Table 3. Clinical factors associated with pulmonary artery dilation^†.

Clinical factors	Mean PA/Ao (95% CI)	β-coefficient (95% CI)‡	P value§
Oxygen use			<0.001
No (n=282)	0.78 (0.77, 0.79)	Reference
Yes (n=28)	0.87 (0.83, 0.91)	0.086 (0.045, 0.127)
Severity of bronchiectasis¶	0.79 (0.78, 0.80)	0.003 (−0.000, 0.006)	0.07
Tobacco use			0.12
Non-user (n=175)	0.78 (0.76, 0.79)	Reference
Former user (n=125)	0.80 (0.78, 0.82)	0.025 (−0.000, 0.050)
Current user (n=12)	0.81 (0.75, 0.87)	0.034 (−0.030, 0.097)
Sputum culture			0.55
Neither NTM nor pseudomonas (n=24)	0.79 (0.74, 0.83)	Reference
NTM (n=106)	0.79 (0.77, 0.81)	0.002 (−0.046, 0.051)
Pseudomonas (n=23)	0.82 (0.77, 0.86)	0.030 (−0.033, 0.093)
NTM and pseudomonas (n=31)	0.81 (0.77, 0.85)	0.025 (−0.033, 0.084)

^†, means and β-coefficients were estimated from a series of simple linear regression models in which each clinical factor was the single explanatory variable; ^‡, β-coefficients for categorical variables can be interpreted as “the difference between category k and the reference category”. For continuous variables, the β-coefficient can be interpreted as “for every unit increase in X, PA/Ao increases by β”; ^§, P values for categorical variables with 3 or more categories are type III P values for the overall association of that variable and PA/Ao; ^¶, severity of bronchiectasis was measured using the modified Reiff score. PA, pulmonary artery; Ao, aorta; CI, confidence interval; NTM, nontuberculous mycobacteria.