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.