Table 3.
Multivariable Associations
| Parameter | BV5/TBV |
BV10/TBV |
||||
|---|---|---|---|---|---|---|
| Change Per 1 SD | Confidence Interval | P Value | Change Per 1 SD | Confidence Interval | P Value | |
| Effect on clinical parameter expressed per 1 SD change in pruning | ||||||
| Prebronchodilator FEV1 pp | 7.10 | 3.28 to 10.92 | <0.001 | 7.28 | 3.55 to 10.73 | 0.001 |
| Prebronchodilator FVC pp | 4.71 | 1.59 to 7.84 | <0.001 | 4.77 | 1.83 to 7.71 | <0.001 |
| Percent change in FEV1 with bronchodilator | 2.05 | −1.01 to 5.10 | 0.370 | 2.18 | −0.72 to 5.08 | 0.237 |
| Methacholine challenge PC20 | −0.15 | −1.37 to 1.06 | 1.000 | −0.20 | −1.37 to 0.96 | 1.000 |
| Asthma control test score | 0.23 | −0.71 to 1.17 | 1.000 | 0.18 | −0.72 to 1.07 | 1.000 |
| Low-attenuation area | 0.12 | −0.34 to 0.58 | 1.000 | 0.23 | −0.21 to 0.67 | 0.732 |
| Percent air trapping on expiratory CT | −2.09 | −4.87 to 0.69 | 0.238 | −1.55 | −4.24 to 1.13 | 0.584 |
| Peripheral eosinophil, % | −1.12 | −1.91 to −0.32 | 0.001 | −1.27 | −2.02 to −0.52 | <0.001 |
| Sputum eosinophil, % | −3.05 | −5.73 to −0.38 | 0.015 | −3.28 | −5.82 to −0.74 | 0.004 |
| BAL eosinophil, % | 0.52 | −2.01 to 3.05 | 1.000 | 0.45 | −1.92 to 2.82 | 1.000 |
| Fractional exhaled nitric oxide | −3.73 | −10.39 to 2.92 | 0.985 | −4.60 | −10.92 to 1.72 | 0.367 |
| Sputum neutrophil, % | 0.03 | −6.97 to 7.03 | 1.000 | −0.49 | −7.19 to 6.21 | 1.000 |
| BAL neutrophil, % | 0.13 | −1.21 to 1.48 | 1.000 | −0.01 | −1.27 to 1.25 | 1.000 |
| BAL serum amyloid A/lipoxin A4 ratio | −269.7 | −441.3 to −98.1 | <0.001 | −268.6 | −418.9 to −118.2 | <0.001 |
| Steroid response | ||||||
| Change in prebronchodilator FEV1 | −0.01 | −0.08 to 0.06 | 1.000 | −0.01 | −0.07 to 0.06 | 1.000 |
| Change in peripheral eosinophil, % | 0.72 | −0.16 to 1.60 | 0.197 | 0.94 | 0.12 to 1.76 | 0.014 |
| Change in sputum eosinophil, % | 1.46 | −1.33 to 4.26 | 1.000 | 1.96 | −0.64 to 4.56 | 0.306 |
| Change in fractional exhaled nitric oxide | 1.04 | −4.01 to 6.09 | 1.000 | 1.77 | −3.04 to 6.58 | 1.000 |
| Effect on pruning measure expressed per 1 SD change in clinical parameter | ||||||
| Prebronchodilator FEV1 pp | 0.0170 | 0.0078 to 0.0261 | <0.001 | 0.0143 | 0.0071 to 0.0214 | 0.001 |
| Prebronchodilator FVC pp | 0.0173 | 0.0058 to 0.0288 | <0.001 | 0.0147 | 0.0056 to 0.0237 | <0.001 |
| Percent change in FEV1 with bronchodilator | 0.0069 | −0.0034 to 0.0172 | 0.370 | 0.0061 | −0.0020 to 0.0142 | 0.237 |
| Methacholine challenge PC20 | −0.0017 | −0.0148 to 0.0115 | 1.000 | −0.0018 | −0.0121 to 0.0085 | 1.000 |
| Asthma control test score | 0.0020 | −0.0063 to 0.0103 | 1.000 | 0.0013 | −0.0052 to 0.0078 | 1.000 |
| Low-attenuation area | 0.0023 | −0.0069 to 0.0116 | 1.000 | 0.0039 | −0.0034 to 0.0111 | 0.732 |
| Percent air trapping on expiratory CT | −0.0080 | −0.0186 to 0.0026 | 0.238 | −0.0048 | −0.0131 to 0.0035 | 0.584 |
| Peripheral eosinophil, % | −0.0138 | −0.0237 to −0.0039 | 0.001 | −0.0130 | −0.0206 to −0.0053 | <0.001 |
| Sputum eosinophil, % | −0.0119 | −0.0223 to −0.0015 | 0.015 | −0.0104 | −0.0185 to −0.0023 | 0.004 |
| BAL eosinophil, % | 0.0022 | −0.0086 to 0.0130 | 1.000 | 0.0016 | −0.0070 to 0.0102 | 1.000 |
| Fractional exhaled nitric oxide | −0.0051 | −0.0143 to 0.0040 | 0.985 | −0.0052 | −0.0123 to 0.0019 | 0.367 |
| Sputum neutrophil, % | 0.00004 | −0.0100 to 0.0100 | 1.000 | −0.0006 | −0.0084 to 0.0072 | 1.000 |
| BAL neutrophil, % | 0.0013 | −0.0117 to 0.0142 | 1.000 | −0.0001 | −0.0104 to 0.0103 | 1.000 |
| BAL serum amyloid A/lipoxin A4 ratio | −0.0233 | −0.0380 to −0.0085 | <0.001 | −0.0208 | −0.0325 to −0.0092 | <0.001 |
| Steroid response | ||||||
| Change in prebronchodilator FEV1 | −0.0012 | −0.0106 to 0.0083 | 1.000 | −0.0007 | −0.0081 to 0.0067 | 1.000 |
| Change in peripheral eosinophil, % | 0.0117 | −0.0026 to 0.0259 | 0.197 | 0.0126 | 0.0016 to 0.0236 | 0.014 |
| Change in sputum eosinophil, % | 0.0058 | −0.0052 to 0.0168 | 1.000 | 0.0065 | −0.0021 to 0.0152 | 0.306 |
| Change in fractional exhaled nitric oxide | 0.0020 | −0.0078 to 0.0119 | 1.000 | 0.0028 | −0.0049 to 0.0105 | 1.000 |
For definition of abbreviations, see Table 2.
For effect on clinical parameter expressed per 1 SD change in pruning, change is expressed as an absolute amount per 1 SD increase in BV5/TBV or BV10/TBV. For instance, for 1 SD increase in BV5/TBV the prebronchodilator FEV1 pp increases by 7.10.
For effect on pruning measure expressed per 1 SD change in clinical parameter, change is expressed as an absolute amount per 1 SD increase in clinical, laboratory, or imaging parameter. For instance, for 1 SD increase in the prebronchodilator FEV1 pp the BV5/TBV increases by 0.0170.
Models were adjusted for age, sex, race, body mass index, percentage of lung occupied by low-attenuation area, CT-measured lung volume, and prebronchodilator FEV1 pp except for the models for the baseline spirometric measures, which were not adjusted for prebronchodilator FEV1 pp, and the models for the densitometric CT measurements, which were not adjusted for low-attenuation area.
P values and confidence intervals given are corrected for multiple comparisons within each group/family as represented by boldface, using the Bonferroni correction. For example, for the spirometric analyses the P values given are adjusted for a total of four comparisons (BV5/TBV with FEV1 and FVC, and BV10/TBV with FEV1/FVC). Confidence intervals are similarly corrected. For example, for the spirometric analyses, the confidence intervals given are the 98.75% confidence intervals.
n = 237 for all analyses except for: methacholine challenge (n = 103), sputum eosinophil % (n = 176), BAL neutrophil % (n = 92), BAL eosinophil % (n = 92), BAL serum amyloid A/lipoxin A4 (n = 58), peripheral eosinophil steroid response (n = 121), sputum eosinophil steroid response (n = 141), fractional exhaled nitric oxide steroid response (n = 218), and air trapping (n = 187).