Statistical analysis
All statistical analyses were performed using SAS®guide Enterprise software (SAS Institute, Cary, NC, USA). Missing data
were not replaced. Continuous variables were described as the number of
observed data, mean and standard deviation of normally distributed
values, or median (interquartile range). Categorical variables
were described as the patients’ size and percentage in each category.
For inferential statistics, P-values < 0.05 were considered
significant. Tests were two-tailed. Reproducibility was tested using a
Pearson correlation between exposure days.