Table 3.

Multivariate analysis for predicting the risk of asthma exacerbation

	Univariate		Multivariatea
	Hazard ratio (95% CI)	P-value	Hazard ratio (95% CI)	P-value*
High serum sST2 level (> 18 ng/ml)	9.2 (2.4–34.7)	0.001	5.5 (1.4–21.5)	0.015
Blood neutrophiliab (> 6000 μl)	26.6 (7.9–100.9)	< 0.001	18.9 (4.8–74.4)	< 0.001

*P-values were calculated using Cox proportional hazard analysis

^aCorrelation coefficients: high serum sST2 level, 1.70; blood neutrophilia, 2.94, respectively

^bThe cut-off value for defining blood neutrophilia was optimized using the receiver operating characteristic curve analysis and calculating the Youden index

CI confidence interval