Subject characteristics
| Groningen | Laval | UBC | All centres | |||||
|---|---|---|---|---|---|---|---|---|
| COPD | No COPD | COPD | No COPD | COPD | No COPD | COPD | No COPD | |
| Number | 101 | 45 | 147 | 135 | 63 | 90 | 311 | 270 |
| Age, years | 58.0 (52.0–65.0) | 60.0 (54.0–66.0) | 66.0 (59.0–71.0)* | 62.0 (53.5–68.0) | 65.0 (58.0–71.0)* | 62.0 (56.0–70.75) | 64.0 (56.0–71.0) | 61.5 (54.0–68.8)† |
| Male/female, N | 56/45 | 20/25 | 83/64 | 76/59 | 43/20 | 49/41 | 182/129 | 145/125 |
| Smoking | ||||||||
| % Current/% ex | 19/81 | 44/56 | 26/74 | 16/84‡ | 51/49* | 34/66 | 29/71 | 27/73 |
| Pack-years, N | 33.0 (22.1–44.5) | 35.0 (21.0–41.0) | 50.0 (40.0–60.0)* | 38.4 (25.0–46.0) | 47.5 (34.9–74.0)* | 37.8 (25.0–48.9) | 42.0 (30.0–58.0) | 37.5 (25.0–48.0)† |
| GOLD stage, N | ||||||||
| I | 0 | 0 | 1 | 1 | ||||
| II | 30 | 134 | 52 | 216 | ||||
| III | 11 | 12 | 4 | 27 | ||||
| IV | 49 | 1 | 6 | 56 | ||||
| Not classified | 11 | 0 | 0 | 11 | ||||
| FEV1, %predicted | 26.5 (18.4–57.8) | 96.0 (89.2–104.8) | 67.4 (59.1–73.7)* | 94.3 (87.7–102.9) | 67.4 (58.2–74.3)* | 99.5 (89.5–108.7) | 64.3 (46.6–72.4) | 95.5 (88.8–106.2)† |
| FEV1/FVC, % | 42.6 (27.6–57.4) | 75.8 (72.9–80.0) | 59.2 (52.8–64.7)* | 75.3 (73.2–78.2) | 58.1 (51.3–63.4)* | 76.6 (73.3–79.5) | 56.3 (45.9–63.5) | 75.6 (73.2–79.1)† |
| TLCO, %predicted | – | – | 79.0 (63.5–91.0) | 92.0 (76.3–108.0) | 67.8 (51.0–76.6) | 85.2 (75.1–94.4) | 73.0 (59.7–87.8) | 89.0 (76.0–101.7)† |
Data are presented as medians with IQRs unless stated otherwise. Mann–Whitney U test was used to test differences between the groups.
*p<0.05 for difference with patients with COPD from Groningen.
†p<0.05 for difference between COPD (n=311) and non-COPD controls (n=270).
‡p<0.05 for difference with non-COPD controls from Groningen.
COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative on Obstructive Lung Disease; TLCO, transfer factor of the lung for carbon monoxide.