Table 1.
Cohort Characteristics
| n Available | ||
|---|---|---|
| Clinical characteristics | ||
| Age, yr, mean ± SD | 46.0 ± 14.8 | 237 |
| Female, n (%) | 157 (66.2) | 237 |
| Nonwhite, n (%) | 93 (39.2) | 237 |
| Body mass index, kg/m2, mean ± SD | 32.8 ± 9.0 | 237 |
| Spirometric characteristics | ||
| Percent predicted FEV1, mean ± SD | 73.2 ± 20.8 | 237 |
| Percent predicted FVC, mean ± SD | 84.9 ± 18.1 | 237 |
| Percent change in FEV1 with bronchodilator, mean ± SD | 17.4 ± 17.3 | 237 |
| Methacholine challenge PC20, mean ± SD | 2.9 ± 3.5 | 103 |
| Asthma category, n (%) | ||
| Healthy control | 11 (4.6) | 237 |
| Nonsevere | 68 (28.7) | 237 |
| Severe | 158 (66.7) | 237 |
| Asthma control | ||
| Asthma control test score, mean ± SD | 16.4 ± 5.0 | 226 |
| Poor asthma control, n (%) | 131 (58.0) | 226 |
| Eosinophilia | ||
| Peripheral eosinophil, %, mean ± SD | 4.1 ± 3.5 | 233 |
| Sputum eosinophil, %, mean ± SD | 4.2 ± 9.4 | 176 |
| Fractional exhaled nitric oxide, mean ± SD | 29.7 ± 27.4 | 234 |
| Steroid response | ||
| Change in peripheral eosinophil, %, mean ± SD | −1.9 ± 2.9 | 121 |
| Change in sputum eosinophil, %, mean ± SD | −2.6 ± 8.1 | 141 |
| Change in fractional exhaled nitric oxide, mean ± SD | −7.1 ± 20.6 | 218 |
| Change in FEV1, mean ± SD | 0.09 ± 0.27 | 223 |
| Other sputum characteristics | ||
| Sputum neutrophil, %, mean ± SD | 55.0 ± 24.7 | 176 |
| BAL | ||
| BAL neutrophil, %, mean ± SD | 2.0 ± 3.0 | 93 |
| BAL eosinophil, %, mean ± SD | 1.6 ± 5.4 | 93 |
| BAL serum amyloid A/lipoxin A4 ratio, mean ± SD | 109.1 ± 340.3 | 58 |
| Quantitative CT measures | ||
| CT measured lung volume, L, mean ± SD | 5.0 ± 1.2 | 237 |
| Percent low-attenuation area, mean ± SD | 2.0 ± 2.3 | 237 |
| Percent air trapping on expiratory CT, mean ± SD | 10.8 ± 2.8 | 187 |
| Measures of pulmonary vasculature | ||
| BV5, ml, mean ± SD | 111.0 ± 28.4 | 237 |
| BV10, ml, mean ± SD | 134.8 ± 31.6 | 237 |
| TBV, ml, mean ± SD | 188.7 ± 42.6 | 237 |
| BV5/TBV, mean ± SD | 0.587 ± 0.066 | 237 |
| BV10/TBV, mean ± SD | 0.714 ± 0.050 | 237 |
| Longitudinal exacerbation analyses | ||
| Duration of follow-up, yr, mean ± SD | 2.6 ± 1.2 | 214 |
| Number of exacerbations per yr, mean ± SD | 1.2 ± 1.6 | 214 |
| Participants who reported at least 1 exacerbation during follow-up, n (%) | 87 (40.7) | 214 |
Definition of abbreviations: BV5 = aggregate vessel volume for vessels less than 5 mm2 in cross-sectional area; BV10 = aggregate vessel volume for vessels less than 10 mm2 in cross-sectional area; CT = computed tomography; PC20 = provocative concentration causing a 20% fall in FEV1; TBV = total pulmonary blood vessel volume.
Low-attenuation area is defined as the percentage of lung occupied by tissue with attenuation less than −950 Hounsfield units on inspiratory CT obtained.
Percentage of area with air trapping is defined as the percentage of lung occupied by tissue with attenuation less than −856 Hounsfield units on expiratory CT.