Statistical analysis
Statistical calculations were performed using the SPSS 19.0 (IBM Inc.,
Chicago, IL) software. The significance of differences between the
asthmatic and healthy children in their categorical variables was
estimated by the χ 2 test and continuous
variables (for example, age, BMI, Δ%FEV1) by the t test
or ANOVA analyses. Receiver operating characteristic (ROC) curve with
analysis of differences in the area under curves (AUC) was used to
estimate the diagnostic accuracy. Furthermore, asthmatic subjects with
repeated data were further divided into three groups according to the
levels of eicosanoid species during exacerbation, i.e. the top 30%,
middle 40%, and bottom 30%. A two-way mixed-design analysis of
variance (i.e. split-plot ANOVA) was performed for analyzing the effect
of stratified eicosanoid levels (top 30% vs. middle 40% vs. bottom
30%) and phases (active exacerbation vs. convalescence).