*2.6. Statistical Analysis*

Statistical analysis was performed with MedCalc® vers. 19.2.1. The Chi-squared test and Student's *t*-test were used for categorical and continuous variables, respectively. Log-rank test was used to estimate the differences in Kaplan–Meier curves for independent risk factors. Results were considered statistically significant in the case of a *p*-value <0.05. Continuous variables are expressed as mean ± standard deviation of the mean.
