Table 1.
Mean ± SD, median (IQR), or proportion of the main anthropometric, clinical, functional and radiological variables in the three groups of participants
| COPD (n = 2164) |
Smoking controls (n = 337) |
Non-smoking controls (n = 245) |
p value | |
|---|---|---|---|---|
| Clinical data | ||||
| Age (years) | 63.4 ± 7.1a, b | 55.4 ± 9.0 | 54.1 ± 9.0 | < 0.001 |
| Pack-years | 48.6 ± 27.1 a, b | 31.6 ± 21.5b | 0.2 ± 1.1 | < 0.001 |
| Current Smokers (%) | 36a | 61 | < 0.001 | |
| BMI (kg/m2) | 26.5 ± 5.7b | 26.8 ± 4.6 | 27.7 ± 5.4 | 0.004 |
| FFMI (kg/m2) | 17.2 ± 2.8 | 17.1 ± 2.6 | 17.2 ± 2.7 | 0.842 |
| mMRC Score | 1.7 ± 1.1 a, b | 0.2 ± 0.5b | 0.1 ± 0.3 | < 0.001 |
| SGRQ-C total score | 50.1 ± 20.3 a, b | 9.6 ± 12.3b | 4.8 ± 6.5 | < 0.001 |
| Number of exacerbationsc | 0.9 ± 1.2 a, b | 0.0 ± 0.1 | 0.0 ± 0.1 | < 0.001 |
| Heart trouble (%) | 26 a, b | 11 | 9 | < 0.001 |
| Heart attack (%) | 9 a, b | 3 | 1 | < 0.001 |
| Stroke (%) | 4d | 2 | 1 | 0.018 |
| Heart failure (%) | 7 a, b | 1 | 0 | < 0.001 |
| Arrhythmia (%) | 12a, d | 5 | 7 | < 0.001 |
| Osteoporosis (%) | 14 a, b | 5 | 5 | < 0.001 |
| Diabetes (%) | 10b | 7 | 5 | 0.003 |
| Inflammatory bowel disease (%) | 5e | 2 | 4 | 0.127 |
| Peptic ulcer (%) | 11b | 7d | 3 | < 0.001 |
| Reflux/heartburn (%) | 27d | 29d | 19 | 0.031 |
| Depression requiring tx (%) | 17 | 15 | 14 | 0.506 |
| Physiology | ||||
| FEV1 (% predicted) | 48.3 ± 15.8 a, b | 108.6 ± 12.0d | 114.8 ± 13.9 | < 0.001 |
| FEV1/FVC (%) | 44.8 ± 11.6 a, b | 79.2 ± 5.2d | 81.1 ± 5.2 | < 0.001 |
| FEV1 reversibility (%) | 10.7 ± 13.7 a, b | 4.5 ± 5.8d | 2.7 ± 4.5 | < 0.001 |
| Distance walked (metres) | 369 ± 122 | |||
| BODE index | 3.2 ± 2.1 | |||
| Imaging | ||||
| Emphysema (%) | 17.6 ± 12.2 a, b | 2.4 ± 3.1b | 4.1 ± 4.2 | < 0.001 |
ap < 0.01 vs. smoking controls; b< 0.01 vs. non-smoking controls; c In the year prior to study dp < 0.05 vs. non-smoking controls. entry. ep < 0.05 vs. smoking controls. Abbreviations: tx: treatment.