Chronic Obstructive Pulmonary Disease Genetic Epidemiology Research Articles

Race-Specific Spirometry Equations Do Not Improve Models of Dyspnea and Quantitative Chest CT Phenotypes

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 FEV1 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 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. 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.

Associations Between Muscle Weakness and Clinical Outcomes in Current and Former Smokers.

Smokers with chronic obstructive pulmonary disease (COPD) are at increased risk of muscle weakness. There are limited data describing weakness in smokers with normal spirometry and preserved ratio-impaired spirometry (PRISm), 2 subgroups at risk of respiratory symptom burden and activity limitations. In this study, we evaluated the associations of 2 weakness measures, sit-to-stand (STS) and handgrip strength (HGS), with clinical outcomes in smokers with COPD, normal spirometry, and PRISm. We evaluated 1972 current and former smokers from the COPD Genetic Epidemiology (COPDGene®) cohort with STS and HGS measurements at their 10-year study visit. Multivariable regression modeling was used to assess associations between weakness measures and the 6-minute walk distance (6MWD) test, the St George's Respiratory Questionnaire (SGRQ), the Short-Form-36 (SF-36), severe exacerbations, and prospective mortality, reported as standardized coefficients (β), odds ratios (ORs), or hazard ratios (HRs). Compared with HGS, STS was more strongly associated with the 6MWD (β=0.45, p<0.001 versus. β=0.25, p<0.001), SGRQ (β=-0.24, p<0.001 versus β=-0.18, p<0.001), SF-36 Physical Functioning (β=0.36, p<0.001 versus β=0.25, p<0.001), severe exacerbations (OR 0.95, p=0.04 versus OR 0.97, p=0.01), and prospective mortality (HR 0.83, p=0.001 versus HR 0.94, p=0.03). Correlations remained after stratification by spirometric subgroups. Compared with males, females had larger magnitude effect sizes between STS and clinical outcomes. STS and HGS are easy to perform weakness measures that provide important information about functional performance, health-related quality of life, severe exacerbations, and survival in smokers, regardless of spirometric subgroup. This iterates the importance of screening current and former smokers for weakness in the outpatient setting.

Changes in Lung Volumes with Spirometric Disease Progression in COPD.

Abnormal lung volumes representing air trapping identify the subset of smokers with preserved spirometry who develop spirometric chronic obstructive pulmonary disease (COPD) and adverse outcomes. However, how lung volumes evolve in early COPD as airflow obstruction develops remains unclear. To establish how lung volumes change with the development of spirometric COPD, we examined lung volumes from the pulmonary function data (seated posture) available in the U.S. Department of Veterans Affairs electronic health records (n=71,356) and lung volumes measured by computed tomography (supine posture) available from the COPD Genetic Epidemiology (COPDGene®) study (n=7969) and the SubPopulations and InterMediate Outcome Measures In COPD Study (SPIROMICS) (n=2552) cohorts, and studied their cross-sectional distributions and longitudinal changes across the airflow obstruction spectrum. Patients with preserved ratio-impaired spirometry (PRISm) were excluded from this analysis. Lung volumes from all 3 cohorts showed similar patterns of distributions and longitudinal changes with worsening airflow obstruction. The distributions for total lung capacity (TLC), vital capacity (VC), and inspiratory capacity (IC) and their patterns of change were nonlinear and included different phases. When stratified by airflow obstruction using Global initiative for chronic Obstructive Lung Disease (GOLD) stages, patients with GOLD 1 (mild) COPD had larger lung volumes (TLC, VC, IC) compared to patients with GOLD 0 (smokers with preserved spirometry) or GOLD 2 (moderate) disease. In longitudinal follow-up of baseline GOLD 0 patients who progressed to spirometric COPD, those with an initially higher TLC and VC developed mild obstruction (GOLD 1) while those with an initially lower TLC and VC developed moderate obstruction (GOLD 2). In COPD, TLC, and VC have biphasic distributions, change in nonlinear fashions as obstruction worsens, and could differentiate those GOLD 0 patients at risk for more rapid spirometric disease progression.

Suspected Interstitial Lung Disease in COPDGene Study.

Rationale: Although interstitial lung abnormalities (ILA), specific patterns of incidentally-detected abnormal density on computed tomography, have been associated with abnormal lung function and increased mortality, it is unclear if a subset with incidental interstitial lung disease (ILD) accounts for these adverse consequences. Objectives: To define the prevalence and risk factors of suspected ILD and assess outcomes. Methods: Suspected ILD was evaluated in the COPDGene (Chronic Obstructive Pulmonary Disease Genetic Epidemiology) study, defined as ILA and at least one additional criterion: definite fibrosis on computed tomography, FVC less than 80% predicted, or DLCO less than 70% predicted. Multivariable linear, longitudinal, and Cox proportional hazards regression models were used to assess associations with St. George's Respiratory Questionnaire, 6-minute-walk test, supplemental oxygen use, respiratory exacerbations, and mortality. Measurements and Main Results: Of 4,361 participants with available data, 239 (5%) had evidence for suspected ILD, whereas 204 (5%) had ILA without suspected ILD. In multivariable analyses, suspected ILD was associated with increased St. George's Respiratory Questionnaire score (mean difference [MD], 3.9 points; 95% confidence interval [CI], 0.6-7.1; P = 0.02), reduced 6-minute-walk test (MD, -35 m; 95% CI, -56 m to -13 m; P = 0.002), greater supplemental oxygen use (odds ratio [OR], 2.3; 95% CI, 1.1-5.1; P = 0.03) and severe respiratory exacerbations (OR, 2.9; 95% CI, 1.1-7.5; P = 0.03), and higher mortality (hazard ratio, 2.4; 95% CI, 1.2-4.6; P = 0.01) compared with ILA without suspected ILD. Risk factors associated with suspected ILD included self-identified Black race (OR, 2.0; 95% CI, 1.1-3.3; P = 0.01) and pack-years smoking history (OR, 1.2; 95% CI, 1.1-1.3; P = 0.0005). Conclusions: Suspected ILD is present in half of those with ILA in COPDGene and is associated with exercise decrements and increased symptoms, supplemental oxygen use, severe respiratory exacerbations, and mortality.

185-LB: Pulmonary Function and Diabetes Risk in a Cohort of Black and White Current and Former Smokers

The recent COVID-19 pandemic, which saw an increased risk of subsequent diabetes among persons with COVID-19 as well as greater casualties among persons with diabetes, has brought renewed attention to the role of lung function in diabetes. We tested the relationship of lung function and chronic obstructive pulmonary disease (COPD) with diabetes in a population of current and former smokers. Using data from the COPD Genetic Epidemiology (COPDGene) cohort, we conducted a diabetes follow-up (2012-2018) of a cohort of Black and White current and former smokers with (n=2442) and w/out (n=2214) COPD, aged 39-85 years and w/out diabetes at cohort entry. Lung function was modeled using Forced Expiratory Volume at 1 second % predicted (FEV1%P) . COPD was defined as the ratio of FEV1% to FVC% &amp;lt;0.7. Logistic regression was used to compute ORs (95% CIs) for risk of incident diabetes. The incidence of diabetes was 8% over the five years of follow-up, representing a 43% increase in prevalence. After controlling for age, sex, and race, COPD at baseline was a significant risk factor for diabetes (OR=1.51, 1.21-1.88) . Significant interaction existed between baseline COPD and baseline Fev1%p (p-interaction=0.01) , such that Fev1%p only predicted diabetes among those w/out (OR=0.98, 0.96-0.99) but not among those with COPD at baseline (OR=0.99, 0.99-1.00) . Upon stratification by race, Fev1%p was a significant predictor among Blacks but not Whites, but effect modification by race was not observed. Blacks were at twice the risk of diabetes overall (OR=2.04, 1.59-2.60) and were at 3 times the risk among those w/out COPD (OR=2.91, 1.98-4.27) . BMI increased risk in both races regardless of COPD status; however, a higher BMI was a stronger risk factor for diabetes among Whites than Blacks, particularly for those with baseline COPD (race*BMI interaction p=0.06) . In this large population of current and former smokers, our data suggest that lower lung function prior to the development of COPD is a risk factor for diabetes, particularly among Blacks. BMI is an important risk factor in both races, but appears to play a stronger role among Whites. Disclosure R. B. Conway: None. K. Young: None. Y. Li: Employee; Vertex Pharmaceuticals Incorporated. E. Austin: None. G. L. Kinney: None. Funding National Institutes of Health (U01HL089897)

Automated CT Staging of Chronic Obstructive Pulmonary Disease Severity for Predicting Disease Progression and Mortality with a Deep Learning Convolutional Neural Network

To develop a deep learning-based algorithm to stage the severity of chronic obstructive pulmonary disease (COPD) through quantification of emphysema and air trapping on CT images and to assess the ability of the proposed stages to prognosticate 5-year progression and mortality. In this retrospective study, an algorithm using co-registration and lung segmentation was developed in-house to automate quantification of emphysema and air trapping from inspiratory and expiratory CT images. The algorithm was then tested in a separate group of 8951 patients from the COPD Genetic Epidemiology study (date range, 2007-2017). With measurements of emphysema and air trapping, bivariable thresholds were determined to define CT stages of severity (mild, moderate, severe, and very severe) and were evaluated for their ability to prognosticate disease progression and mortality using logistic regression and Cox regression. On the basis of CT stages, the odds of disease progression were greatest among patients with very severe disease (odds ratio [OR], 2.67; 95% CI: 2.02, 3.53; P < .001) and were elevated in patients with moderate disease (OR, 1.50; 95% CI: 1.22, 1.84; P = .001). The hazard ratio of mortality for very severe disease at CT was 2.23 times the normal ratio (95% CI: 1.93, 2.58; P < .001). When combined with Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging, patients with GOLD stage 2 disease had the greatest odds of disease progression when the CT stage was severe (OR, 4.48; 95% CI: 3.18, 6.31; P < .001) or very severe (OR, 4.72; 95% CI: 3.13, 7.13; P < .001). Automated CT algorithms can facilitate staging of COPD severity, have diagnostic performance comparable with that of spirometric GOLD staging, and provide further prognostic value when used in conjunction with GOLD staging.Supplemental material is available for this article.© RSNA, 2021See also commentary by Kalra and Ebrahimian in this issue.

The Heterogeneity of COPD Patients in a Community-Based Practice and the Inadequacy of the Global Initiative for Chronic Obstructive Lung Disease Criteria: A Real-World Experience.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease with differing clinical presentations, which range from an asymptomatic obstructive defect on spirometry to symptomatic normal spirometry. The current standard for diagnosis requires exposure history and the presence of an obstructive ventilatory defect (forced expiratory volume in 1 second [FEV1] to forced vital capacity [FVC] ratio < 70%) on spirometry. In this real-world study, we analyzed patients with physician-diagnosed COPD, described their characteristics, and evaluated the diagnostic sensitivity of Global initiative for chronic Obstructive Lung Disease (GOLD) criteria in this population. We retrospectively analyzed the charts of 2115 patients for eligibility. A total of 1224 patients with physician-diagnosed COPD were selected for this study. The average age was 68.4±11.5 years, with 51% being female. Of the 1224 patients, 18% did not have a history of smoking, 73% had bronchodilator testing, and a significant response of ≥12% was noted in 23% of the COPD patients. Moreover, 43% of the patients met the GOLD criteria for the diagnosis of COPD, whereas the Global Lung Function Initiative (GLI) and lower limit of normal (LLN)criteria were only able to identify 26%. COPD-related mortality is continuing to rise, and it is currently ranked as the third leading cause of death, globally, after cardiovascular diseases and strokes. Despite this alarming statistic, COPD diagnosis is delayed in most cases and can remain undiagnosed, even in smokers. This is partly due to the restrictive GOLD diagnostic criteria, which requires the presence of FEV1/FVC ratio<70. The recently proposed COPD Genetic Epidemiology (COPDGene®) 2019 definition for COPD will improve and enhance our ability to diagnose COPD earlier and more accurately.

Progression of Emphysema and Small Airways Disease in Cigarette Smokers.

Little is known about factors associated with emphysema progression in cigarette smokers. We evaluated factors associated with change in emphysema and forced expiratory volume in 1 second (FEV1) in participants with and without chronic obstructive pulmonary disease (COPD). This retrospective study included individuals participating in the COPD Genetic Epidemiology study who completed the 5-year follow-up, including inspiratory and expiratory computed tomography (CT) and spirometry. All paired CT scans were analyzed using micro-mapping, which classifies individual voxels as emphysema or functional small airway disease (fSAD). Presence and progression of emphysema and FEV1 were determined based on comparison to nonsmoker values. Logistic regression analyses were used to identify clinical parameters associated with disease progression. A total of 3088 participants were included with a mean ± SD age of 60.7±8.9 years, including 72 nonsmokers. In all Global initiative for chronic Obstructive Lung Disease (GOLD) stages, the presence of emphysema at baseline was associated with emphysema progression (odds ratio [OR]: GOLD 0: 4.32; preserved ratio-impaired spirometry [PRISm]; 5.73; GOLD 1: 5.16; GOLD 2: 5.69; GOLD 3/4: 5.55; all p ≤0.01). If there was no emphysema at baseline, the amount of fSAD at baseline was associated with emphysema progression (OR for 1% increase: GOLD 0: 1.06; PRISm: 1.20; GOLD 1: 1.7; GOLD 3/4: 1.08; all p ≤ 0.03).In 1735 participants without spirometric COPD, progression in emphysema occurred in 105 (6.1%) participants and only 21 (1.2%) had progression in both emphysema and FEV1. The presence of emphysema is an important predictor of emphysema progression. In patients without emphysema, fSAD is associated with the development of emphysema. In participants without spirometric COPD, emphysema progression occurred independently of FEV1 decline.

Chronic Bronchitis in COPD Patients Creates Worse Symptom Burden Regardless of the Presence of Bronchiectasis in the COPDGene Cohort.

To assess whether the presence or absence of bronchiectasis has an impact on the patient-reported symptoms of chronic obstructive pulmonary disease (COPD) patients. The study included participants from the COPD Genetic Epidemiology Study (COPDGene®) cohort with available high-resolution chest tomography reporting the presence or absence of bronchiectasis (BE+/BE-) and survey data reporting the presence or absence of chronic bronchitis symptoms (CB+/CB-). Patient symptoms based on the St George's Respiratory Questionnaire (SGRQ) were then compared for the different groups. The study population included 7976 participants, mean age 60, Global initiative for chronic Obstructive Lung Disease (GOLD) stages 0 to 4, 18.8% BE+, and 19.5% CB+. The presence or absence of radiographic bronchiectasis was not associated with higher frequency of chronic bronchitis (GOLD 0 group odds ratio [OR] 1.01 [0.78,1.31], GOLD 1-2 group OR 1.19 [0.95, 1.50], GOLD 3-4 group OR 1.26 [0.99, 1.60]). Similarly, CB+ participants had higher SGRQ scores than CB- participants regardless of the presence of BE. Across all GOLD stages, chronic bronchitis symptoms are associated with worse pulmonary symptoms and significant impairment in quality of life. For patients with chronic bronchitis, the presence or absence of bronchiectasis is not associated with a significant difference in SGRQ symptom scores. Symptoms of chronic bronchitis impose a heavy burden on patients and should be treated regardless of the presence or absence of underlying bronchiectasis.

Impact of a Medical Diagnosis on Decision to Stop Smoking and Successful Smoking Cessation.

Smoking cessation counseling is a central part of the Medicare guidelines for lung cancer screening. With increasing age, many heavy smokers eventually stop smoking, however, factors influencing the decision to stop smoking are poorly understood. We postulated that declining health or physician-diagnosis of a medical condition may be associated with successful smoking cessation. A total of 4448 current and former smokers in Phase 2 of the COPD Genetic Epidemiology (COPDGene®) study answered a question about reasons for stopping smoking. Participants were classified as successful quitters (n=3345), and unsuccessful quitters (n=1003). Reasons cited for quitting were grouped as: medical diagnoses, social factors, symptoms. Logistic modeling of factors associated with successful quitting were adjusted for age, gender, race, and education. The most common factors cited for a quit attempt by all respondents were medical diagnoses (48%), followed by social factors (47%), and respiratory symptoms (36%). Successful quitters were more likely to be older, male, and non-Hispanic White. An adjusted model found increased age, White race, education beyond high school, and male sex favored successful quitting while the cited medical diagnoses, social factors, and "other" reasons were associated with unsuccessful quitting. Fagerstrom Nicotine Dependence scores were ³ 5 in 54% of the unsuccessful group compared to 45% for successful quitters(p<0.0001) suggesting some increased nicotine dependence in the unsuccessful quitters. Medical diagnosis was the most common factor cited for considering a quit attempt by both successful and unsuccessful quitters; however, successful quitting was influenced by demographic factors and potentially the severity of nicotine dependence.

Disease Progression Modeling in Chronic Obstructive Pulmonary Disease.

Rationale: The decades-long progression of chronic obstructive pulmonary disease (COPD) renders identifying different trajectories of disease progression challenging.Objectives: To identify subtypes of patients with COPD with distinct longitudinal progression patterns using a novel machine-learning tool called "Subtype and Stage Inference" (SuStaIn) and to evaluate the utility of SuStaIn for patient stratification in COPD.Methods: We applied SuStaIn to cross-sectional computed tomography imaging markers in 3,698 Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1-4 patients and 3,479 controls from the COPDGene (COPD Genetic Epidemiology) study to identify subtypes of patients with COPD. We confirmed the identified subtypes and progression patterns using ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) data. We assessed the utility of SuStaIn for patient stratification by comparing SuStaIn subtypes and stages at baseline with longitudinal follow-up data.Measurements and Main Results: We identified two trajectories of disease progression in COPD: a "Tissue→Airway" subtype (n = 2,354, 70.4%), in which small airway dysfunction and emphysema precede large airway wall abnormalities, and an "Airway→Tissue" subtype (n = 988, 29.6%), in which large airway wall abnormalities precede emphysema and small airway dysfunction. Subtypes were reproducible in ECLIPSE. Baseline stage in both subtypes correlated with future FEV1/FVC decline (r = -0.16 [P < 0.001] in the Tissue→Airway group; r = -0.14 [P = 0.011] in the Airway→Tissue group). SuStaIn placed 30% of smokers with normal lung function at elevated stages, suggesting imaging changes consistent with early COPD. Individuals with early changes were 2.5 times more likely to meet COPD diagnostic criteria at follow-up.Conclusions: We demonstrate two distinct patterns of disease progression in COPD using SuStaIn, likely representing different endotypes. One third of healthy smokers have detectable imaging changes, suggesting a new biomarker of "early COPD."

Immunoglobulin E as a Biomarker for the Overlap of Atopic Asthma and Chronic Obstructive Pulmonary Disease.

Asthma-COPD overlap (ACO) is a common clinical syndrome, yet there is no single objective definition. We hypothesized that immunoglobulin E (IgE) measurements could be used to refine the definition of ACO. In baseline plasma samples from 2870 participants in the COPD Genetic Epidemiology (COPDGene®) study, we measured total IgE levels and specific IgE levels to 6 common allergens. Compared to usual chronic obstructive pulmonary disease (COPD), participants with ACO (based on self-report of asthma) had higher total IgE levels (median 67.0 versus 42.2 IU/ml) and more frequently had at least one positive specific IgE (43.5% versus 24.5%). We previously used a strict definition of ACO in participants with COPD, based on self-report of a doctor's diagnosis of asthma before age 40. This strict ACO definition was refined by the presence of atopy, determined by total IgE > 100 IU/ml or at least one positive specific IgE, as was the broader definition of ACO based on self-reported asthma history. Participants with all 3 ACO definitions were younger (mean age 60.0-61.3 years), were more commonly African American (36.8%-44.2%), had a higher exacerbation frequency (1.0-1.2 in the past year), and had more airway wall thickening on quantitative analysis of chest computed tomography (CT) scans. Among participants with ACO, 37%-46% did not have atopy; these individuals had more emphysema on chest CT scan. Based on associations with exacerbations and CT airway disease, IgE did not clearly improve the clinical definition of ACO. However, IgE measurements could be used to subdivide individuals with atopic and non-atopic ACO, who might have different biologic mechanisms and potential treatments.

A Risk Prediction Model for Mortality Among Smokers in the COPDGene® Study.

Risk factor identification is a proven strategy in advancing treatments and preventive therapy for many chronic conditions. Quantifying the impact of those risk factors on health outcomes can consolidate and focus efforts on individuals with specific high-risk profiles. Using multiple risk factors and longitudinal outcomes in 2 independent cohorts, we developed and validated a risk score model to predict mortality in current and former cigarette smokers. We obtained extensive data on current and former smokers from the COPD Genetic Epidemiology (COPDGene®) study at enrollment. Based on physician input and model goodness-of-fit measures, a subset of variables was selected to fit final Weibull survival models separately for men and women. Coefficients and predictors were translated into a point system, allowing for easy computation of mortality risk scores and probabilities. We then used the SubPopulations and InteRmediate Outcome Measures In COPD Study (SPIROMICS) cohort for external validation of our model. Of 9867 COPDGene participants with standard baseline data, 17.6% died over 10 years of follow-up, and 9074 of these participants had the full set of baseline predictors (standard plus 6-minute walk distance and computed tomography variables) available for full model fits. The average age of participants in the cohort was 60 for both men and women, and the average predicted 10-year mortality risk was 18% for women and 25% for men. Model time-integrated area under the receiver operating characteristic curve statistics demonstrated good predictive model accuracy (0.797 average), validated in the external cohort (0.756 average). Risk of mortality was impacted most by 6-minute walk distance, forced expiratory volume in 1 second and age, for both men and women. Current and former smokers exhibited a wide range of mortality risk over a 10- year period. Our models can identify higher risk individuals who can be targeted for interventions to reduce risk of mortality, for participants with or without chronic obstructive pulmonary disease (COPD) using current Global initiative for obstructive Lung Disease (GOLD) criteria.

The Association of Multiparity with Lung Function and Chronic Obstructive Pulmonary Disease-Related Phenotypes.

Apparent increased female susceptibility to chronic obstructive pulmonary disease (COPD) suggests sex hormones modulate disease pathogenesis. Little is known about associations between multiparity and lung function in smokers. We hypothesized that multiparity is associated with lung function and measures of emphysema and airway disease. Utilizing female participants from the 5-year follow up of the COPD Genetic Epidemiology (COPDGene®) study we performed multivariable linear regressions to assess the effect of multiparity and number of pregnancies on forced expiratory volume in 1 second (FEV1) percentage of predicted (% predicted), FEV1/forced vital capacity (FVC), percent emphysema on computed tomography (CT) scans, and Pi10, a measure of airway thickening. We sampled never smokers and those with lower smoking exposure from the National Health and Nutrition Examination Survey (NHANES) 2011-2012 dataset. We included 1820 participants from COPDGene® and 418 participants from NHANES (321 never smokers, 97 ever smokers). In COPDGene®, multiparity (beta coefficient [β] = -3.8, 95% confidence interval [CI]: [-6.5, -1.1], p = 0.005) and higher number of pregnancies were associated with lower FEV1 % predicted. Multiparity was not associated with percent emphysema or Pi10. In individuals with no or mild obstruction, multiparity was associated with lower FEV1 % predicted. There was an interaction with multiparity and age on FEV1 % predicted (p = 0.025). In NHANES, there was no association between multiparity and FEV1 % predicted in never smokers or the lower smoking exposure group. Multiparity was associated with lower FEV1 % predicted in current and former smokers in COPDGene® study participants. These preliminary results emphasize the importance of smoking abstinence in women of child-bearing age.

COPDGene® 2019: Redefining the Diagnosis of Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) remains a major cause of morbidity and mortality. Present-day diagnostic criteria are largely based solely on spirometric criteria. Accumulating evidence has identified a substantial number of individuals without spirometric evidence of COPD who suffer from respiratory symptoms and/or increased morbidity and mortality. There is a clear need for an expanded definition of COPD that is linked to physiologic, structural (computed tomography [CT]) and clinical evidence of disease. Using data from the COPD Genetic Epidemiology study (COPDGene®), we hypothesized that an integrated approach that includes environmental exposure, clinical symptoms, chest CT imaging and spirometry better defines disease and captures the likelihood of progression of respiratory obstruction and mortality. Four key disease characteristics - environmental exposure (cigarette smoking), clinical symptoms (dyspnea and/or chronic bronchitis), chest CT imaging abnormalities (emphysema, gas trapping and/or airway wall thickening), and abnormal spirometry - were evaluated in a group of 8784 current and former smokers who were participants in COPDGene® Phase 1. Using these 4 disease characteristics, 8 categories of participants were identified and evaluated for odds of spirometric disease progression (FEV1 > 350 ml loss over 5 years), and the hazard ratio for all-cause mortality was examined. Using smokers without symptoms, CT imaging abnormalities or airflow obstruction as the reference population, individuals were classified as Possible COPD, Probable COPD and Definite COPD. Current Global initiative for obstructive Lung Disease (GOLD) criteria would diagnose 4062 (46%) of the 8784 study participants with COPD. The proposed COPDGene® 2019 diagnostic criteria would add an additional 3144 participants. Under the new criteria, 82% of the 8784 study participants would be diagnosed with Possible, Probable or Definite COPD. These COPD groups showed increased risk of disease progression and mortality. Mortality increased in patients as the number of their COPD characteristics increased, with a maximum hazard ratio for all cause-mortality of 5.18 (95% confidence interval [CI]: 4.15-6.48) in those with all 4 disease characteristics. A substantial portion of smokers with respiratory symptoms and imaging abnormalities do not manifest spirometric obstruction as defined by population normals. These individuals are at significant risk of death and spirometric disease progression. We propose to redefine the diagnosis of COPD through an integrated approach using environmental exposure, clinical symptoms, CT imaging and spirometric criteria. These expanded criteria offer the potential to stimulate both current and future interventions that could slow or halt disease progression in patients before disability or irreversible lung structural changes develop.

Physiologic Insights from the COPD Genetic Epidemiology Study

COPD Genetic Epidemiology Study (COPDGene®) manuscripts have provided important insights into chronic obstructive pulmonary disease (COPD) pathophysiology and outcomes, including a better understanding of COPD phenotypes relating computed tomography (CT) anatomic data to spirometric and patient-reported outcomes. Spirometry significantly underdiagnoses smoking-induced lung disease, and there is a marked improvement in sensitivity and specificity with CT scanning. This review also highlights the COPDGene® exploration of specific spirometry phenotypes (e.g.,PRISm), contributors to spirometric decline, composite physiologic measures, asthma-COPD overlap (ACO) syndrome, consequences of bronchodilator responsiveness, newer methods to assess small airway dysfunction, and spirometric correlates of comorbid diseases such as obesity and diabetes.

Subtypes of COPD Have Unique Distributions and Differential Risk of Mortality.

Previous attempts to explore the heterogeneity of chronic obstructive pulmonary disease (COPD) clustered individual patients using clinical, demographic, and disease features. We developed continuous multidimensional disease axes based on radiographic and spirometric variables that split into an airway-predominant axis and an emphysema-predominant axis. The COPD Genetic Epidemiology study (COPDGene®) is a cohort of current and former smokers, > 45 years, with at least 10 pack years of smoking history. Spirometry measures, blood pressure and body mass were directly measured. Mortality was assessed through continuing longitudinal follow-up and cause of death was adjudicated. Among 8157 COPDGene® participants with complete spirometry and computed tomography (CT) measures, the top 2 deciles of the airway-predominant and emphysema-predominant axes previously identified were used to categorize individuals into 3 groups having the highest risk for mortality using Cox proportional hazard ratios. These groups were also assessed for causal mortality. Biomarkers of COPD (fibrinogen, soluble receptor for advanced glycation end products [sRAGE], C-reactive protein [CRP], clara cell secretory protein [CC16], surfactant-D [SP-D]) were compared by group. High-risk subtype classification was defined for 2638 COPDGene® participants who were in the highest 2 deciles of either the airway-predominant and/or emphysema-predominant axis (32% of the cohort). These high-risk participants fell into 3 groups: airway-predominant disease only (APD-only), emphysema-predominant disease only (EPD-only) and combined APD-EPD. There was 26% mortality for the APD-only group, 21% mortality for the EPD-only group, and 54% mortality for the combined APD-EPD group. The APD-only group (n=1007) was younger, had a lower forced expiratory volume in 1 second (FEV1) percent (%) predicted and a strong association with the preserved ratio-impaired spirometry (PRISm) quadrant. The EPD-only group (n=1006) showed a relatively higher FEV1 % predicted and included largely GOLD stage 0, 1 and 2 partipants. Individuals in each of the 3 high-risk groups were at greater risk for respiratory mortality, while those in the APD-only group were additionally at greater risk for cardiovascular mortality. Biomarker analysis demonstrated a significant association of the APD-only group with CRP, and sRAGE demonstrated greatest significance with both the EPD-only and the combined APD-EPD groups. Among current and former smokers, individuals in the highest 2 deciles for mortality risk on the airway-predominant axis and the emphysema-predominant axis have unique associations to spirometric patterns, different imaging characteristics, biomarkers and causal mortality.

Identifying Smoking-Related Disease on Lung Cancer Screening CT Scans: Increasing the Value

Lung cancer screening (LCS) via chest computed tomography (CT) scans can save lives by identifying early-stage tumors. However, most smokers die of comorbid smoking-related diseases. LCS scans contain information about smoking-related conditions that is not currently systematically assessed. Identifying these common comorbid diseases on CT could increase the value of screening with minimal impact on LCS programs. We determined the prevalence of 3 comorbid diseases from LCS eligible scans and quantified related adverse outcomes. We studied COPD Genetic Epidemiology study (COPDGene®) participants (n=4078) who met criteria for LCS screening at enrollment (age > 55 years, and < 80 years, > 30 pack years smoking, current smoker or former smoker within 15 years of smoking cessation). CT scans were assessed for coronary artery calcification (CAC), emphysema, and vertebral bone density. We tracked the following clinically significant events: myocardial infarctions (MIs), strokes, pneumonia, respiratory exacerbations, and hip and vertebral fractures. Overall, 77% of eligible CT scans had one or more of these diagnoses identified. CAC (> 100 mg) was identified in 51% of scans, emphysema in 44%, and osteoporosis in 54%. Adverse events related to the underlying smoking-related diseases were common, with 50% of participants reporting at least one. New diagnoses of cardiovascular disease, emphysema and osteoporosis were made in 25%, 7% and 46%, of participants respectively. New diagnosis of disease was associated with significantly more adverse events than in participants who did not have CT diagnoses for both osteoporosis and cardiovascular risk. Expanded analysis of LCS CT scans identified individuals with evidence of previously undiagnosed cardiovascular disease, emphysema or osteoporosis that corresponded with adverse events. LCS CT scans can potentially facilitate diagnoses of these smoking-related diseases and provide an opportunity for treatment or prevention.

Pulmonary Subtypes Exhibit Differential Global Initiative for Chronic Obstructive Lung Disease Spirometry Stage Progression: The COPDGene® Study.

We classified individuals into pulmonary disease subtypes based on 2 underlying pathophysiologic disease axes (airway-predominant and emphysema-predominant) and their increased mortality risk. Our next objective was to determine whether some subcomponents of these subtypes are additionally associated with unique patterns of Global initiative for chronic Obstructive Lung Disease (GOLD) spirometry stage progression. After accounting for intra-individual measurement variability in spirometry measures between baseline (Phase 1) and the 5-year follow up (Phase 2) of the COPD Genetic Epidemiology (COPDGene®) study, 4615 individuals had complete data that would characterize patterns of disease progression over 5 years (2033 non-Hispanic whites; 827 African Americans; 48% female). Individuals could express increased risk for mortality on one or both of the primary subtype axes (airway-predominant or emphysema-predominant) and thus they were further classified into 6 groups: high-risk airway-predominant disease only (APD-only), moderate-risk airway-predominant disease only (MR-APD-only), high-risk emphysema-predominant disease only (EPD-only), combined high-risk airway- and emphysema-predominant disease (combined APD-EPD), combined moderate-risk airway- and emphysema-predominant disease (combined MR-APD-EPD), and no high-risk pulmonary subtype. Outcomes were dichotomized for GOLD spirometry stage progression from Phase 1 to Phase 2. Logistic regression of the progression outcomes on the pulmonary subtypes were adjusted for age, sex, race, and change in smoking status. The MR-APD-only group was associated with conversion from GOLD 0 to preserved ratio-impaired spirometry (PRISm) status (odds ratio [OR] 11.3, 95% confidence interval [CI] 5.7-22.1) and GOLD 0 to GOLD 2-4 (OR 6.0, 95% CI 2.0-18.0). The EPD-only group was associated with conversion from GOLD 0 to GOLD 1 (OR 2.4, 95% CI 1.2-4.6), and GOLD 1 to GOLD 2-4 (OR 2.6, 95% CI 1.0-6.9). Conversion between PRISm and GOLD 2-4 (31%-38%) occurred in both the APD-only and the MR-APD-only groups. Differential conversion occurs from GOLD 0 to PRISm and GOLD 0 to GOLD 1 based on groups expressing airway-predominant disease or emphysema-predominant disease independently or in combination. Airway-predominant and emphysema-predominant subtypes are highly important in determining patterns of early disease progression.

Race and Gender Disparities are Evident in COPD Underdiagnoses Across all Severities of Measured Airflow Obstruction.

The COPD Genetic Epidemiology (COPDGene®) study provides a rich cross-sectional dataset of patients with substantial tobacco smoke exposure, varied by race, gender, chronic obstructive pulmonary disease (COPD) diagnosis, and disease. We aimed to determine the influence of race, gender and Global initiative for chronic Obstructive Lung Disease (GOLD) stage on prevalence of prior COPD diagnosis at COPDGene® enrollment. Data from the complete phase 1 cohort of 10,192 participants were analyzed. Participants were non-Hispanic white and African-American, ≥45 years of age with a minimum of 10 pack years of cigarette smoking. Characterization upon enrollment included spirometry, demographics and history of COPD diagnosis determined by questionnaire. We evaluated the effects of race and gender on the likelihood of prior diagnosis of COPD and the interaction of race and GOLD stage, and gender and GOLD stage, as determined at study enrollment, on likelihood of prior diagnosis of COPD. We evaluated the 3-way interaction of race, gender and GOLD stage on prior diagnosis. African-Americans had higher odds of not having a prior COPD diagnosis at all GOLD stages of airflow obstruction versus non-Hispanic whites (p<0.0001). Women had higher odds of having a prior COPD diagnosis at all GOLD stages versus men (p<0.0001). Three-way interaction of race, gender and GOLD stage was not significant. African-Americans were less likely to have prior COPD regardless of the severity of airflow obstruction determined at study enrollment. Women were more likely to have a prior COPD diagnosis regardless of the severity of measured airflow obstruction. Race and gender are associated with significant disparities in COPD diagnosis.