Statistical analysis
REGRESSION
Descriptive statistics included the mean and standard deviation values for the normally distributed variables and median (minimum-maximum) for non-normally distributed variables. Due to the sample size < 50, the Shapiro-Wilk test was applied to assess the distribution.We applied a frequency analysis (the chi-square) to assess the contingency between the nominal and categorical variables. We applied MacNemar test for the paired nominal variables. The continuous variables were compared by Mann-Whitney U test, and for paired data we applied Wilcoxon signed-rank test. Spearman’s rank correlation coefficient was used to assess the association between the parameters of interest. Logistic regression analysis was used to assess the associations between circadian BP profile status (as the dependent categorical variable, dipping/non-dipping) and indices of AHI severity – AHI, ODI, mean SpO