Table 4.
Category | ||||||
---|---|---|---|---|---|---|
Non-obstructed (n = 2,406) |
Discordant (n = 389) |
Obstructed (n = 529) |
p-value* | |||
(LLN-Fixed-) | (LLN-Fixed+) | (LLN+Fixed+) |
Overall difference between categories |
LLN-Fixed+ versus LLN-Fixed- |
LLN-Fixed+ versus LLN+Fixed+ |
|
ΔFEV1 postbronchodilator, ml/year (SE) | ||||||
Smokers | -21 (3) | -21 (7) | -50 (5) | < 0.001 | 0.973 | 0.004 |
n | 578 | 138 | 292 | |||
Non-smokers | -15 (1) | -17 (4) | -36 (4) | < 0.001 | 0.624 | 0.004 |
n | 1828 | 251 | 237 | |||
ΔFEV1 prebronchodilator, ml/year (SE) | ||||||
Smokers | -13 (3) | -13 (7) | -50 (5) | < 0.001 | 0.998 | < 0.001 |
n | 578 | 138 | 292 | |||
Non-smokers | -9 (2) | -14 (5) | -30 (5) | < 0.001 | 0.301 | 0.016 |
n | 1828 | 251 | 237 | |||
ΔFVC postbronchodilator, ml/year (SE) | ||||||
Smokers | -18 (5) | -17 (9) | -33 (6) | 0.133 | 0.914 | 0.154 |
n | 578 | 138 | 292 | |||
Non-smokers | -15 (2) | -18 (6) | -22 (5) | 0.420 | 0.555 | 0.647 |
n | 1828 | 251 | 237 | |||
ΔFVC prebronchodilator, ml/year (SE) | ||||||
Smokers | -12 (5) | -5 (10) | -46 (7) | < 0.001 | 0.544 | 0.001 |
n | 578 | 138 | 292 | |||
Non-smokers | -7 (2) | -15 (6) | -16 (6) | 0.226 | 0.230 | 0.929 |
n | 1828 | 251 | 237 |
LNN: lower limit of normal; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; Δ: change;
* between group differences were analyzed with a random coefficient regression model with random intercept and random slope and were adjusted for differences in inhaled corticosteroid use between the categories. Inhaled corticosteroid use was statistically significantly associated with lung function decline at p < 0.001 level in all regression models
Fixed: FEV1/FVC < 0.70; LLN based on Swanney prediction equations [6]