Statistical analysis
Demographic characteristics were assessed as counts and percentages for categorical variables and standard measures (median and interquartile range (IQR)) for continuous variables. Comparisons of paired measurements were performed using a non-parametric Wilcoxon matched-pairs signed-rank test. All statistical analyses were performed with GraphPad Prism version 5.01 software (GraphPad Software, La Jolla, CA, USA). A p-value < 0.05 was considered statistically significant.