Statistical analyses
Descriptive data are presented either as mean ± standard
deviation (SD), or as medians with interquartile range
(IQR). Percentages are given for categorical variables.
The Student’st-test or the Mann–Whitney test were
used for comparisons between two groups, and the
Kruskal-Wallis test or one-way analysis of variance was
performed when comparing several groups. Survival was
analysed from the time of entry into the study until
death, and also after excluding patients with shorter
observation period than 2 months.