Statistical analysis
Descriptive statistics for categorical variables are reported as
absolute value and percentage, and continuous variables are shown as
mean and standard deviation. Categorical data were compared using the
chi-square test. Continuous variables were compared using the Wilcoxon
signed rank test.
We analyzed independent determinants of the additional procedure by
performing univariate logistic regression analysis and subsequent
multivariate logistic regression analysis, with the p values for entry
into and removal from the model set at 0.05 and 0.10, respectively. All
analyses were conducted with JMP version 13.0 (SAS Institute Inc., Cary,
NC, USA), and a p value of <0.05 was considered statistically
significant.