Statistical Analysis
SPSS statistics Version 22.0 (International Business Machines (IBM)
Corporation) was employed for data analysis. Enumeration data were
expressed as percentages and the χ2 test was used for comparisons
between groups. Measurement data conforming to the normal distribution
were expressed as the mean ± standard deviation (SD) and the t-test was
used to make comparisons between two groups. The median [interquartile
range (IQR) M(P25-P75)] was used for
measurements of data not conforming to the normal distribution and the
rank-sum test was used to make comparisons between two groups. Count
data were expressed by rate or constituent ratio and chi-squared testing
was performed. A value of P < 0.05 was considered
statistically significant.