2.6. Statistical Analysis
IBM SPSS Win. Ver. 19.0 was used for statistical analysis of the data, with the significance level set at 5%. A two-sided test was used for all the tests. Descriptive statistical analyses were performed for the demographic characteristics, and the means and standard deviations or frequencies and percentages (for quantitative and qualitative data, respectively) were summarized. The homogeneity of demographic and clinical characteristics was tested according to the group using the two-sample 