Statistical analysis
Statistical analysis was performed by the SPSS (version 21.0; SPSS Inc, Chicago, Ill, United States) software program. Numerical data were expressed as mean and standard deviation and compared between the three groups using the one-way ANOVA test. The categorical ones were expressed as numbers and percentages and compared between the three groups using the Chi-square test or Fisher's exact test. Post-hoc analysis (Tukey pairwise comparison) was also performed to compare each individual two groups. P-values less than 0.05 were considered significant. P was used to express the comparison between the three groups. P1, P2, and P3 were used to compare Groups R and S, Groups R and C, and Groups S and C, respectively, as shown in the following tables in the results section.