Table 1.
Study population characteristics; demographics, smoking habits, respiratory symptoms and biomarker levels, comparing non-COPD and COPD and also presented by GOLD stages
| Non-COPD | COPD | P-value | GOLD 1 | GOLD 2 | GOLD 3-4 | |
|---|---|---|---|---|---|---|
| (n = 948) | (n = 594) | (n = 378) | (n = 190) | (n = 26) | ||
| Female, n (%) | 447 (47) | 248 (42) | 0.038 | 155 (41) | 87 (46) | 6 (23) |
| Age (years), median (IQR) | 67 (55–71) | 69 (57–71) | 0.015 | 69 (56–71) | 69 (58–71) | 70 (64–79) |
| BMI (kg/m2), median (IQR) | 26.8 (24.3-29.7) | 26.1 (23.5-28.7) | <0.001 | 25.8 (23.6-28.4) | 26.5 (23.5-29.0) | 27.6 (21.7-29.4) |
| Pack years, median (IQR) | 0.8 (0–12) | 14 (0–27) | <0.001 | 8.6 (0–24) | 18.5 (2.0-32.3) | 26.9 (14.8-42.5) |
| Non-smoker, n (%) | 443 (47) | 149 (25) | <0.001 | 113 (30) | 34 (18) | 2 (8) |
| Ex smoker, n (%) | 384 (41) | 247 (42) | 0.676 | 153 (40) | 75 (41) | 19 (73) |
| Current smoker, n (%) | 120 (13) | 197 (33) | <0.001 | 111 (29) | 81 (43) | 5 (19) |
| Productive cough, n (%) | 212 (22) | 238 (40) | <0.001 | 125 (33) | 93 (49) | 20 (77) |
| mMRC dyspnoea score ≥2, n (%) | 46 (5) | 75 (13) | <0.001 | 17 (5) | 40 (22) | 18 (69) |
| FEV1% predicted†, median (IQR) | 1.03 (0.93-1.13) | 0.85 (0.73-0.96) | <0.001 | 0.93 (0.86-1.01) | 0.70 (0.64-0.75) | 0.44 (0.37-0.47) |
| MMP-9 (ng/ml), median (IQR) | 505 (364–606) | 535 (315–653) | 0.017 | 513 (241–626) | 559 (379–662) | 647 (565–692) |
| TIMP-1 (ng/ml), median (IQR) | 316 (229–490) | 304 (227–439) | 0.252 | 311 (237–467) | 294 (218–425) | 298 (247–383) |
| Ratio of MMP-9/TIMP-1, median (IQR) | 1.36 (0.85-2.09) | 1.5 (0.83-2.32) | 0.168 | 1.46 (0.78-2.18) | 1.48 (0.9-2.5) | 1.95 (1.47-2.79) |
IQR = Inter quartile range. Significant p-values, p < 0.050, in bold.