Table 2.

Patient clinical characteristics in each COPD category

Notes: Values are mean ± SD. Other values are number (%). *P<0.05; **P<0.01.

Abbreviations: BMI, body mass index; COPD, chronic obstructive pulmonary disease; DL_CO/VA (%predicted), percentage of the diffusing capacity for carbon monoxide per liter of lung volume predicted value; FEV₁ (%predicted), percentage of the FEV₁ predicted value; FVC, forced vital capacity; LAV, low attenuation volume; RV, residual volume; SD, standard deviation; TLC, total lung capacity; RV/TLC, ratio of residual volume to total lung capacity; VC, vital capacity; FEV₁, forced expiratory volume in 1 second.