Statistical analysis
Continuous variable data were expressed as mean ± standard deviation (SD), and compared values were analyzed using the independent t-test. Non-normally distributed continuous data, which were analyzed using the Mann-Whitney U test, are presented as medians (interquartile range [IQR], 25-75%). Categorical data were expressed as numbers and percentages and analyzed using Pearson’s chi-square test with continuity correction or Fisher’s exact probability method. All statistical calculations were performed using SPSS (Statistical Product and Service Solution) version 10.0 (IBM, Chicago, Illinois, US), and 