Table 2.
Characteristics of study population (immunohistochemical study)
| Never-smokers | Smokers without COPD | COPD GOLD II | COPD GOLD III–IV | |
|---|---|---|---|---|
| Number | 18 | 28 | 34 | 14 |
| Gender ratio (male/female) | 5/13# | 20/8# | 32/2# | 5/9# |
| Age (years) | 65 (61–71) | 66 (57–71) | 66 (59–69) | 58 (55–60)*,§,‡ |
| Current smoker/ex-smoker | – | 16/12 | 21/13 | 0/14 |
| Smoking history (PY) | 0 (0–0) | 34 (15–49)* | 45 (39–60)*,§ | 36 (30–42)*,‡ |
| FEV1 post-BD (L) | 2.4 (2.0–3.0) | 2.7 (2.3–3.3) | 2.1 (1.8–2.4)*,§ | 0.6 (0.5–0.9)*,§,‡ |
| FEV1 post-BD (% predicted) | 107 (92–118) | 95 (93–113) | 69 (61–75)*,§ | 24 (20–34)*,§,‡ |
| FEV1/FVC post-BD (%) | 79 (74–83) | 77 (72–79) | 56 (50–61)*,§ | 31 (26–36)*,§,‡ |
| DLCO (% predicted) | 88 (80–104) | 83 (65–104) | 71 (53–87)* | 33 (28–36)*,§,‡ |
| KCO (% predicted) | 94 (86–122) | 96 (79–106) | 90 (67–108)* | 47 (42–57)*,§,‡ |
| ICS (yes/no) | 1/17# | 2/26# | 14/20# | 14/0# |
Notes: n=94. Data are presented as median (IQR). Mann–Whitney U-test:
*
p<0.05 versus never-smokers;
§
p<0.05 versus smokers without COPD;
‡
p<0.05 versus COPD GOLD II. Fisher’s exact test:
#
p<0.001. ‘–’ indicates not applicable.
Abbreviations: COPD, chronic obstructive pulmonary disease; DLCO, diffusing capacity of the lung for carbon monoxide; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; ICS, inhaled corticosteroids; IQR, interquartile range; KCO, the ratio of DLCO to alveolar volume; post-BD, post-bronchodilator; PY, pack years.