Features of cough variant asthma and classic asthma during methacholine-induced brochoconstriction: a cross-sectional study

Cough

Table 2 Univariate and multivariate regression analysis of appearance of wheezes

	Univariate analysis Correlation coefficient	P	Wheezes Standardized partial regression coefficient	F value
Disease	0.34	0.0002	not entered	< 4.0
Blood eosinophils (number/μl)	0.11	0.35	not entered	< 4.0
Atopy	-0.05	0.60	not entered	< 4.0
Baseline FEV1/FVC (%)	-0.31	0.001	-0.31	9.2
Smoking	0.08	0.39	not entered	< 4.0
Log Dmin (units)	-0.30	0.001	-0.33	10.7
SRrs (cmH₂O/L/sec/min)	0.28	0.003	not entered	< 4.0

Adjusted R² = 0.22, p < 0.0001 for the multivariate analysis of appearance of wheezes. Wheezes, atopy, and smoking status are rated as 0 for absent and 1 for present. Disease is labeled as 0 for cough variant asthma and 1 for classic asthma. F value is a measure of the extent to which a variable makes a unique contribution to the prediction of the dependent variable. Dmin, cumulative dose of inhaled methacholine at the inflection point, where which respiratory resistance begins to increase. SRrs, slope of the methacholine dose-response curve for respiratory resistance.