From: Heterogeneous burden of lung disease in smokers with borderline airflow obstruction
Clinical Outcome | Group 1 Ever-smokers, Normal FEV1,\( \frac{\mathrm{FEV}1}{\mathrm{FVC}} \) < 0.7 and > LLN (Discordant Group) (n = 161) | Group 2 Ever-smokers, Normal FEV1, \( \frac{\mathrm{FEV}1}{\mathrm{FVC}} \)> 0.7 (n = 940) | Group 3 Never-smokers, Normal FEV1, \( \frac{\mathrm{FEV}1}{\mathrm{FVC}} \)> 0.7 (n = 190) | Overall p-value* Unadjusted (Adjusted) | P-values for pairwise comparisons (Unadjusted) | ||
---|---|---|---|---|---|---|---|
Group 1 vs. 2 | Group 1 vs. 3 | Group 2 vs. 3 | |||||
FEV1% predicted | 92.1 ± 12.0 | 97.5 ± 12.8 | 102.0 ± 11.5 | < 0.001 (< 0.001) | < 0.001 | < 0.001 | < 0.001** |
FEF25–75% % predicted | 61.2 ± 11.0 | 102.3 ± 33.4 | 121.3 ± 32.5 | < 0.001 (< 0.001) | < 0.001 | < 0.001 | < 0.001** |
6MWD (m) | 437.5 ± 109.6 | 437.2 ± 97.7 | 479.3 ± 103.4 | < 0.001 (0.49) | 0.97 | < 0.001 | < 0.001** |
St George’s Respiratory Questionnaire Total Score | 22.5 ± 17.4 | 24.2 ± 19.1 | 8.8 ± 10.0 | < 0.001 (< 0.001) | 0.28 | < 0.001 | < 0.001** |
COPD Assessment Test (CAT) | 10.7 ± 7.4 | 11.3 ± 8.1 | 4.7 ± 6.0 | < 0.001 (< 0.001) | 0.36 | < 0.001 | < 0.001** |
Use of either inhaled corticosteroid or bronchodilator | 34.4% | 25.1% | 3.9% | < 0.001 (< 0.001) | 0.01 | < 0.001 | < 0.001† |
Chronic bronchitis | 17.3% | 17.8% | 2.1% | < 0.001 (< 0.001) | 0.88 | < 0.001 | < 0.001† |
mMRC Dyspnea score ≥ 2 | 13.8% | 13.6% | 2.7% | < 0.001 (0.007) | 0.95 | < 0.001 | < 0.001† |
Change in FEV1 (ml/year) | − 60.5 ± 120.5 | −55.2 ± 127.5 | −41.2 ± 99.7 | 0.32 (0.94) | 0.64 | 0.17 | 0.19** |
Exacerbation (#/year) | 0.1 ± 0.4 | 0.1 ± 0.6 | 0.02 ± 0.1 | 0.02 (0.21) | 0.50 | 0.13 | 0.006** |