2.3 Statistical analysis
The SPSS21.0 software (IBM) was used for statistical analysis. The Shapiro-Wilk test was used to test the data’s normality. Data with a normal distribution were presented as mean and standard deviation (SD), with group comparisons analyzed using the Student’s t-test. Data with normal distribution at multiple time points were analyzed using repeated measures analysis of variance (ANOVA). Data with non-normal distribution were expressed as the median (quartiles). The Mann-Whitney U test was used for intergroup comparisons. Data with non-normal distribution at multiple time points were analyzed using the Generalized Estimating Equations (GEE). The categorical data were shown as numbers (%) and were analyzed using the chi-square test or Fisher’s exact test as appropriate. Adjustment for multiple testing was done using Bonferroni or LSD. A two-sided test P-value less than 0.05 was considered statistically significant.