Table 4.

Factors associated with fixed airway obstruction in patients with severe asthma

	Univariate analysis		Multivariate analysis
	p-value	Crude OR (95% CI)	p-value	Adjusted OR (95% CI)
Smoking more than 5 pack-years	< 0.001	3.8 (2.1-7.0)	0.015	6.6 (1.4-30.1)
Asthma more than 15 years	0.064	1.8 (1.0-3.4)	0.028	5.4 (1.2-24.4)
Absence of rhinosinusitis	0.014	2.0 (1.2-3.4)	0.023	3.8 (1.2-12.3)
Age ≥50 years	< 0.001	3.2 (1.9-5.6)	0.632	1.6 (0.2-10.4)
Onset age < 40 years	0.018	0.5 (0.3-0.9)	0.893	1.1 (0.2-8.2)
Male sex	< 0.001	2.7 (1.6-4.7)	0.907	1.1 (0.3-4.9)
Presence of atopy	0.069	0.5 (0.2-1.1)	0.097	0.4 (0.1-1.2)

Abbreviations: OR, odds ratio; CI, confidence interval