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BackgroundWe hypothesized that heterogeneity exists within the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 spirometric category and that different subgroups could be identified within this GOLD category.MethodsPre-randomization study participants from two clinical trials were symptomatic/asymptomatic GOLD 1 chronic obstructive pulmonary disease (COPD) patients and healthy controls. A hierarchical cluster analysis used pre-randomization demographics, symptom scores, lung function, peak exercise response and daily physical activity levels to derive population subgroups.ResultsConsiderable heterogeneity existed for clinical variables among patients with GOLD 1 COPD. All parameters, except forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC), had considerable overlap between GOLD 1 COPD and controls. Three-clusters were identified: cluster I (18 [15%] COPD patients; 105 [85%] controls); cluster II (45 [80%] COPD patients; 11 [20%] controls); and cluster III (22 [92%] COPD patients; 2 [8%] controls). Apart from reduced diffusion capacity and lower baseline dyspnea index versus controls, cluster I COPD patients had otherwise preserved lung volumes, exercise capacity and physical activity levels. Cluster II COPD patients had a higher smoking history and greater hyperinflation versus cluster I COPD patients. Cluster III COPD patients had reduced physical activity versus controls and clusters I and II COPD patients, and lower FEV1/FVC versus clusters I and II COPD patients.ConclusionsThe results emphasize heterogeneity within GOLD 1 COPD, supporting an individualized therapeutic approach to patients.Trial registrationwww.clinicaltrials.gov. NCT01360788 and NCT01072396.

BackgroundTo have a better understanding of the mechanisms of exercise limitation in mild-to-moderate chronic obstructive pulmonary disease (COPD), we compared detailed respiratory physiology in patients with COPD and healthy age- and sex-matched controls.MethodsData were collected during the pre-treatment, patient characterization phase of a multicenter, randomized, double-blind, crossover study. Patients with COPD met Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 or 2 spirometric criteria, were symptomatic, and had evidence of gas trapping during exercise. All participants completed pulmonary function and symptom-limited incremental treadmill exercise tests.ResultsChronic activity-related dyspnea measured by Baseline Dyspnea Index was similarly increased in patients with GOLD 1 (n = 41) and 2 (n = 63) COPD compared with controls (n = 104). Plethysmographic lung volumes were increased and lung diffusing capacity was decreased in both GOLD groups. Peak oxygen uptake and work rate were reduced in both GOLD groups compared with controls (p

BackgroundTo have a better understanding of the mechanisms of exercise limitation in mild-to-moderate chronic obstructive pulmonary disease (COPD), we compared detailed respiratory physiology in patients with COPD and healthy age- and sex-matched controls.MethodsData were collected during the pre-treatment, patient characterization phase of a multicenter, randomized, double-blind, crossover study. Patients with COPD met Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 or 2 spirometric criteria, were symptomatic, and had evidence of gas trapping during exercise. All participants completed pulmonary function and symptom-limited incremental treadmill exercise tests.ResultsChronic activity-related dyspnea measured by Baseline Dyspnea Index was similarly increased in patients with GOLD 1 (n = 41) and 2 (n = 63) COPD compared with controls (n = 104). Plethysmographic lung volumes were increased and lung diffusing capacity was decreased in both GOLD groups. Peak oxygen uptake and work rate were reduced in both GOLD groups compared with controls (p

Background: Thoracic computed tomography (CT) scans are widely performed in clinical practice, often leading to detection of airway or parenchymal abnormalities in asymptomatic or minimally symptomatic individuals. However, clinical relevance of CT abnormalities is uncertain in the general population. Methods: We evaluated data from 1361 participants aged ≥40 years from a Canadian prospective cohort comprising 408 healthy never-smokers, 502 healthy ever-smokers, and 451 individuals with spirometric evidence of chronic obstructive pulmonary disease (COPD) who had thoracic CT scans. CT images of subjects were visually scored for respiratory bronchiolitis(RB), emphysema(E), bronchial-wall thickening(BWT), expiratory air-trapping(AT), and bronchiectasis(B). Multivariable logistic regression models were used to assess associations of CT features with respiratory symptoms, dyspnea, health status as determined by COPD assessment test, and risk of clinically significant exacerbations during 12 months follow-up. Results: About 11% of life-time never-smokers demonstrated emphysema on CT scans. Prevalence increased to 30% among smokers with normal lung function and 36%, 50%, and 57% among individuals with mild, moderate or severe/very severe COPD, respectively. Presence of emphysema on CT was associated with chronic cough (OR,2.11; 95%CI,1.4–3.18); chronic phlegm production (OR,1.87; 95% CI,1.27–2.76); wheeze (OR,1.61; 95% CI,1.05–2.48); dyspnoea (OR,2.90; 95% CI,1.41–5.98); CAT score≥10(OR,2.17; 95%CI,1.42–3.30) and risk of ≥2 exacerbations over 12 months (OR,2.17; 95% CI, 1.42–3.0). Conclusions: Burden of thoracic CT abnormalities is high among Canadians ≥40 years of age, including never-smokers and smokers with normal lung function. Detection of emphysema on CT scans is associated with pulmonary symptoms and increased risk of exacerbations, independent of smoking or lung function. [ABSTRACT FROM AUTHOR]