Table 1. Characteristics of study patients at baseline computed tomography scan (n = 53).
| Former (n = 31) | Current (n = 22) | p value | |||
| Age (years) | 70 | (60.0, 75.0) | 65.5 | (62.0, 72.3) | 0.54 |
| Sex (male:female) | 28∶3 | 20∶2 | 0.94 | ||
| Body mass index | 22.7 | (21.3, 24.2) | 21.3 | (19.6, 22.9) | 0.06 |
| Smoking history (pack-years) | 50.0 | (40.0, 94.0) | 59.0 | (45.5, 99.0) | 0.36 |
| Blood COHb (%)* | 1.0 | (0.7, 1.2) | 2.6 | (1.8, 3.8) | <0.0001 |
| FEV1 (L) | 1.94 | (1.50, 2.59) | 1.96 | (1.25, 2.47) | 0.75 |
| %FEV1 (%) | 71.0 | (57.5, 88.0) | 71.2 | (53.8, 81.5) | 0.34 |
| GOLD stage (I/II/III/IV) | 10/19/2/0 | 8/10/5/0 | 0.21 | ||
| LAA% | 29.7 | (25.0, 31.5) | 25.8 | (22.7, 30.1) | 0.08 |
| LogLAA% | 1.47 | (1.40, 1.50) | 1.41 | (1.36, 1.48) | 0.08 |
| D | 1.80 | (1.55, 2.02) | 1.83 | (1.67, 2.32) | 0.25 |
| LAN | 137 | (84, 195) | 123 | (61, 197) | 0.30 |
| CT-TLV (L) | 5.02 | (4.25, 5.42) | 4.84 | (4.26, 6.08) | 0.57 |
| Tiotropium (%)† | 6.5 | 9.0 | 0.72 | ||
| Long-acting beta2-agonist (%)† | 9.7 | 4.5 | 0.47 | ||
| Inhaled corticosteroid (%)† | 19.4 | 9.0 | 0.09 | ||
| Salmeterol/fluticasone combination (%)† | 0 | 0 | 1.00 | ||
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.