Change in lung function, as measured every 3 months, patients with COPD and the comparator groups
Spirometric variable | Visit (months) | NSC | SC | Patients with COPD | p Values | ||
NSC vs SC | NCS vs patients with COPD | SC vs patients with COPD | |||||
Post-bronchodilator FEV1 change (litres) | 0 | 0.08 (0.14) | 0.14 (0.15) | 0.12 (0.15) | <0.001 | <0.001 | 0.110 |
3 | 0.09 (0.16) | 0.11 (0.22) | 0.12 (0.14) | 0.059 | <0.001 | 0.308 | |
6 | 0.08 (0.14) | 0.12 (0.13) | 0.13 (0.15) | 0.002 | <0.001 | 0.893 | |
12 | 0.07 (0.17) | 0.11 (0.14) | 0.12 (0.14) | 0.002 | <0.001 | 0.201 | |
Post-bronchodilator FVC change (litres) | 0 | –0.00 (0.20) | 0.01 (0.22) | 0.25 (0.34) | 0.656 | <0.001 | <0.001 |
3 | –0.01 (0.22) | 0.01 (0.31) | 0.25 (0.32) | 0.464 | <0.001 | <0.001 | |
6 | –0.01 (0.20) | 0.03 (0.19) | 0.24 (0.32) | 0.111 | <0.001 | <0.001 | |
12 | –0.02 (0.19) | 0.02 (0.17) | 0.23 (0.31) | 0.197 | <0.001 | <0.001 | |
Post-bronchodilator FEV1/FVC change (%) | 0 | 2.13 (3.46) | 2.98 (4.25) | 0.29 (4.35) | 0.025 | <0.001 | <0.001 |
3 | 2.29 (3.93) | 2.51 (3.41) | 0.35 (4.15) | 0.542 | <0.001 | <0.001 | |
6 | 2.42 (3.20) | 2.45 (3.29) | 0.61 (4.43) | 0.923 | <0.001 | <0.001 | |
12 | 1.93 (4.20) | 2.31 (3.59) | 0.71 (4.13) | 0.291 | <0.001 | <0.001 |
Data are given as mean (SD).
COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; NCS, non-smoker control; SC, smoker control.