Statistical analysis
A Statistical analysis was performed using the software STATA/IC 14.2 version 2017. We provided a description of the set of data using frequency and percentage for categorical variables while continuous variables were described by measures of central tendency (mean or median, depending on whether the distribution was normal or not), and measures of dispersion (standard deviation, SD; interquartile range, IQR). The Shapiro–Wilk test was used to test the normality of the data.
Mainly, we use χ2 test or Fisher’s test for categorical variables as appropriate or Student t test or Mann Whitney test for continuous variables as appropriate.
We considered a 2-tailed p value less than 0.05 to be significant.