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Recent guidelines for spirometry interpretation recommend both race-neutral reference equations and use of z score thresholds to define severity of airflow obstruction. How does the transition from race-specific to race-neutral equations impact severity classifications for patients with COPD when using % predicted vs z score thresholds, and do changes in severity correspond to clinical risk? This retrospective cohort study included Black and White patients with COPD and available spirometry from the Johns Hopkins Health System. Global Lung Function Initiative (GLI) 2012 (race-specific) equations and GLI Global (race-neutral) equations were used to determine FEV 1 % predicted and z score values. Patients were classified as having mild, moderate, or severe disease according to % predicted or z score thresholds. Associations between a change in severity classification from race-specific to race-neutral with COPD exacerbations and all-cause hospitalizations were evaluated using logistic regression. This cohort included 13,324 patients, of whom 9,232 patients (69.3%) were White (mean age, 65.7 years) and 4,092 patients (30.7%) were Black (mean age, 61.1 years). More Black than White patients showed a change in severity classification between approaches when using % predicted thresholds (20.2% vs 6.1%; P <.001), but not with z score thresholds (12.6% vs 12.3%; P =.68). An increased severity classification with a race-neutral approach was associated with increased risk of exacerbation when using z score thresholds (OR, 2.34; 95% CI, 1.51-3.63), but not when using % predicted thresholds (OR, 1.08; 95% CI, 0.61-1.93). A decreased severity classification with a race-neutral approach was associated with lower risk of exacerbation with both % predicted (OR, 0.49; 95% CI, 0.28-0.87) and z score (OR 0.67; 95% CI, 0.50-0.90) thresholds. The proportions of Black and White individuals reclassified were similar with z score thresholds, and changes in severity corresponded to clinical risk with z scores. These results support recent recommendations for use of race-neutral equations and z score thresholds for spirometry interpretation. [Display omitted] [ABSTRACT FROM AUTHOR]

BACKGROUND: Race-specific spirometry reference equations are used globally to interpret lung function for clinical, research, and occupational purposes, but inclusion of race is under scrutiny. RESEARCH QUESTION: Does including self-identified race in spirometry reference equation formation improve the ability of predicted FEV1 values to explain quantitative chest CT abnormalities, dyspnea, or Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification? STUDY DESIGN AND METHODS: Using data from healthy adults who have never smoked in both the National Health and Nutrition Survey (2007-2012) and COPDGene study cohorts, race-neutral, race-free, and race-specific prediction equations were generated for FEV1. Using sensitivity/specificity, multivariable logistic regression, and random forest models, these equations were applied in a cross-sectional analysis to populations of individuals who currently smoke and individuals who formerly smoked to determine how they affected GOLD classification and the fit of models predicting quantitative chest CT phenotypes or dyspnea. RESULTS: Race-specific equations showed no advantage relative to race-neutral or race-free equations in models of quantitative chest CT phenotypes or dyspnea. Race-neutral reference equations reclassified up to 19% of Black participants into more severe GOLD classes, while race-neutral/race-free equations may improve model fit for dyspnea symptoms relative to race-specific equations. INTERPRETATION: Race-specific equations offered no advantage over race-neutral/race-free equations in three distinct explanatory models of dyspnea and chest CT scan abnormalities. Race-neutral/race-free reference equations may improve pulmonary disease diagnoses and treatment in populations highly vulnerable to lung disease.

COPD has been found to be associated with frailty. However, longitudinal evidence for associations of COPD with frailty progression is inadequate. Furthermore, recent studies revealed a new phenotype of lung function impairment: preserved ratio impaired spirometry (PRISm) findings. Associations of PRISm findings and their transitions with frailty progression are unclear. What are the associations of PRISm findings, transitions of PRISm findings, and COPD with frailty progression? To analyze the associations of PRISm findings and COPD with frailty progression, 5,901 patients were included from the English Longitudinal Study of Ageing. Patients were classified into three lung function patterns of normal spirometry (NS) findings, PRISm findings, and COPD. Frailty progression was assessed by repeated measurements of the frailty index (FI) during follow-up. Among these 5,901 patients, 3,765 patients were included to analyze the associations of PRISm findings transitions with frailty progression. PRISm findings transitions were assessed based on the changes of lung function patterns after a 4-year interval. Linear mixed-effect models were used for statistical analyses. The median follow-up periods were 9.5 years for the analyses of PRISm findings and COPD with frailty progression and 5.8 years for PRISm findings transitions with frailty progression. When compared with participants with NS findings, patients with PRISm findings and COPD demonstrated accelerated FI progression with additional annual increases of 0.301 (95% CI, 0.211-0.392; P <.001) and 0.172 (95% CI, 0.102-0.242; P <.001), respectively. Patients who transitioned from NS findings to PRISm findings also demonstrated accelerated FI progression when compared with those with stable NS findings (β = 0.242; 95% CI, 0.008-0.476; P =.042). However, no accelerated FI progression was found in patients with PRISm findings who transitioned to NS findings (β = 0.119; 95% CI, –0.181 to 0.418; P =.438). Our findings indicate that PRISm findings and COPD are associated with accelerated frailty progression. Further studies are needed to elucidate the causality of the association of PRISm findings and COPD with frailty. [ABSTRACT FROM AUTHOR]

The lung allocation score (LAS) is a tool used to prioritize patients for lung transplantation. For patients with interstitial lung diseases (ILDs), spirometry data are used for the LAS calculation. Spirometry values such as a FVC are subjected to race-specific equations that determine expected values. The effect of race-specific equations in LAS score remains unknown. Did the use of a race-based spirometry equation lead to longer waitlist times for Black patients? We performed a retrospective analysis of patients listed for lung transplantation from 2005 through 2020 using publicly available data from the United Network for Organ Sharing. We recalculated LAS scores for Black patients using White-specific equations with the available variables. The primary objective was to evaluate the effect of race-specific equations on LAS scores and time on the transplant waitlist. A total of 33,845 patients listed for lung transplantation were included in the analysis. White patients were listed at lower LAS scores, a higher proportion of White patients underwent transplantation, and White patients died on the waitlist at lower rates. When recalculating LAS scores using White-specific equations, Black patients with ILD had up to a 1.9-point higher score, which resulted in additional waitlist time. Race-specific equations led to longer wait times in Black patients listed for lung transplantation. The use of race-based equations widened already known disparities in pulmonary transplantation. [Display omitted] [ABSTRACT FROM AUTHOR]

Race-specific spirometry reference equations are used globally to interpret lung function for clinical, research, and occupational purposes, but inclusion of race is under scrutiny. Does including self-identified race in spirometry reference equation formation improve the ability of predicted FEV 1 values to explain quantitative chest CT abnormalities, dyspnea, or Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification? Using data from healthy adults who have never smoked in both the National Health and Nutrition Survey (2007-2012) and COPDGene study cohorts, race-neutral, race-free, and race-specific prediction equations were generated for FEV 1. Using sensitivity/specificity, multivariable logistic regression, and random forest models, these equations were applied in a cross-sectional analysis to populations of individuals who currently smoke and individuals who formerly smoked to determine how they affected GOLD classification and the fit of models predicting quantitative chest CT phenotypes or dyspnea. Race-specific equations showed no advantage relative to race-neutral or race-free equations in models of quantitative chest CT phenotypes or dyspnea. Race-neutral reference equations reclassified up to 19% of Black participants into more severe GOLD classes, while race-neutral/race-free equations may improve model fit for dyspnea symptoms relative to race-specific equations. Race-specific equations offered no advantage over race-neutral/race-free equations in three distinct explanatory models of dyspnea and chest CT scan abnormalities. Race-neutral/race-free reference equations may improve pulmonary disease diagnoses and treatment in populations highly vulnerable to lung disease. [Display omitted] [ABSTRACT FROM AUTHOR]

Studies examining agreement between home and clinic spirometry in patients with asthma are limited, with conflicting results. Understanding the strengths and limitations of telehealth and home spirometry is particularly important considering the SARS-CoV-2 pandemic. How well do home and clinic measurements of trough FEV 1 agree in patients with uncontrolled asthma? This post hoc analysis used trough FEV 1 data from the randomized double-anonymized parallel-group phase 3A CAPTAIN (205715; NCT02924688) and phase 2B 205832 (NCT03012061) trials in patients with uncontrolled asthma. CAPTAIN evaluated the impact of adding umeclidinium to fluticasone furoate/vilanterol via a single inhaler; the 205832 trial investigated adding umeclidinium to fluticasone furoate vs placebo. Trough FEV 1 measurements were collected via home spirometry and supervised in-person spirometry in the research clinic. To compare home and clinic spirometry, we examined the time-course analyses of home and clinic trough FEV 1 , and generated post hoc Bland-Altman plots to assess agreement between home and clinic spirometry. Data from 2,436 patients (CAPTAIN trial) and 421 patients (205832 trial) were analyzed. Treatment-related improvements in FEV 1 were observed in both trials, using home and clinic spirometry. Improvements measured by home spirometry were of lower magnitude and less consistent than clinic measurements. Bland-Altman plots suggested poor agreement between home and clinic trough FEV 1 at baseline and week 24. This post hoc comparison of home and clinic spirometry is the largest conducted in asthma. Results showed that home spirometry was less consistent than and lacked agreement with clinic spirometry, suggesting that unsupervised home readings are not interchangeable with clinic measurements. However, these findings may only be applicable to home spirometry using the specific device and coaching methods employed in these studies. Postpandemic, further research to optimize home spirometry use is needed. ClinicalTrials.gov; Nos.: NCT03012061 and NCT02924688; URL: www.clinicaltrials.gov [ABSTRACT FROM AUTHOR]

The prospective associations of preserved ratio impaired spirometry (PRISm) with new-onset macrovascular and microvascular complications and mortality among individuals with type 2 diabetes (T2D) and whether PRISm enhances the prediction ability of an established office-based risk score remain to be elucidated. Can PRISm be used as a predictor of poor prognosis in individuals with T2D? We included 20,047 study participants with T2D and complete data on spirometry at recruitment from the UK Biobank cohort. Multivariable Cox proportional hazards models were used to assess the associations of baseline PRISm (FEV 1 to FVC ratio, ≥ 0.70; FEV 1 , < 80% predicted) with subsequent risks of incident stroke (any type), ischemic stroke, myocardial infarction, unstable angina, coronary heart disease, diabetic retinopathy, diabetic kidney disease, all-cause mortality, cardiovascular mortality, and respiratory mortality. For this cohort analysis, 4,521 patients (22.55% of participants with T2D) showed comorbid PRISm at baseline. Over a median follow-up of 11.52 to 11.87 years, patients with T2D with PRISm at baseline showed higher risks than those with normal spirometry findings of various T2D complications developing and mortality; the adjusted hazard ratios for PRISm were 1.413 (95% CI, 1.187-1.681) for stroke (any type), 1.382 (95% CI, 1.129-1.690) for ischemic stroke, 1.253 (95% CI, 1.045-1.503) for myocardial infarction, 1.206 (95% CI, 1.086-1.339) for coronary heart disease, 1.311 (95% CI, 1.141-1.506) for diabetic retinopathy, 1.384 (95% CI, 1.190-1.610) for diabetic kidney disease, 1.337 (95% CI, 1.213-1.474) for all-cause mortality, 1.597 (95% CI, 1.296-1.967) for cardiovascular mortality, and 1.559 (95% CI, 1.189-2.044) for respiratory mortality, respectively. The addition of PRISm significantly improved the reclassification ability, based on the net reclassification index, of an office-based risk score by 15.53% (95% CI, 10.14%-19.63%) to 33.60% (95% CI, 20.90%-45.79%). Individuals with T2D with comorbid PRISm, accounting for a considerable proportion of the population with T2D, showed significantly increased risks of adverse macrovascular and microvascular complications and mortality. [ABSTRACT FROM AUTHOR]

It has been observed widely that, on average, Black individuals in the United States have lower FVC than White individuals, which is thought to reflect a combination of genetic, environmental, and socioeconomic factors that are difficult to disentangle. Debate therefore persists even after the American Thoracic Society's 2023 guidelines recommending race-neutral pulmonary function test (PFT) result interpretation strategies. Advocates of race-based PFT results interpretation argue that it allows for more precise measurement and will minimize disease misclassification. In contrast, recent studies have shown that low lung function in Black patients has clinical consequences. Furthermore, the use of race-based algorithms in medicine in general is increasingly being questioned for its risk of perpetuating structural health care disparities. Given these concerns, we believe it is time to adopt a race-neutral approach, but note that more research is urgently needed to understand how race-neutral approaches impact PFT results interpretation, clinical decision-making, and patient outcomes. In this brief case-based discussion, we offer a few examples of how a race-neutral PFT results interpretation strategy will impact individuals from racial and ethnic minority groups at different scenarios and stages of life. [ABSTRACT FROM AUTHOR]

The acute cardiovascular and pulmonary effects of contemporary electronic nicotine delivery systems (ENDS) in long-term users are not known. What are the cardiovascular and pulmonary responses to an acute 15-min product use challenge with ENDS and combustible cigarettes in regular nicotine-containing product users compared with control participants who do not use tobacco or vape? Observational challenge study before and after nicotine-containing product use of 395 individuals who used ENDS exclusively (n = 164; exhaled carbon monoxide level, < 5 parts per million [ppm]; positive urine NicCheck I [Mossman Associates] results, 82%; fourth-generation ENDS), participants who smoked cigarettes exclusively (n = 117; carbon monoxide level, > 5 ppm; positive urine NicCheck I results), and control participants (n = 114; carbon monoxide level, < 5 ppm; negative urine NicCheck I results). During the 15-min product challenge, cigarette users took a median of 14.0 puffs (interquartile range [IQR], 9.3 puffs); ENDS users took 9.0 puffs (IQR, 7.5 puffs; P <.001). After product challenge, compared with control participants, ENDS users showed greater increases in adjusted mean differences in systolic BP (5.6 mm Hg [95% CI, 4.4-6.8 mm Hg] vs 2.3 mm Hg [95% CI, 0.8-3.8 mm Hg]; P =.001), diastolic BP (4.2 mm Hg [95% CI, 3.3-5.0 mm Hg] vs 2.0 mm Hg [95% CI, 1.1-3.0 mm Hg; P =.003), and heart rate (4.8 beats/min [95% CI, 4.0-5.6 beats/min] vs –1.3 beats/min [95% CI, –2.2 to –0.3 beats/min]; P <.001) and greater reductions in brachial artery diameter (–0.011 cm [95% CI, –0.013 to 0.009 cm] vs –0.006 cm [95% CI, –0.004 to –0.009 cm]; P =.003), time-domain heart rate variability (–7.2 ms [95% CI, –10.5 to –3.7 ms] vs 3.6 ms [95% CI, 1.6-9.3 ms]; P =.001), and FEV 1 (ENDS: –4.1 [95% CI, –5.4 to –2.8] vs control participants: –1.1 [95% CI, –2.7 to 0.6]; P =.005) with values similar to those of cigarette users. ENDS users performed worse than control participants on all exercise parameters, notably metabolic equivalents (METs; adjusted mean difference, 1.28 METs [95% CI, 0.73-1.83 METs]; P <.001) and 60-s heart rate recovery (adjusted mean difference, 2.9 beats/min [95% CI, 0.7-5.0 beats/min]; P =.008). ENDS users had acute worsening of blood pressure, heart rate, and heart rate variability, as well as vasoconstriction, impaired exercise tolerance, and increased airflow obstruction after vaping, compared to control participants. ClinicalTrials.gov; No.: NCT03863509; URL: www.clinicaltrials.gov [Display omitted] [ABSTRACT FROM AUTHOR]

Individuals with COPD and preserved ratio impaired spirometry (PRISm) findings in clinical settings have an increased risk of cardiovascular disease (CVD). Do individuals with mild to moderate or worse COPD and PRISm findings in community settings have a higher prevalence and incidence of CVD compared with individuals with normal spirometry findings? Can CVD risk scores be improved when impaired spirometry is added? The analysis was embedded in the Canadian Cohort Obstructive Lung Disease (CanCOLD). Prevalence of CVD (ischemic heart disease [IHD] and heart failure [HF]) and their incidence over 6.3 years were compared between groups with impaired and normal spirometry findings using logistic regression and Cox models, respectively, adjusting for covariables. Discrimination of the pooled cohort equations (PCE) and Framingham risk score (FRS) in predicting CVD were assessed with and without impaired spirometry. Participants (n = 1,561) included 726 people with normal spirometry findings and 835 people with impaired spirometry findings (COPD Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 1 disease, n = 408; GOLD stage ≥ 2, n = 331; PRISm findings, n = 96). Rates of undiagnosed COPD were 84% in GOLD stage 1 and 58% in GOLD stage ≥ 2 groups. Prevalence of CVD (IHD or HF) was significantly higher among individuals with impaired spirometry findings and COPD compared with those with normal spirometry findings, with ORs of 1.66 (95% CI, 1.13-2.43; P =.01∗) (∗ indicates statistical significane with P <.05) and 1.55 (95% CI, 1.04-2.31; P =.033∗), respectively. Prevalence of CVD was significantly higher in participants having PRISm findings and COPD GOLD stage ≥ 2, but not GOLD stage 1. CVD incidence was significantly higher, with hazard ratios of 2.07 (95% CI, 1.10-3.91; P =.024∗) for the impaired spirometry group and 2.09 (95% CI, 1.10-3.98; P =.024∗) for the COPD group compared to individuals with normal spirometry findings. The difference was significantly higher among individuals with COPD GOLD stage ≥ 2, but not GOLD stage 1. The discrimination for predicting CVD was low and limited when impaired spirometry findings were added to either risk score. Individuals with impaired spirometry findings, especially those with moderate or worse COPD and PRISm findings, have increased comorbid CVD compared with their peers with normal spirometry findings, and having COPD increases the risk of CVD developing. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate physiological phenotypes of asthma in obesity. Do physiological responses during bronchoconstriction distinguish different groups of asthma in people with obesity, and also differentiate from responses simply related to obesity? Cross-sectional study of people with obesity (31 with asthma and 22 without lung disease). Participants underwent methacholine challenge testing with measurement of spirometry and respiratory system impedance by oscillometry. Participants had class III obesity (BMI, 46.7 ± 6.6 kg/m2 in control subjects and 47.2 ± 8.2 kg/m2 in people with asthma). Most participants had significant changes in peripheral airway impedance in response to methacholine: in control subjects, resistance at 5 Hz measured by oscillometry increased by 45% ± 27% and area under the reactance curve (AX) by 268% ± 236% in response to 16 mg/mL methacholine; in people with asthma, resistance at 5 Hz measured by oscillometry increased by 52% ± 38% and AX by 361% ± 295% in response to provocation concentration producing a 20% fall in FEV 1 dose of methacholine. These responses suggest that obesity predisposes to peripheral airway reactivity. Two distinct groups of asthma emerged based on respiratory system impedance: one with lower reactance (baseline AX, 11.8; interquartile range, 9.9-23.4 cm H 2 O/L) and more concordant bronchoconstriction in central and peripheral airways; the other with high reactance (baseline AX, 46.7; interquartile range, 23.2-53.7 cm H 2 O/L) and discordant bronchoconstriction responses in central and peripheral airways. The high reactance asthma group included only women, and reported significantly more gastroesophageal reflux disease, worse chest tightness, more wheeze, and more asthma exacerbations than the low reactance group. Peripheral airway reactivity detected by oscillometry is common in obese control subjects and obese people with asthma. There is a subgroup of obese asthma characterized by significant peripheral airway dysfunction by oscillometry out of proportion to spirometric airway dysfunction. This peripheral dysfunction represents clinically significant respiratory disease not readily assessed by spirometry. [ABSTRACT FROM AUTHOR]

Background: Preserved ratio impaired spirometry (PRISm) is a heterogeneous condition characterized by a normal forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio with underlying impairment of pulmonary function. Data relating to the association of baseline and trajectories of PRISm with diverse cardiovascular outcomes is sparse.Research Question: How do baseline and trajectories of PRISm impact subsequent cardiovascular events?Study Design and Methods: In the UK Biobank cohort study, we included cardiovascular disease (CVD) free participants with spirometry (FEV1 and FVC values) at baseline (2006-2010). Participants with baseline spirometry and follow-up spirometry (2014-2020) were included in the lung function trajectory analysis. Cox proportional hazards multivariable regression was performed to evaluate the outcomes of major adverse cardiovascular events (MACE), incident myocardial infarction (MI), stroke, heart failure (HF), and CVD mortality in association with lung function.Results: For baseline analysis (329,954 participants), the multivariable adjusted hazard ratios (HR) for participants had PRISm (vs. normal spirometry) were 1.26 (95% confidence interval (CI) 1.17-1.35) for MACE, 1.12 (1.01-1.25) for MI, 1.88 (1.72-2.05) for HF, 1.26 (1.13-1.40) for stroke, and 1.55 (1.37-1.76) for CVD mortality, respectively. A total of 22,781 participants had a follow-up spirometry after average of 8.9 years. Trajectory analysis showed that persistent PRISm (HR 1.96; 95% CI 1.24-3.09) and airflow obstruction (HR 1.43; 95% CI 1.00-2.04) was associated with a higher incidence of MACE versus consistently normal lung function. Compared with persistent PRISm, changing from PRISm to normal spirometry was associated with a lower incidence of MACE (HR 0.42; 95% CI 0.19-0.99).Interpretation: Individuals with baseline or persistent PRISm were at a higher risk of diverse cardiovascular outcomes even after adjusting for a wide range of confounding factors. However, individuals who transitioned from PRISm to normal had a similar cardiovascular risk as those with normal lung function. [ABSTRACT FROM AUTHOR]

Background: Impaired lung function is associated with a higher risk of developing lung cancer. However, lung function is a dynamic variable and must be evaluated longitudinally. This study reports on the relationship between accelerated lung function decline and development of lung cancer.Research Question: Is accelerated lung function decline associated with the development of lung cancer?Study Design and Methods: A longitudinal, observational study was performed by using epidemiologic data from two population-based studies comprising subjects assessed biannually from 2001 to 2019 in South Korea. Eligible subjects were between 40 and 69 years of age and were followed up by using spirometry. Spirometry measurements were made at each follow-up. Patients with a decline in FEV1 > 60 mL per year were defined as rapid FEV1 decliners. The relationship between lung cancer and rapid FEV1 decline was evaluated by using adjusted Cox regression models with covariates, including age, sex, smoking history, FEV1/FVC, and WBC count.Results: Among the 8,549 eligible subjects, 1,287 (15.1%) had rapid FEV1 decline, and 48 (0.6%) had newly developed lung cancer. The risk of lung cancer development was increased in the subjects aged ≥ 45 years and those with ≥ 30 pack-years of smoking, low baseline FEV1/FVC, low forced expiratory flow between 25% and 75% of vital capacity, rapid FEV1 decline, and increased WBC count. Rapid FEV1 decline was an independent risk factor for lung cancer development (adjusted hazard ratio, 2.34; 95% CI, 1.28-4.28; P = .006). Time-dependent net reclassification improvement showed a benefit of FEV1 decline rate in determining subjects at risk of lung cancer when added to conventional practice (categorical, 0.32 [95% CI, 0.00-0.64]; continuous, 0.83 [95% CI, 0.14-1.25]).Interpretation: The FEV1 decline rate may be a potential biomarker for lung cancer development. Further study is needed to identify whether patients with rapid FEV1 decline warrant lung cancer assessment or screening. [ABSTRACT FROM AUTHOR]

Background: The effect of nonobstructive chronic bronchitis (CB) on mortality is unclear.Research Question: Is nonobstructive CB associated with increased all-cause mortality?Study Design and Methods: We conducted a systematic literature review and meta-analysis to assess the association of nonobstructive CB and all-cause mortality. We searched for articles that included both CB and mortality in the title, abstract, or both in PubMed and EMBASE. We excluded studies in which participants demonstrated obstructive spirometry findings and studies in which CB and mortality were not defined. We used the Newcastle-Ottawa Quality Assessment Scale to assess study quality. We pooled adjusted hazard ratios (HRs) using the random effects model and inverse variance weighting. We conducted stratified analysis by the definition of CB and smoking status. We used Cochran's Q and I2 to assess for heterogeneity. We assessed publication bias by visual inspection of a funnel plot.Results: Of 5,014 titles identified, eight fulfilled the inclusion and exclusion criteria. Overall nonobstructive CB was associated with all-cause mortality (HR, 1.37; 95% CI, 1.26-1.50) with no statistically significant heterogeneity (P = .14; I2 = 29%). Nonobstructive CB was associated with increased mortality in studies that defined CB as any respiratory symptoms (broad definition; HR, 1.28; 95% CI, 1.10-1.48; I2 = 0%) as well as in the rest of the studies (HR, 1.40; 95% CI, 1.26-1.56; I2 = 37%). Nonobstructive CB was associated with increased mortality in ever smokers (HR, 1.49; 95% CI, 1.35-1.64; I2 = 0%), but was not associated with increased mortality in never smokers (HR, 1.22; 95% CI, 0.90-1.66), and moderate heterogeneity was found (P = .10; I2 = 49%). The funnel plot did not indicate evidence of a publication bias because it showed symmetrical distribution of studies.Interpretation: Nonobstructive CB is associated with increased all-cause mortality, and this association seems to be present only in current and former smokers. Further research should investigate whether this high-risk population may benefit from early therapeutic intervention.Trial Registry: PROSPERO; No.: CRD42021253596; URL: www.crd.york.ac.uk/prospero. [ABSTRACT FROM AUTHOR]

Background: Variation in genetic ancestry among genetically admixed racial and ethnic groups may influence the fit of guideline-recommended spirometry reference equations, which rely on self-identified race and ethnicity.Research Question: What is the influence of genetic ancestry on the fit of race- and ethnicity-based spirometry reference equations in populations of genetically admixed children?Study Design and Methods: Cross-sectional fit of guideline-recommended race- and ethnicity-based spirometry reference equations was evaluated in healthy control participants from case-control studies of asthma. Anthropometry, blood samples, and spirometric measurements were obtained for 599 genetically admixed children 8 to 21 years of age. Genetic ancestry was estimated using genome-wide genotype data. Equation fit, measured as a mean z score, was assessed in self-identified African American (n = 275) and Puerto Rican (n = 324) children as well as genetic ancestry-defined strata of each population.Results: For African American children, African American-derived equations fit for predicting FEV1 and FVC in those with an African ancestry more than the median (81.4%-100.0%), whereas composite equations for "other/mixed" populations fit for predicting FEV1 and FVC in those with African ancestry at or less than the median (30.7%-81.3%). For Puerto Rican children with African ancestry at or less than the median (6.4%-21.3%), White-derived equations fit both FEV1 and FVC, whereas for those with African ancestry more than the median (21.4%-87.5%), White-derived equations fit the FEV1 and the composite equations fit the FVC.Interpretation: Guideline-recommended spirometry reference equations yielded biased estimates of lung function in genetically admixed children with high variation of African ancestry. Spirometry could benefit from reference equations that incorporate genetic ancestry, either for more precise application of the current equations or the derivation and use of new equations. [ABSTRACT FROM AUTHOR]

Background: Azithromycin has immunomodulatory actions, and its beneficial effects have been demonstrated in asthmatic adults. Data on children are limited.Research Question: Does the addition of oral azithromycin to standard therapy in children with poorly controlled asthma improve asthma control compared with standard treatment alone?Study Design and Methods: This open-label randomized controlled trial included children (5-15 years of age) with poorly controlled asthma defined by Asthma Control Test (ACT) and Childhood Asthma Control Test (CACT) score of ≤ 19. They were randomized to receive azithromycin (10 mg/kg) three times weekly for 3 months along with standard treatment or standard treatment alone. The primary outcome was the ACT and CACT scores at 3 months. Secondary outcomes were asthma control according to Global Initiative for Asthma (GINA) guidelines, the number of exacerbations, change in spirometry parameters, change in fractional exhaled nitric oxide (Feno) level, positive throat swab results, and side effects.Results: The trial included 120 children (89 boys; 60 in each group). The mean ± SD age was 9.9 ± 3 years. The baseline parameters were similar between the groups. Mean ± SD ACT and CACT scores (available for 115 children) at 3 months of intervention were 21.71 ± 2.17 vs 18.33 ± 2.19 (P < .001) in the azithromycin and control groups, respectively. The numbers of children with well-controlled asthma according to GINA guidelines were 41 of 56 vs 10 of 56 in the azithromycin and control groups, respectively (P < .001). The median number of exacerbations requiring emergency visit and steroid use were fewer in the azithromycin group: 0 (interquartile range [IQR], 3) vs 1 [IQR, 6]; P < .001). No difference was found in Feno level, spirometry parameters, positive throat swab results, and adverse effects between the groups.Interpretation: The use of azithromycin in children with poorly controlled asthma resulted in improved asthma control and reduced exacerbations.Trial Registry: Clinical Trials Registry - India; No.: CTRI/2019/06/019727; URL: www.ctri.nic.in. [ABSTRACT FROM AUTHOR]

Background: Some people have characteristics of both asthma and COPD (asthma-COPD overlap), and evidence suggests they experience worse outcomes than those with either condition alone.Research Question: What is the genetic architecture of asthma-COPD overlap, and do the determinants of risk for asthma-COPD overlap differ from those for COPD or asthma?Study Design and Methods: We conducted a genome-wide association study in 8,068 asthma-COPD overlap case subjects and 40,360 control subjects without asthma or COPD of European ancestry in UK Biobank (stage 1). We followed up promising signals (P < 5 × 10-6) that remained associated in analyses comparing (1) asthma-COPD overlap vs asthma-only control subjects, and (2) asthma-COPD overlap vs COPD-only control subjects. These variants were analyzed in 12 independent cohorts (stage 2).Results: We selected 31 independent variants for further investigation in stage 2, and discovered eight novel signals (P < 5 × 10-8) for asthma-COPD overlap (meta-analysis of stage 1 and 2 studies). These signals suggest a spectrum of shared genetic influences, some predominantly influencing asthma (FAM105A, GLB1, PHB, TSLP), others predominantly influencing fixed airflow obstruction (IL17RD, C5orf56, HLA-DQB1). One intergenic signal on chromosome 5 had not been previously associated with asthma, COPD, or lung function. Subgroup analyses suggested that associations at these eight signals were not driven by smoking or age at asthma diagnosis, and in phenome-wide scans, eosinophil counts, atopy, and asthma traits were prominent.Interpretation: We identified eight signals for asthma-COPD overlap, which may represent loci that predispose to type 2 inflammation, and serious long-term consequences of asthma. [ABSTRACT FROM AUTHOR]

Background: Small airways are known to be affected early in the course of COPD; however, traditional spirometric indices may not accurately identify small airways disease.Research Question: Can forced expiratory volume in 3 s/forced expiratory volume in 6 s (FEV3/FEV6) identify early airflow abnormalities and predict future clinically important respiratory-related outcomes, including development of COPD?Study Design and Methods: The study included 832 current and former smokers with post-bronchodilator FEV1/FVC ≥ 0.7 from the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) cohort. Participants were classified as having a reduced pre-bronchodilator FEV3/FEV6 based on lower limit of normal (LLN) values. Repeatability analysis was performed for FEV3 and FEV6. Regression modeling was used to evaluate the relationship between baseline FEV3/FEV6 and outcome measures, including functional small airways disease, on thoracic imaging and respiratory exacerbations. Interval-censored analysis was used to assess progression to COPD.Results: FEV3/FEV6 less than the LLN at baseline, defined as reduced compared with FEV3/FEV6 at or above the LLN, was associated with lower FEV1, poorer health status (St. George's Respiratory Questionnaire score), more emphysema, and more functional small airways disease on quantitative imaging. FEV3 and FEV6 showed excellent agreement between repeat measurements. A reduced FEV3/FEV6 was associated with increased odds of a severe respiratory exacerbation within the first year of follow-up and decreased time to first exacerbation. A low FEV3/FEV6 was also associated with development of COPD according to spirometry results (post-bronchodilator FEV1/FVC < 0.7) during study follow-up.Interpretation: FEV3/FEV6 is a routinely available and repeatable spirometric index that can be useful in the evaluation of early airflow obstruction in current and former smokers without COPD. A reduced FEV3/FEV6 can identify those at risk for future development of COPD and respiratory exacerbations.Clinical Trial Registration: ClinicalTrials.gov; No.: NCT01969344; URL: www.Clinicaltrials: gov: ClinicalTrials.gov. [ABSTRACT FROM AUTHOR]

Background: Most pulmonary conditions reduce FVC, but studies of patients with combined pulmonary fibrosis and emphysema demonstrate that reductions in FVC are less than expected when these two conditions coexist clinically.Research Question: Do interstitial lung abnormalities (ILAs), chest CT imaging findings that may suggest an early stage of pulmonary fibrosis in individuals with undiagnosed disease, affect the association between emphysema and FVC?Study Design and Methods: Measures of ILA and emphysema were available for 9,579 and 5,277 participants from phases 1 (2007-2011) and 2 (2012-2016) of the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease Study (COPDGene), respectively. ILA were defined by Fleischner Society guidelines. Adjusted linear regression models were used to assess the associations and interactions among ILA, emphysema, measures of spirometry, and lung function.Results: ILA were present in 528 (6%) and 580 (11%) of participants in phases 1 and 2 of COPDGene, respectively. ILA modified the association between emphysema and FVC (P < .0001 for interaction) in both phases. In phase 1, in those without ILA, a 5% increase in emphysema was associated with a reduction in FVC (-110 mL; 95% CI, -121 to -100 mL; P < .0001); however, in those with ILA, it was not (-11 mL; 95% CI, -53 to 31; P = .59). In contrast, no interaction was found between ILA and emphysema on total lung capacity or on diffusing capacity of carbon monoxide.Interpretation: The presence of ILA attenuates the reduction in FVC associated with emphysema. [ABSTRACT FROM AUTHOR]

Background: Although guidelines long have recommended objective pulmonary function testing to diagnose asthma and COPD, many primary care patients receive a clinical diagnosis of asthma or COPD without objective testing. This often leads to unnecessary treatment with associated incremental costs and side effects and delays actual diagnosis.Research Question: What are the barriers and enablers to lung function testing for asthma, COPD, or both in primary care?Study Design and Methods: We searched the literature for qualitative and quantitative studies reporting barriers, enablers, or both to in-office or out-of-office lung function testing for diagnosing asthma, COPD, or both in primary care. Two reviewers independently screened abstracts and full texts, assessed methodologic quality using the Mixed Methods Appraisal Tool, and extracted data from included studies. Identified barriers and enablers were categorized using the Theoretical Domains Framework (TDF), applying a pre-established coding manual.Results: We identified 7,988 unique articles, reviewed 336 full-text articles, and included 18 studies in this systematic review. Of these 18, 12 were quantitative, three were qualitative, and three used mixed methods. All 18 addressed in-office testing and 11 also addressed out-of-office testing. Barriers and enablers overlapped for asthma and COPD, and in-office and out-of-office settings. We identified more reported barriers (eg, lack of knowledge of the usefulness of spirometry) than enablers (eg, skills for performing reliable spirometry). Barriers mapped to nine (of a possible 14) TDF domains (for both in-office and out-of-office settings). Enablers mapped to three domains for in-office testing and five domains for out-of-office testing.Interpretation: Barriers to objective testing for airway disease in primary care are complex and span many theoretical domains. Correspondingly, a successful intervention must leverage multiple behavior change techniques. A theory-based, multifaceted intervention to address underuse of diagnostic testing for asthma or COPD now should be developed and tested. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: There are few clinically useful circulating biomarkers of lung function and lung disease. We hypothesized that genome-wide association studies (GWAS) of circulating proteins in conjunction with GWAS of pulmonary traits represents a clinically relevant approach to identifying causal proteins and therapeutically useful insights into mechanisms related to lung function and disease.Study Question: Can an integrative genomic strategy using GWAS of plasma soluble receptor for advanced glycation end-products (sRAGE) levels in conjunction with GWAS of lung function traits identify putatively causal relations of sRAGE to lung function?Study Design and Methods: Plasma sRAGE levels were measured in 6,861 Framingham Heart Study participants and GWAS of sRAGE was conducted to identify protein quantitative trait loci (pQTL), including cis-pQTL variants at the sRAGE protein-coding gene locus (AGER). We integrated sRAGE pQTL variants with variants from GWAS of lung traits. Colocalization of sRAGE pQTL variants with lung trait GWAS variants was conducted, and Mendelian randomization was performed using sRAGE cis-pQTL variants to infer causality of sRAGE for pulmonary traits. Cross-sectional and longitudinal protein-trait association analyses were conducted for sRAGE in relation to lung traits.Results: Colocalization identified shared genetic signals for sRAGE with lung traits. Mendelian randomization analyses suggested protective causal relations of sRAGE to several pulmonary traits. Protein-trait association analyses demonstrated higher sRAGE levels to be cross-sectionally and longitudinally associated with preserved lung function.Interpretation: sRAGE is produced by type I alveolar cells, and it acts as a decoy receptor to block the inflammatory cascade. Our integrative genomics approach provides evidence for sRAGE as a causal and protective biomarker of lung function, and the pattern of associations is suggestive of a protective role of sRAGE against restrictive lung physiology. We speculate that targeting the AGER/sRAGE axis may be therapeutically beneficial for the treatment and prevention of inflammation-related lung disease. [ABSTRACT FROM AUTHOR]

Background: Ozone effects on lung function are particularly important to understand in the context of the air pollution-health outcomes epidemiologic literature, given the complex relationships between ozone and other air pollutants with known lung function effects.Research Question: What has been learned about the association between ozone exposures and lung function from epidemiology studies published from 2013 through 2020?Study Design and Methods: On March 18, 2018, and September 8, 2020, PubMed was searched using the terms health AND ozone, filtering to articles in English and about humans, from 2013 or later. An additional focused review searching for ozone AND (lung function OR FEV1OR FVC) was performed June 26, 2021. Articles were selected for this review if they reported a specific relationship between a lung function outcome and ozone exposure.Results: Of 3,271 articles screened, 53 ultimately met criteria for inclusion. A systematic review with assessment of potential for bias was conducted, but a meta-analysis was not carried out because of differences in exposure duration and outcome quantification. Consistent evidence exists of small decreases in children's lung function, even associated with very low levels of short-term ozone exposure. The effects on adult lung function from exposure to low-level, short-term ozone are less clear, although ozone-associated decrements may occur in the elderly. Finally, long-term ozone exposure decreases both lung function and lung function growth in children, although few new studies have examined long-term ozone and lung function in adults.Interpretation: Much of this literature involves concentrations below the current US Environmental Protection Agency's National Ambient Air Quality Standard of 70 parts per billion over an 8-h averaging time, suggesting that this current standard may not protect children adequately from ozone-related decrements in lung function. [ABSTRACT FROM AUTHOR]

BackgroundCOPD is the third most frequent cause of death globally, with much of this burden attributable to household biomass smoke exposure in developing countries. As biomass smoke exposure is also associated with cardiovascular disease, lower respiratory infection, lung cancer, and cataracts, it presents an important target for public health intervention.MethodsLung function in Guatemalan women exposed to wood smoke from open fires was measured throughout the Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) stove intervention trial and continued during the Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter (CRECER) cohort study. In RESPIRE, early stove households received a chimney woodstove at the beginning of the 18-month trial, and delayed stove households received a stove at trial completion. Personal exposure to wood smoke was assessed with exhaled breath carbon monoxide (CO) and personal CO tubes. Change in lung function between intervention groups and as a function of wood smoke exposure was assessed using random effects models.ResultsOf 306 women participating in both studies, acceptable spirometry was collected in 129 early stove and 136 delayed stove households (n = 265), with a mean follow-up of 5.6 years. Despite reduced wood smoke exposures in early stove households, there were no significant differences in any of the measured spirometric variables during the study period (FEV1, FVC, FEV1/FVC ratio, and annual change) after adjustment for confounding.ConclusionsIn these young Guatemalan women, there was no association between lung function and early randomization to a chimney stove or personal wood smoke exposure. Future stove intervention trials should incorporate cleaner stoves, longer follow-up, or potentially susceptible groups to identify meaningful differences in lung function.

The existing coverage criteria for home noninvasive ventilation (NIV) do not recognize the diversity of hypoventilation syndromes and advances in technologies. This document summarizes the work of the hypoventilation syndromes Technical Expert Panel working group. The most pressing current coverage barriers identified were: (1) overreliance on arterial blood gases (particularly during sleep); (2) need to perform testing on prescribed oxygen; (3) requiring a sleep study to rule out OSA as the cause of sustained hypoxemia; (4) need for spirometry; (5) need to show bilevel positive airway pressure (BPAP) without a backup rate failure to qualify for BPAP spontaneous/timed; and (6) qualifying hospitalized patients for home NIV therapy at the time of discharge. Critical evidence support for changes to current policies includes randomized controlled trial evidence and clinical practice guidelines. To decrease morbidity and mortality by achieving timely access to NIV for patients with hypoventilation, particularly those with obesity hypoventilation syndrome, we make the following key suggestions: (1) given the significant technological advances, we advise acceptance of surrogate noninvasive end-tidal and transcutaneous Pco2 and venous blood gases in lieu of arterial blood gases; (2) not requiring Pco2 measures while on prescribed oxygen; (3) not requiring a sleep study to avoid delays in care in patients being discharged from the hospital; (4) remove spirometry as a requirement; and (5) not requiring BPAP without a backup rate failure to approve BPAP spontaneous/timed. The overarching goal of the Technical Expert Panel is to establish pathways that improve clinicians' management capability to provide Medicare beneficiaries access to appropriate home NIV therapy. Adoption of these proposed suggestions would result in the right device, for the right type of patient with hypoventilation syndromes, at the right time. [ABSTRACT FROM AUTHOR]

Background: COPD medications reduce exacerbations and improve quality of life. Despite this, some individuals do not receive medications recommended by practice guidelines.Research Question: How common is nonreceipt of recommended medications among people with COPD, and what factors are associated with nonreceipt?Study Design and Methods: This population cohort study was conducted in Ontario, Canada, a province with universal health care insurance and medication coverage for those aged ≥ 65 years. Health administrative data were used to identify people aged ≥ 66 years with physician-diagnosed COPD as of 2018 and group them into cohorts of lower or higher risk for future COPD exacerbations. Proportions of patients in each group who did not receive medications recommended by COPD guidelines were determined. Generalized estimating equation modeling was used to determine associations between patient and physician factors and nonreceipt of recommended medications.Results: About 54% and 88% of people with COPD received sufficient recommended medications in the low and high risk of exacerbation groups, respectively. Longer duration of COPD, higher comorbidity, dementia, and older physician age were associated with nonreceipt of recommended medications in both groups. People who had a co-diagnosis of asthma, who received care by a pulmonologist and who received spirometry were more likely to receive recommended medication.Interpretation: COPD medications seem underused by the COPD population, and various factors are associated with suboptimal receipt. Targeting these factors would help improve the care and health of people with COPD. [ABSTRACT FROM AUTHOR]

Background: Infant pulmonary function tests (iPFTs) in subjects with neuroendocrine cell hyperplasia of infancy (NEHI) have demonstrated substantial expiratory airflow obstruction and air trapping.Research Question: Can indices from iPFTs be used in the diagnosis of NEHI?Study Design and Methods: This is an observational case-control study evaluating iPFT results from a registry of patients assessed at the Hadassah Hebrew University Medical Center between 2008 and 2018. iPFTs results in infants with NEHI were compared to two disease control infant groups (infants evaluated for recurrent wheezing and infants evaluated due to prematurity) and a spirometry control group of infants with normal expiratory airflow, using the Kruskal-Wallis test. Receiver operating characteristic (ROC) curves were used to assess the diagnostic accuracy of iPFT indices.Results: We evaluated iPFT data in 481 infants (15, NEHI; 292, wheezing; 128, premature; and 46, spirometry control group). Infants with NEHI had significantly increased trapped air volumes (median functional residual capacity measured with infant whole-body plethysmography [FRCpleth] was 199% predicted; median ratio of residual volume to total lung capacity was 59% predicted) when compared with results in all evaluated groups of infants (P < .001), including multiple pairwise comparisons. Airflow limitation was demonstrated in infants with NEHI when compared with the infants in the spirometry control group but was similar to the two disease control groups. FRCpleth had the best discriminatory ability for NEHI diagnosis, with an FRCpleth ≥ 150% predicted demonstrating a ROC of 0.91 (95% CI, 0.82-1.00), sensitivity of 86.7% (95% CI, 59.5%-98.3%), and specificity of 95.5% (95% CI, 93.2%-97.3%).Interpretation: Findings on iPFTs of markedly increased air trapping, out of proportion to the degree of airflow limitation, are characteristic of infants with NEHI. iPFT results demonstrating an FRCpleth ≥ 150% predicted are highly specific for NEHI and may aid in early diagnosis. Further research is required to confirm these findings in a prospective cohort and to understand the pathophysiologic explanation for these findings. [ABSTRACT FROM AUTHOR]

Background: Attenuation of transforming growth factor β by blocking angiotensin II has been shown to reduce emphysema in a murine model. General population studies have demonstrated that the use of angiotensin converting enzyme inhibitors (ACEis) and angiotensin-receptor blockers (ARBs) is associated with reduction of emphysema progression in former smokers and that the use of ACEis is associated with reduction of FEV1 progression in current smokers.Research Question: Is use of ACEi and ARB associated with less progression of emphysema and FEV1 decline among individuals with COPD or baseline emphysema?Methods: Former and current smokers from the Genetic Epidemiology of COPD Study who attended baseline and 5-year follow-up visits, did not change smoking status, and underwent chest CT imaging were included. Adjusted linear mixed models were used to evaluate progression of adjusted lung density (ALD), percent emphysema (%total lung volume <-950 Hounsfield units [HU]), 15th percentile of the attenuation histogram (attenuation [in HU] below which 15% of voxels are situated plus 1,000 HU), and lung function decline over 5 years between ACEi and ARB users and nonusers in those with spirometry-confirmed COPD, as well as all participants and those with baseline emphysema. Effect modification by smoking status also was investigated.Results: Over 5 years of follow-up, compared with nonusers, ACEi and ARB users with COPD showed slower ALD progression (adjusted mean difference [aMD], 1.6; 95% CI, 0.34-2.9). Slowed lung function decline was not observed based on phase 1 medication (aMD of FEV1 % predicted, 0.83; 95% CI, -0.62 to 2.3), but was when analysis was limited to consistent ACEi and ARB users (aMD of FEV1 % predicted, 1.9; 95% CI, 0.14-3.6). No effect modification by smoking status was found for radiographic outcomes, and the lung function effect was more pronounced in former smokers. Results were similar among participants with baseline emphysema.Interpretation: Among participants with spirometry-confirmed COPD or baseline emphysema, ACEi and ARB use was associated with slower progression of emphysema and lung function decline.Trial Registry: ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

Background: Small airways obstruction (SAO) is common in general populations. It has been associated with respiratory symptoms, cardiometabolic diseases, and progression to COPD over time. Whether SAO predicts mortality is largely unknown., Research Question: Is spirometry-defined SAO associated with increased mortality?, Methods: Data were analyzed from 252,877 adult participants, aged 40 to 69 years at baseline, in the UK Biobank who had provided good-quality spirometry measurements. SAO was defined as the ratio of the forced expiratory volume in 3 s to the forced expiratory volume in 6 s less than the lower limit of normal. SAO was considered to be isolated if present when the FEV 1 /forced expiratory volume in 6 s ratio was normal (ie, greater than the lower limit of normal). A multivariable Cox regression model was used to assess the association of SAO, and isolated SAO, with all-cause and disease-specific mortality. Sex differences were investigated in these associations, and the primary analysis was repeated, excluding those who ever smoked. All models were adjusted for potential confounders such as sex, BMI, smoking status, smoking pack-years, assessment center, Townsend deprivation index, and ethnicity., Results: A total of 59,744 participants with SAO were identified, of whom 24,004 had isolated SAO. A total of 5,009 deaths were reported over a median of 12.8 years of follow-up. Participants with SAO had increased all-cause (hazard ratio [HR], 1.31; 95% CI, 1.26-1.36), cardiovascular (HR, 1.39; 95% CI, 1.29-1.51), respiratory (HR, 2.20; 95% CI, 1.92-2.51), and neoplasm (HR, 1.23; 95% CI, 1.17-1.29) mortality risk. These associations were not modified by sex. However, in those who never smoked, only respiratory and cardiovascular mortality risk was associated with SAO. Isolated SAO was also associated with an increased mortality risk (HR, 1.14; 95% CI, 1.07-1.20)., Interpretation: Individuals with SAO have an increased risk of all-cause and disease-specific mortality. Further studies are needed to determine whether SAO causes mortality or is a marker of underlying disease., Competing Interests: Financial/Nonfinancial Disclosures None declared., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Metabolic syndrome and insulin resistance are associated with worsened outcomes of chronic lung disease. The triglyceride-glucose index (TyG), a measure of metabolic dysfunction, is associated with metabolic syndrome and insulin resistance, but its relationship to lung health is unknown.Research Question: What is the relationship of TyG to respiratory symptoms, chronic lung disease, and lung function?Study Design and Methods: This study analyzed data from the National Health and Nutrition Examination Survey from 1999 to 2012. Participants included fasting adults age ≥ 40 years (N = 6,893) with lung function measurements in a subset (n = 3,383). Associations of TyG with respiratory symptoms (cough, phlegm production, wheeze, and exertional dyspnea), chronic lung disease (diagnosed asthma, chronic bronchitis, and emphysema), and lung function (FEV1, FVC, and obstructive or restrictive spirometry pattern) were evaluated, adjusting for sociodemographic variables, comorbidities, and smoking. TyG was compared vs insulin resistance, represented by the homeostatic model assessment of insulin resistance (HOMA-IR), and vs the metabolic syndrome.Results: TyG was moderately correlated with HOMA-IR (Spearman ρ = 0.51) and had good discrimination for metabolic syndrome (area under the receiver-operating characteristic curve, 0.80). A one-unit increase in TyG was associated with higher odds of cough (adjusted OR [aOR], 1.28; 95% CI, 1.06-1.54), phlegm production (aOR, 1.20; 95% CI, 1.01-1.43), wheeze (aOR, 1.18; 95% CI, 1.03-1.35), exertional dyspnea (aOR, 1.21; 95% CI, 1.07-1.38), and a diagnosis of chronic bronchitis (aOR, 1.21; 95% CI, 1.02-1.43). TyG was associated with higher relative risk of a restrictive spirometry pattern (adjusted relative risk ratio, 1.45; 95% CI, 1.11-1.90). Many associations were maintained with additional adjustment for HOMA-IR or metabolic syndrome.Interpretation: TyG was associated with respiratory symptoms, chronic bronchitis, and a restrictive spirometry pattern. Associations were not fully explained by insulin resistance or metabolic syndrome. TyG is a satisfactory measure of metabolic dysfunction with relevance to pulmonary outcomes. Prospective study to define TyG as a biomarker for impaired lung health is warranted. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In recent months, medical institutions across the United States redoubled their efforts to examine the history of race and racism in medicine, in classrooms, in research, and in clinical practice. In this essay, I explore the history of racialization of the spirometer, a widely used instrument in pulmonary medicine to diagnose respiratory diseases and to assess eligibility for compensation. Beginning with Thomas Jefferson, who first noted racial difference in what he referred to as "pulmonary dysfunction," to the current moment in clinical medicine, I interrogate the history of the idea of "correcting" for race and how researchers explained difference. To explore how race correction became normative, initially just for people labeled "black," I examine visible and invisible racialized processes in scientific practice. Over more than two centuries, as ideas of innate difference hardened, few questioned the conceptual underpinnings of race correction in medicine. At a moment when "race norming" is under investigation throughout medicine, it is essential to rethink race correction of spirometric measurements, whether enacted through the use of a correction factor or through the use of population-specific standards. Historical analysis is central to these efforts. [ABSTRACT FROM AUTHOR]

The clinical research we do to improve our understanding of disease and to develop new therapies has temporarily been delayed as the global health-care enterprise has focused its attention on those impacted by coronavirus disease 2019 (COVID-19). Although rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are decreasing in many areas, many locations continue to have a high prevalence of infection. Nonetheless, research must continue and institutions are considering approaches to restarting non-COVID-related clinical investigation. Those restarting respiratory research must navigate the added planning challenges that take into account outcome measures that require aerosol-generating procedures. Such procedures potentially increase risk of transmission of SARS-CoV-2 to research staff, use limited personal protective equipment, and require conduct in negative-pressure rooms. One must also be prepared to address the potential for COVID-19 resurgence. With research subject and staff safety and maintenance of clinical trial data integrity as the guiding principles, here we review key considerations and suggest a step-wise approach for resuming respiratory clinical research. [ABSTRACT FROM AUTHOR]

Background: COPD is associated with nighttime respiratory symptoms, poor sleep quality, and increased risk of nocturnal death. Overnight deterioration of inspiratory capacity (IC) and FEV1 have been documented previously. However, the precise nature of this deterioration and mechanisms by which evening bronchodilation may mitigate this occurrence have not been studied.Research Question: What is the effect of evening dosing of dual, long-acting bronchodilation on detailed nocturnal respiratory mechanics and inspiratory neural drive (IND)?Study Design and Methods: A double-blind, randomized, placebo-controlled crossover study assessed the effects of evening long-acting bronchodilation (aclidinium bromide/formoterol fumarate dihydrate: 400/12 μg) or placebo on morning trough IC (12 h after the dose; primary outcome) and serial overnight measurements of spirometry, dynamic respiratory mechanics, and IND (secondary outcomes). Twenty participants with COPD (moderate/severe airway obstruction and lung hyperinflation) underwent serial measurements of IC, spirometry, breathing pattern, esophageal and transdiaphragmatic pressures, and diaphragm electromyography (diaphragmatic electromyography as a percentage of maximum; IND) at 6 time points from 0 to 12 h after the dose and compared with sleeping IND.Results: Compared with placebo, evening bronchodilation was not associated with increased morning trough IC 12 h after the dose (P = .48); however, nadir IC (lowest IC, independent of time), peak IC, area under the curve for 12 h after the dose, and IC for 10 h after the dose were improved (P < .05). During placebo, total airways resistance, lung hyperinflation, IND, and tidal esophageal and transdiaphragmatic pressure swings all increased significantly overnight compared with baseline evening values; however, each of these parameters improved with bronchodilator treatment (P < .05) with no change in ventilation or breathing pattern.Interpretation: Respiratory mechanics significantly deteriorated at night during placebo. Although the morning trough IC was unchanged, evening bronchodilator treatment was associated consistently with sustained overnight improvements in dynamic respiratory mechanics and inspiratory neural drive compared with placebo CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02429765. [ABSTRACT FROM AUTHOR]

Background: In cohort studies of pulmonary sarcoidosis, abnormal ventilatory patterns have generally been subdivided into restrictive and obstructive defects. Mixed ventilatory defects have largely been overlooked in pulmonary sarcoidosis, as total lung capacity has seldom been taken into account in historical series.Research Question: This study evaluated the prevalence of mixed disease in pulmonary sarcoidosis and its clinical associations.Study Design and Methods: In patients with pulmonary sarcoidosis (N = 1,110), mixed defects were defined according to American Thoracic Society/European Respiratory Society criteria. Clinical data, pulmonary function variables, and vital status were abstracted from clinical records. Chest radiographs were evaluated independently by two experienced radiologists.Results: The prevalence of a mixed ventilatory defect was 10.4% in the whole cohort, rising to 25.9% in patients with airflow obstruction. Compared with isolated airflow obstruction, mixed defects were associated with lower diffusing lung capacity for carbon monoxide levels (50.7 ± 16.3 vs 70.8 ± 18.1; P < .0001), a higher prevalence of chest radiographic stage IV disease (63.5% vs 38.3%; P < .0001), and higher mortality (hazard ratio, 2.36; 95% CI, 1.34-4.15; P = .003). These findings were reproduced in all patient subgroup analyses, including patients with a histologic diagnosis, a clinical diagnosis, incident disease, and prevalent disease.Interpretation: Mixed disease is present in approximately 25% of patients with pulmonary sarcoidosis and airflow obstruction and is associated with lower diffusing lung capacity for carbon monoxide levels, a higher prevalence of stage IV disease, and higher mortality than seen in a pure obstructive defect. These observations identify a distinct phenotype associated with a mixed ventilatory defect, justifying future studies of its clinical and pathogenetic significance. [ABSTRACT FROM AUTHOR]

Background: Inequitable access to quality health care contributes to the known poorer outcomes of people living in regional/remote areas (compared with urban-based), especially for First Nations people. Integration of specialist outreach services within primary care is one strategy that can reduce the inequity when modeled to the needs and available resources of target communities.Research Question: To evaluate whether respiratory outreach clinics in regional and remote Queensland are as effective as tertiary respiratory services at improving the lung function of children.Study Design and Methods: From existing databases, we obtained spirometry data of children (aged 3-18 years) seen at Indigenous-focused outreach clinics in regional and remote Queensland and Brisbane-based pediatric tertiary hospitals over the same contemporary period (October 2010 to July 2019). We compared the change in spirometry z scores (Δz) at follow-up for both groups of children.Results: Lung function significantly improved in both groups: Tertiary hospital (n = 2,249; ΔzFEV1 = 0.22, 95% CI, 0.17 to 0.27; ΔzFVC = 0.23, 95% CI, 0.18 to 0.28); outreach (n = 252; ΔzFEV1 = 0.35, 95% CI, 0.22 to 0.48; ΔzFVC = 0.36, 95% CI, 0.23 to 0.50). No significant intergroup differences were found in ΔzFEV1 (0.13; 95%CI, -0.02 to 0.28; P = .10) or ΔzFVC (0.14; 95% CI, -0.02 to 0.29; P = .08) improvement from baseline. In both groups, the proportion of children with zFEV1 > 0 at follow-up (hospital = 31.7%; outreach = 46.8%) significantly increased (hospital P = .001; outreach P = .009) from baseline (hospital = 27.2%; outreach = 35.3%). Numbers of children with zFEV1 > 0 significantly increased for asthma and bronchiectasis outreach subgroups, and for children with asthma in the hospital-based group.Interpretation: Comparable significant lung function improvement of children was seen in Indigenous-focused outreach remote/regional clinics and paediatric tertiary hospitals. This suggests that effective clinical care is achievable within the outreach setting. [ABSTRACT FROM AUTHOR]

Background: In patients with a history suggestive of asthma, diagnosis is usually confirmed by spirometry with bronchodilator response (BDR) or confirmatory methacholine challenge testing (MCT).Research Question: We examined the proportion of participants with negative BDR testing who had a positive MCT (and its predictors) result and characteristics of MCT, including effects of controller medication tapering and temporal variability (and predictors of MCT result change), and concordance between MCT and pulmonologist asthma diagnosis.Study Design and Methods: Adults with self-reported physician-diagnosed asthma were recruited by random-digit dialing across Canada. Subjects performed spirometry with BDR testing and returned for MCT if testing was nondiagnostic for asthma. Subjects on controllers underwent medication tapering with serial MCTs over 3 to 6 weeks. Subjects with a negative MCT (the provocative concentration of methacholine that results in a 20% drop in FEV1 [PC20] > 8 mg/mL) off medications were examined by a pulmonologist and had serial MCTs after 6 and 12 months.Results: Of 500 subjects (50.5 ± 16.6 years old, 68.0% female) with a negative BDR test for asthma, 215 (43.0%) had a positive MCT. Subjects with prebronchodilator airflow limitation were more likely to have a positive MCT (OR, 1.90; 95% CI, 1.17-3.04). MCT converted from negative to positive, with medication tapering in 18 of 94 (19.1%) participants, and spontaneously over time in 25 of 165 (15.2%) participants. Of 231 subjects with negative MCT, 28 (12.1%) subsequently received an asthma diagnosis from a pulmonologist.Interpretation: In subjects with a self-reported physician diagnosis of asthma, absence of bronchodilator reversibility had a negative predictive value of only 57% to exclude asthma. A finding of spirometric airflow limitation significantly increased chances of asthma. MCT results varied with medication taper and over time, and pulmonologists were sometimes prepared to give a clinical diagnosis of asthma despite negative MCT. Correspondingly, in patients for whom a high clinical suspicion of asthma exists, repeat testing appears to be warranted. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

FVC z score: normal EM vs IDA/CA/MTD: P =.012; ODA vs IDA/CA/MTD: P =.009; ODA/IDA vs IDA/CA/MTD: P =.046. FEV SB 1 sb /FVC z score: normal EM vs IDA/CA/MTD: P =.001; ODA/IDA vs IDA/CA/MTD: P =.020; ODA vs IDA/CA/MTD: P =.047. IDA/CA/MTD vs ODA/IDA: P =.036; CCDC39 and CCDC40 vs DNAH5: P <.0001; CCDC39 and CCDC40 vs DNAH11: P <.0001; PsA infection vs other infection: P =.0002; PsA infection vs uninfected: P <.0001; other infections vs uninfected: P = not significant. [Extracted from the article]

Background: The role and impact of chronic cough in individuals with COPD have not been described in the general population. This study hypothesized that comorbid chronic cough is a marker of disease severity in individuals with COPD.Methods: This study identified individuals with COPD and chronic cough, and recorded respiratory symptoms, health-care utilizations, lung function, and inflammatory biomarkers in blood in a nested cohort of 43,271 adults from the Copenhagen General Population Study (CGPS).Results: Among 43,271 individuals from the general population, 8,181 (19%) experienced COPD, of whom 796 (10%) had chronic cough. Individuals with COPD and chronic cough had a Leicester Cough Questionnaire median (25th-75th percentiles) total score of 17.7 (16.0-18.9), corresponding to 5.9 (5.3-6.3) for the physical domain, 5.6 (4.9-6.3) for the psychological domain, and 6.3 (5.8-6.8) for the social domain. Among individuals with COPD, those with chronic cough vs those without chronic cough more often experienced sputum production (60% vs 8%), wheezing (46% vs 14%), dyspnea (66% vs 38%), chest pain/tightness (9% vs 4%), nighttime dyspnea (8% vs 3%), episodes of acute bronchitis/pneumonias in the last 10 years (45% vs 25%), and ≥ 3 general practitioner visits in the past 12 months (53% vs 37%). Furthermore, these individuals had lower FEV1 % predicted (81% vs 89%) and FEV1/FVC (0.64 vs 0.66), as well as higher levels of high-sensitivity C-reactive protein, fibrinogen, leukocytes, neutrophils, eosinophils, and IgE in blood.Conclusions: Comorbid chronic cough in individuals with COPD is associated with a more severe disease in terms of more respiratory symptoms and health-care utilizations, lower lung function, and increased inflammation in blood. [ABSTRACT FROM AUTHOR]

Background: Persistent bronchodilator response (BDR) following diagnosis of asthma is an underrecognized treatable trait, associated with worse lung function and asthma control. The forced oscillation technique (FOT) measures respiratory system impedance, and BDR cutoffs have been proposed for healthy adults; however, the relevance in asthma is unknown. We compared BDR cutoffs, using FOT and spirometry, in asthma and the relationship with asthma control.Methods: Data from patients with asthma who withheld bronchodilator medication for at least 8 h before a tertiary airway clinic visit were reviewed. All subjects performed FOT and spirometry before and after salbutamol administration, and completed the Asthma Control Test. FOT parameters examined included respiratory system resistance (R5) and reactance (X5) at 5 Hz, and area under the reactance curve (AX). BDR was defined by standard recommendations for spirometry and based on the 95th percentile of BDR in healthy adults for FOT.Results: Fifty-two subjects (18 men; mean age, 53 ± 18 years) were included. BDR was identified more frequently by FOT than spirometry (54% vs 27% of subjects). BDR assessed by X5 and AX, but not R5, was associated with spirometric BDR (χ2, P < .01) and correlated with asthma control (X5: rs = -0.36, P < .01; AX: rs = 0.34, P = .01). BDR measured by reactance parameters identified more subjects with poor asthma control than did spirometry (AX, 69% vs spirometry, 41%).Conclusions: BDR assessed by FOT can identify poor asthma control. Reactance parameters were more sensitive in identifying poor asthma control than spirometry, supporting the use of FOT to complement spirometry in the clinical management of asthma. [ABSTRACT FROM AUTHOR]

Background: Heroin smokers have high rates of COPD, respiratory morbidity, hospital admission, and mortality. We assessed the natural history of symptoms and lung function in this population over time.Methods: A cohort of heroin smokers with COPD was followed for 18 to 24 months. At baseline and follow-up, respiratory symptoms were measured by the Medical Research Council Dyspnea Scale (MRC) and the COPD Assessment Tool (CAT), and postbronchodilator spirometry was performed. Frequency of health-care-seeking episodes was extracted from routine health records. Parametric, nonparametric, and linear regression models were used to analyze the change in symptoms and lung function over time.Results: Of 372 participants originally recruited, 161 were assessed at follow-up (mean age, 51.0 ± 5.3 years; 74 women [46%]) and 106 participants completed postbronchodilator spirometry. All participants were current or previous heroin smokers, and 122 (75.8%) had smoked crack. Symptoms increased over time (MRC score increased by 0.48 points per year, P < .001; CAT score increased by 1.60 points per year, P < .001). FEV1 declined annually by 90 ± 190 mL (P < .001). This deterioration was not associated with change in tobacco or heroin smoking status or use of inhaled medications.Conclusions: Heroin smokers experience a high and increasing burden of chronic respiratory symptoms and a decline in FEV1 that exceeds the normal age-related decline observed among tobacco smokers with COPD and healthy nonsmokers. Targeted COPD diagnostic and treatment services hosted within opiate substitution services could benefit this vulnerable, relatively inaccessible, and underserved group of people. [ABSTRACT FROM AUTHOR]

Background: Prediction of future lung function will enable the identification of individuals at high risk of developing COPD, but the trajectory of lung function decline varies greatly among individuals. This study involved the development and validation of an individualized prediction model of lung function trajectory and risk of airflow limitation in the general population.Methods: Data were obtained from the Framingham Offspring Cohort, which included 4,167 participants ≥ 20 years of age and who had ≥ 2 valid spirometry assessments. The primary outcome was prebronchodilator FEV1; the secondary outcome was the risk of airflow limitation (defined as FEV1/FVC less than the lower limit of normal). Mixed effects regression models were developed for individualized prediction, and a machine learning algorithm was used to determine essential predictors. The model was validated in two large, independent multicenter cohorts (N = 2,075 and 12,913, respectively).Results: With 20 common predictors, the model explained 79% of the variation in FEV1 decline in the derivation cohort. In two validation datasets, the model had low error in predicting FEV1 decline (root mean square error range, 0.18-0.22 L) and high discriminative power in predicting risk of airflow limitation (C-statistic range, 0.86-0.87). This model was implemented in a freely accessible website-based application, which allows prediction based on flexible sets of predictors (http://resp.core.ubc.ca/ipress/FraminghamFEV1).Conclusions: The individualized predictor is an accurate tool to predict long-term lung function trajectories and risk of airflow limitation in the general population. This model enables identifying individuals at higher risk of COPD, who can then be targeted for preventive therapies. [ABSTRACT FROM AUTHOR]

Background: The respiratory duty cycle (Ti/Ttot) can influence bronchoprovocation test results and nebulized drug delivery. The Ti/Ttot has not yet been examined in individuals with airway hyperresponsiveness (AHR) in typical bronchoprovocation test conditions. This study investigated the mean Ti/Ttot in participants with and without AHR and whether the Ti/Ttot changes with increasing bronchoconstriction.Methods: Fifteen participants with AHR and fifteen participants without AHR completed this randomized crossover study. An ultrasonic spirometer was used for continuous measurement of the Ti/Ttot as participants inhaled room air or aerosolized solution. Each participant completed two methacholine challenges, one using a continuous-output vibrating mesh nebulizer/ultrasonic spirometer and one with the nebulizer only. Prior to each methacholine challenge, participants inhaled room air and aerosolized saline through the nebulizer/spirometer setup to record baseline Ti/Ttot data.Results: The mean Ti/Ttot findings [95% CIs] during room air inhalation were 0.392 [0.378-0.406] and 0.447 [0.426-0.468] in participants with and without AHR, respectively (P < .001). The mean Ti/Ttot during saline inhalation were 0.389 [0.373-0.405] and 0.424 [0.398-0.450] in participants with and without AHR (P = .040). The Ti/Ttot showed a nonsignificant downward trend with progressive methacholine-induced bronchoconstriction.Conclusions: The mean Ti/Ttot in participants with AHR closely resembles the assumed Ti/Ttot of 0.40 recommended for standard use when calculating methacholine challenge results. Since the Ti/Ttot did not change significantly over the course of a methacholine challenge, the same Ti/Ttot can be used to calculate the dose of methacholine inhaled, regardless of the level of bronchoconstriction.Trial Registry: ClinicalTrials.gov; No.: NCT03505489; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]