Table 1.
Clinical parameters included in the analysis.
Fig 1.
Frequency distributions for pulmonary function, peak V′o2, BDI score and physical activity.
a) forced expiratory volume in 1 second (FEV1); b) FEV1/forced vital capacity (FVC) ratio; c) total lung capacity (TLC); d) functional residual capacity (FRC); e) residual volume (RV); f) diffusion capacity (Dlco); g) peak oxygen uptake (V′o2 peak); h) baseline dyspnea index (BDI) score; i) number of steps per day; j) and daily time spent in physical activity >3 metabolic equivalents (METs). GOLD: Global Initiative for Chronic Obstructive Lung Disease.
Fig 2.
Determination of the number of clusters.
a) Using three statistics (the statistical value of pseudo F statistic and cubic clustering criterion are reported on the left Y axis while the statistical value for pseudo t2 statistic is reported on the right Y axis) and b) hierarchical Ward’s clustering method.
Fig 3.
Proportion of controls subjects and patients with GOLD grade 1 COPD within each cluster.
Table 2.
Characteristics of patients with GOLD grade 1 COPD by cluster.
Fig 4.
Pulmonary function parameters expressed as percentage of predicted values by cluster.
a) forced expiratory volume in 1 second (FEV1); b) total lung capacity (TLC); c) functional residual volume (FRC); d) residual volume (RV); and e) diffusion capacity (Dlco); as well as f) FEV1/forced vital capacity (FVC) ratio by cluster of patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade 1 chronic obstructive pulmonary disease. Values are mean ± SD. Dashed lines represent mean values in control subjects. *p<0.01 versus healthy controls; †p<0.05 versus cluster I; ‡p<0.01 versus cluster I and II.
Fig 5.
V′o2 peak relative to body weight and daily physical activity levels by cluster.
a) Peak oxygen consumption (V′o2 peak) relative to body weight; b) mean steps per day; c) mean daily energy expenditure (EE); d) mean daily time >3 metabolic equivalents (METs); and e) baseline dyspnea index (BDI) score by cluster of patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade 1 chronic obstructive pulmonary disease. Values are mean ± SD. Dashed lines represent mean values in control subjects. *p<0.01 versus controls subjects; †p<0.05 versus cluster I and II.
Table 3.
Peak physiological response to exercise for patients with GOLD grade COPD by cluster.