Statistical Analysis
After the normality test through the Shapiro-Wilk test, a t-test was
performed for calculating the differences in the numerical variables
between two normally distributed groups and Mann-Whitney U test for
non-normally distributed data. And the Kruskal-Wallis test was applied
among three non-normally distributed groups. For the classified
variables, the chi-square test or Fisher exact test was carried out. All
analyses were completed via statistical software SPSS 25.0 (SPSS Inc.,
Chicago, Ill., USA) and a two-tailed P < 0.05 was
treated as statistical significance.