Impulse oscillometry for detection of small airway dysfunction in subjects with chronic respiratory symptoms and preserved pulmonary function

Table 3 Correlation between spirometry and IOS parameters in subjects with chronic respiratory symptoms and PPF (n = 209)

IOS parameter	FEV₁ (% predicted)		FVC (% predicted)		FEV₁/FVC		FEF_25–75% (% predicted)		FEF_50% (% predicted)		FEF_75% (% predicted)
IOS parameter	r	P value	r	P value	r	P value	r	P value	r	P value	r	P value
R5	− 0.15	0.033	0.04	0.526	− 0.23	0.001	− 0.37	< 0.001	− 0.37	< 0.001	− 0.37	< 0.001
R20	− 0.12	0.092	0.01	0.923	− 0.08	0.243	− 0.26	< 0.001	− 0.28	< 0.001	− 0.23	0.001
R5–R20	− 0.07	0.293	0.09	0.208	− 0.33	< 0.001	− 0.27	< 0.001	− 0.23	0.001	− 0.35	< 0.001
X5	0.13	0.068	0.09	0.211	− 0.02	0.791	0.19	0.005	0.19	0.005	0.16	0.018
AX	− 0.17	0.013	− 0.05	0.471	− 0.16	0.020	− 0.30	< 0.001	− 0.28	< 0.001	− 0.29	< 0.001
Fres	− 0.13	0.069	0.03	0.623	− 0.28	< 0.001	− 0.30	< 0.001	− 0.28	< 0.001	− 0.31	< 0.001

ISSN: 1465-993X