Statistical analysis
Continuous variables are presented as the mean and standard deviation (SD), and categorical variables are presented as frequencies and percentages. Categorical variables were analysed with the chi-square test and Fisher’s exact test when proportions were < 5. For data with a normal distribution, continuous variables were analyzed with Student’s t test for data with asymmetrical distribution, and nonparametric Mann‒Whitney tests and sign tests were used in asymmetric distributions. Statistical significance was set at 