Statistical Analysis
Statistical analyses were performed using SPSS (version 19.0 program for
Windows; SPSS Inc., Chicago, IL, USA). Categorical datas were presented
as numbers (percentage) and tested using the Chi-square test or Fisher’s
exact test. Continuous variables with normal distribution were presented
as mean ± SD (standard deviation) and tested with a paired t-test. The
chi-square test was used to compare categorical variables between the
groups. Correlations between numerical variables were evaluated using
Pearson’s or Spearman’s correlation analysis. We selected correlation
strength by an absolute correlation
|r|>0.2. P-values based on two-sided
tests were considered as statistically significant at less than 0.05.