Statistical analysis
Continuous variables were expressed as mean ± standard deviation or
median (interquartile range). Differences in baseline characteristics
were analyzed using the Student’s t -test for parametric data and
the Mann–Whitney U test for non-parametric data. Categorical
variables were compared using chi-square or Fisher’s exact tests. The
prognostic value of each factor was first evaluated using a univariate
logistic regression analysis. Factors with p-values < 0.05 in
the univariate analysis were entered into a multivariate logistic
regression model using a forward stepwise method to identify independent
predictors. Statistical significance was set at p <0.05.