Statistical analysis
The normal distribution of continuous variables was examined using the
Shapiro–Wilk test. Continuous data were expressed as mean values ± the
standard deviation if normally distributed. Categorical data were
presented as a percentage. The Student’s two-sample t-test or the
Man–Whitney U test was performed to compare continuous variables.
Fisher’s exact test or the Chi-square test was used to compare
categorical data. To compare more than two variables, we used the
one-way variance analysis or the Kruskal–Wallis test as an extension of
the Student’s t-test. Univariate analysis was performed to assess the
predictors of clinical outcomes. The predictors of 12-month mortality
were estimated by multivariate regression analysis. Cumulative survival
incidence was compared using the Log-rank test between the groups and
presented by the Kaplan–Meier curve. A ROC analysis was performed to
determine independent predictors’ sensitivity and specificity for
unfavourable outcomes and mortality with defined cut-off values.
Two-tailed p-values were considered to be significant if ranging below
0.05. Statistics were performed using SPSS (PASW statistic, Version
25.0.0.0, SPSS Inc., Chicago, Illinois, USA) and MedCalc Statistical
Software (Version 19.2, MedCalc Software Ltd, Ostend, Belgium).