Statistical analyses
REGRESSION, SECONDARY
According to the intention-to-treat principle, we used full analysis data set to analyze the primary outcome. The full analysis set (FAS), including all patients underwent randomization and at least once training and with once measurement after surgery, was used for analysis of primary and secondary outcome. Normal distributed continuous data were presented as mean ± standard deviation (SD), and difference between groups was tested by using student t-test. Skew-distributed data was presented as median and the 25th percentile and 75th percentile, and between-group differences were tested by using Mann-Whitney test. Categorical variables were described as number (n) and percentage (%) and chi-square test or Fisher’s exact test was used for comparisons between the two groups. Multivariable logistic regression model was performed to identify independent associated factors of ED. All statistical analyses were conducted by using IBM SPSS Statistics (Version 20.0, IBM, Armonk, NY, USA). Two-sided P-value less than 0.05 indicated statistical significance.