Table 1.

Characteristics of the training and test sets of participants (n = 56).

Variables	Participants in training dataset (n = 42)	Participants in test dataset (n = 14)	P-value*
Age, years	73.5 ± 7.5	71.9 ± 7.0	0.43
Male, N (%)	25 (59.5%)	9 (64.3%)	0.75
Race/Ethnicity, N (%)			0.60
White	21 (50.0%)	8 (57.1%)
Black	12 (28.6%)	5 (35.7%)
Hispanic	9 (21.4%)	1 (7.1%)
Current smokers, N (%)	10 (23.8%)	6 (42.9%)	0.19
Pack years	38.2 ± 20.9	46.8 ± 28.9	0.47
COPD, N (%)	22 (52.4%)	8 (57.1%)	0.76
None	20 (47.6%)	6 (42.9%)
Mild	11 (26.2%)	3 (21.4%)
Moderate	11 (26.2%)	5 (35.7%)
% normal-ventilated	63.3 ± 21.3	59.7 ± 13.9	0.27
% hypo-ventilated	25.0 ± 14.8	26.8 ± 11.6	0.36
% non-ventilated	11.7 ± 10.1	13.5 ± 6.3	0.13

Note. — For quantitative vsariables, data are presented as mean ± standard deviation unless otherwise noted. COPD = chronic obstructive pulmonary disease.

^*The Mann-Whitney U, Chi-squared, and Fisher’s exact tests were used as appropriate to compare differences between the training and test subjects.