Characteristics of study patients at baseline computed tomography scan (n = 53).

Data are expressed as medians (25th and 75th percentiles). Abbreviations: COHb, carboxyhemoglobin; CT-TLV, total lung volume measured by computed tomography; Current, current smokers; D, index of low attenuation cluster analysis; FEV1, forced expiratory volume in one second; %FEV1, FEV1% predicted; Former, former smokers; GOLD, Global Initiative for Chronic Obstructive Lung Disease;LAA%, ratio (%) of low attenuation area; LAN; number of low attenuation clusters.*Blood COHb was not measured in one current smoker.†Ratio (%) of patients prescribed with these drugs.