Clinical characterization and outcomes of impulse oscillometry-defined bronchodilator response: an ECOPD cohort-based study

Table 4 Association between acute respiratory exacerbations, decline in lung function and IOS-BDR in overall participants

Outcome	Without IOS-BDR	With IOS-BDR	Unadjusted		Adjusted
Exacerbations*			Odds ratio (95% CI)	P Value	Odds ratio (95% CI)^†	P Value
Any respiratory exacerbations (n=397)	177 (55.5)	46 (59.0)	1.15 (0.70, 1.91)	0.578	0.77 (0.42, 1.41)	0.399
Moderate to severe exacerbations (n=390) ¶	122 (39.0)	39 (50.6)	1.61 (0.97, 2.65)	0.064	1.12 (0.61, 2.05)	0.708
*Annualized lung function*^‡			Mean difference (95% CI)	P Value	Mean difference (95% CI)^§	P Value
Post-bronchodilator Spirometry	N=332	N=80
Decline in FEV_1, mL/y	-38.6 ± 7.6	-56.7 ± 15.3	-18.1 (-49.0, 12.9)	0.251	-12.9 (-131.6, 105.7)	0.831
Decline in FVC, mL/y	12.7 ± 29.7	-198.7 ± 59.7	-209.1 (-329.7, -88.5)	< 0.001	-209.3 (-339.3, -79.4)	0.002
Decline in FEV₁/FVC, %/y	-0.5 ± 0.2	-1.6 ± 0.4	-1.0 (-1.9, -0.2)	0.013	-1.0 (-2.0, 0.03)	0.057

IOS, Impulse oscillometry; BDR, bronchodilator response; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; COPD, Chronic Obstructive Pulmonary Disease
* Logistic regression model; exacerbations at 2-year follow-up as binary variable 0 vs. ≥ 1
† Adjusted for age, sex, BMI, smoking status, pack-years, family history of respiratory diseases, occupation exposure, biomass exposure, history of asthma, exacerbations in previous year and baseline pre-bronchodilator FEV₁.
‡ Linear mixed-effects model
§ Adjusted for age, sex, BMI, smoking status, pack-years, family history of respiratory diseases, occupation exposure, biomass exposure, history of asthma and baseline lung function (FEV₁, FVC, and FEV₁/FVC).
¶ 7 pariticipants without Moderate to severe exacerbations data

ISSN: 1465-993X