Table 3.

Univariate and multivariate regression analyses of appearance of cough

	Univariate analysis Correlation coefficient	P	Cough Standardized partial regression coefficient	F value
Disease	-0.20	0.036	-0.27	6.2
Blood eosinophils (number/μl)	-0.12	0.27	Not entered	< 4.0
Atopy	0.02	0.83	not entered	< 4.0
Baseline FEV1/FVC (%)	0.11	0.25	not entered	< 4.0
Smoking	-0.10	0.30	not entered	< 4.0
Log Dmin (units)	0.09	0.33	not entered	< 4.0
SRrs (cmH2O/L/sec/min)	-0.02	0.87	not entered	< 4.0

Adjusted R² = 0.06, p = 0.015 for the multivariate analysis of appearance of cough. Cough, 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.