Anticipating undiagnosed asthma in symptomatic adults with normal pre- and post-bronchodilator spirometry: a decision tool for bronchial challenge testing

Table 2 Multivariable analysis of risk factors associated with Asthma for subjects responding “Yes” to the GAS question ^a

Variable	Odds Ratio	Two-sided P-value	95% Conf. Interval
Female	4.558	0.003	(1.686, 12.322)
Pre bronchodilator FEV1% predicted ^b	0.940	0.010	(0.896, 0.985)
FEV1% response to bronchodilator ^c	1.190	0.019	(1.029, 1.376)
Constant	49.023

^aGlobal Asthma Symptoms (GAS) question; “When you exercise, work hard physically, or when you inhale cold and dry air during the winter, do you ever cough, feel tightness in your chest, have wheezing or whistling or start to be out of breath?”
^bCalculated using GLI reference values
^cFEV1% response to bronchodilator (traditional calculation) = (Post-bronchodilator FEV1 – Pre-bronchodilator FEV1)/ Pre-bronchodilator FEV1

ISSN: 1471-2466