Statistical analysis
Descriptive data are expressed as proportions, and continuous variables as mean plus standard deviation. Continuous variables with normal distribution were compared using the paired t-test. Univariate and multivariate logistic regression modelling identified factors associated with treatment response. A final model was constructed using a stepwise method with backward selection; p values < 0.15 in univariate analysis were set for the entry of variables. The Linear-by-Linear association test was used to analyze trends for categorical variables. Two-sided p values < 0.05 were considered to indicate significance. All analyses were performed using the SPSS ver. 24.0 (IBM Corporation, USA) software.