Exhaled breath condensate pH as a biomarker of COPD severity in ex-smokers

Respiratory Research

Table 1 Demographic and functional characteristics of the study subjects

	Controls n = 112	COPD all n = 161	COPD ex-smokers n = 86	COPD current smokers n = 75
Age	65 ± 7	65 ± 10	68 ± 9	62 ± 10
Gender M/F (n)	88/24	122/39	62/24	60/15
Pack-years	61 ± 13	60 ± 14	64 ± 16	64 ± 22
Current/ex-smokers (n)	54/58	75/86
FEV ₁ (% pred.)	93.8 ± 10.4	53.5 ± 17.7*	48.6 ± 17.3	59.2 ± 16.4^#
FEV ₁ /FVC	83.5 ± 9.8	56.8 ± 10.5*	54.0 ± 10.7	59.9 ± 9.4^#
IC/TLC	0.72 ± 0.13	0.30 ± 0.09*	0.29 ± 0.09	0.30 ± 0.08
RV/TLC	0.35 ± 0.07	0.58 ± 0.11*	0.59 ± 0.12	0.56 ± 0.11
DL _CO (%pred.)	87.8 ± 8.5	59.4 ± 22.2*	54.9 ± 23.8	64.1 ± 19.5^†
GOLD COPD stage (I/II/III/IV, n)	N/A	16/81/44/20	5/37/28/16	11/44/16/4

Data are presented as mean ± standard deviation, unless otherwise indicated. FEV₁: forced expiratory volume in 1 second, FVC: forced vital capacity, IC: Inspiratory capacity, TLC: total lung capacity, RV: residual volume, DL_CO: diffusing capacity for carbon monoxide.
* p < 0.001 vs. controls, ^#p < 0.001 vs. ex-smokers with COPD, ^†p < 0.01 vs. ex-smokers with COPD

ISSN: 1465-993X