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-lobe bronchiectasis and without bronchiectasis

Cohort/subcohortDifference in lower-lobe BV5/TBVsep-value
Entire cohort−1.50.35<0.0001
Emphysema status subcohort
 Subjects with emphysema−1.80.520.0008
 Subjects without emphysema−1.60.460.0005

The differences in lower-lobe BV5/TBV×100 are from a multivariable regression model where the presence of lower lobes bronchiectasis 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.