Statistical analysis
The data were prospectively collected in a computerized database, and
then analyzed by Statistical Package for Social Sciences, version 22.0
(SPSS Inc., Chicago, III). All continuous variables were expressed as
the mean ± standard deviations, and the differences were tested for
significance using the Student t-test. The differences in categorical
variables were tested for significance with the χ2 or
Fisher exact test, as appropriate, and were presented as proportions
unless stated otherwise. p < 0.05 was considered to be
statistically significant in results.