TABLE 5.

Multivariable analysis for the differences in the ratio of blood vessel volume in vessels <5 mm² in cross-section (BV5) to total blood vessel volume (TBV) between subjects with lower lobes bronchiectasis and without bronchiectasis using alternate definitions of the disease

Alternate definition	Difference in lower-lobe BV5/TBV	se	p-value
1) Two or more bronchial paths involved
Entire cohort	−1.8	0.40	<0.0001
Emphysema status subcohort
Subjects with emphysema	−1.8	0.57	0.002
Subjects without emphysema	−1.3	0.49	0.009
2) Lack of airway lumen tapering+airway seen within 1 cm of the pleura
Entire cohort	−2.1	0.58	0.0003
Emphysema status subcohort
Subjects with emphysema	−1.9	0.77	0.01
Subjects without emphysema	−2.4	0.80	0.003

The differences in lower-lobe BV5/TBV×100 are from a multivariable regression model where the presence of bronchiectasis in the lower lobes is the main predictor. Analyses were adjusted for age, sex, race, pack-years smoked, forced expiratory volume in 1 s % predicted, total lung capacity determined by computed tomography % predicted, resting arterial oxygen saturation, percentage of low-attenuation areas below −950 Hounsfield units (%LAA₋₉₅₀) of the lower lobes and coronary artery disease. For the analysis stratified by emphysema of the lower lobes, %LAA₋₉₅₀ was omitted as a covariate.