cohorts of subway workers are necessary to confirm these findings.

Anticipating undiagnosed asthma in symptomatic adults with normal pre- and post-bronchodilator spirometry: a decision tool for bronchial challenge testing

BackgroundSome patients with asthma demonstrate normal spirometry and remain undiagnosed without further testing.ObjectiveTo determine clinical predictors of asthma in symptomatic adults with normal spirometry, and to generate a tool to help clinicians decide who should undergo bronchial challenge testing (BCT).MethodsUsing random-digit dialling and population-based case-finding, we recruited adults from the community with respiratory symptoms and no previous history of diagnosed lung disease. Participants with normal pre- and post-bronchodilator spirometry subsequently underwent BCT. Asthma was diagnosed in those with symptoms and a methacholine provocative concentration (PC20) of < 8 mg/ml. Sputum and blood eosinophils, and exhaled nitric oxide were measured. Univariate analyses identified potentially predictive variables, which were then used to construct a multivariable logistic regression model to predict asthma. Model sensitivity, specificity, and area under the receiver operating curve (AUC) were calculated.ResultsOf 132 symptomatic individuals with normal spirometry, 34 (26%) had asthma. Of those ultimately diagnosed with asthma, 33 (97%) answered ‘yes’ to a question asking whether they experienced cough, chest tightness or wheezing provoked by exercise or cold air. Other univariate predictors of asthma included female sex, pre-bronchodilator FEV1 percentage predicted, and percent positive change in FEV1 post bronchodilator. A multivariable model containing these predictive variables yielded an AUC of 0.82 (95% CI: 0.72–0.91), a sensitivity of 82%, and a specificity of 66%. The model was used to construct a nomogram to advise clinicians which patients should be prioritized for BCT.ConclusionsFour readily available patient characteristics demonstrated a high sensitivity and AUC for predicting undiagnosed asthma in symptomatic adults with normal pre- and post-bronchodilator spirometry. These characteristics can potentially help clinicians to decide which individuals with normal spirometry should be investigated with bronchial challenge testing. However, further prospective validation of our decision tool is required.

Spirometry in the diagnosis of cough variant asthma in children.

This study aimed to assess the diagnostic utility of spirometry, particularly focusing on small airway parameters, in children with cough variant asthma (CVA). This study included children aged 5-12 years with a diagnosis of CVA. Pre- and postbronchodilation spirometry parameters, including FEV1 %pred, FVC%pred, FEV1 /FVC%pred, PEF%pred, FEF25 %pred, FEF50 %pred, FEF75 %pred, MMEF%pred, were recorded. Receiver operating characteristic curves were plotted, and the area under the curve (AUC) was calculated to assess the discriminatory potential of these spirometry parameters for CVA. A prediction model based on logistic regression (LR) was performed. A total of 200 patients with CVA and 73 control subjects were included. Baseline spirometry parameters in the CVA group, except for FVC%pred, were significantly lower compared to the control group. After inhalation of salbutamol sulfate, all parameters showed significant improvement in the CVA group. However, these parameters, except for FEV1 %pred and FVC%pred, remained lower in the CVA group compared to the control group. The improvement rate of each parameter in the CVA group, except for ∆ FVC%, was significantly higher than that in the control group. △ MMEF% achieved the highest AUC of 0.797 with a threshold value of 16.09%, followed by △ FEF75 % (0.792), △ FEV1 % (0.756), and △ FEF50 % (0.747) with threshold values of 19.01%, 4.48%, and 19.4%, respectively. The clinical prediction model included four variables (age, △ FEF25 %, △ FEF75 %, and △ MMEF%) and demonstrated excellent performance distinguishing patients with and without CVA (AUC = 0.850). In the CVA group, the △ FEV1 % showed a positive correlation with small airway parameters. This study highlights that children with CVA exhibit lower pulmonary function parameters compared to healthy children. Changes in small airway parameters during bronchodilator tests can be valuable in diagnosing CVA, and the LR prediction model incorporating age and several pulmonary parameters can assist physicians in accurately identifying CVA in clinical practice.