1.5 Statistical analysis
Continuous variables were presented as median (interquartile range, IQR)
and compared with the Kruskal-Wallis test between different groups;
categorical variables were presented as numbers (%), and
comparisons between different groups
were done by the χ² test or Fisher’s exact test. A two-sided α of less
than 0.05 was considered statistically significant. Statistical analysis
was done using SPSS statistical software version 19.0 (SPSS Inc.,
Chicago, IL, USA).