Table 2.

Univariate Correlations

Parameter	BV5/TBV		BV10/TBV
	r	P Value	R	P Value
Prebronchodilator FEV1 pp	0.41	<0.001	0.44	<0.001
Prebronchodilator FVC pp	0.44	<0.001	0.45	<0.001
Percent change in FEV1 with bronchodilator	−0.12	0.057	−0.12	0.061
Methacholine challenge PC20	0.10	0.333	0.09	0.387
Asthma control test score	0.25	<0.001	0.22	0.001
Low-attenuation area	0.06	0.320	0.07	0.280
Percent air trapping on expiratory CT	−0.14	0.063	−0.16	0.033
Peripheral eosinophil, %	−0.15	0.022	−0.22	0.001
Sputum eosinophil, %	−0.16	0.033	−0.21	0.005
Fractional exhaled nitric oxide	−0.01	0.831	−0.05	0.449
Sputum neutrophil, %	−0.03	0.682	−0.06	0.413
BAL neutrophil, %	−0.07	0.520	−0.09	0.384
BAL eosinophil, %	0.14	0.180	0.14	0.186
BAL serum amyloid A/lipoxin A4 ratio	−0.57	<0.001	−0.59	<0.001
Steroid response
Change in prebronchodilator FEV1	0.00	0.975	−0.01	0.877
Change in peripheral eosinophil, %	0.20	0.028	0.30	0.001
Change in sputum eosinophil, %	0.05	0.552	0.12	0.163
Change in fractional exhaled nitric oxide	−0.07	0.315	−0.04	0.523

Definition of abbreviations: BV5 = blood vessel volume for vessels less than 5 mm² in cross-sectional area; BV10 = blood vessel volume for vessels less than 10 mm² in cross-sectional area; CT = computed tomography; PC₂₀ = provocative concentration causing a 20% fall in FEV₁; pp = percent predicted; TBV = total pulmonary blood vessel volume.

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), FEV₁ steroid response (n = 223), 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).