Table 4.

Association between Vascular Pruning and Prospective Asthma Exacerbations

	Odds Ratio for Reporting Asthma Exacerbation during Follow-up	Confidence Interval	P Value
BV5/TBV (low vs. high)	1.51	0.65 to 3.54	0.341
BV10/TBV (low vs. high)	2.50	1.05 to 5.98	0.039

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; TBV = total pulmonary blood vessel volume.

BV5/TBV and BV10/TBV dichotomized at 25th percentile. That is, effect estimates are expressed as odds of those with the most pruning (top 25%) vs. those with less pruning (bottom 75%).

All models were adjusted for baseline values of age, sex, race, body mass index, prebronchodilator FEV₁ percent predicted, and asthma control test score as well as for a reported history of exacerbation in the year before the baseline visit.

n with longitudinal data available = 214. n who reported exacerbation during follow-up = 87 (40.7%).