2.3 Data analysis
Statistical analysis was performed using IBM®SPSS® Statistics version 26. Categorical variables are presented as frequencies and percentages, and continuous variables as means and standard deviations if normally distributed, or medians and interquartile ranges for variables with skewed distributions. Normal distribution was verified through the Kolmogorov-Smirnov test or skewness and kurtosis (maximum tolerated interval of -1 to 1).
Bivariate analysis was performed by using χ2 test (or Fisher exact test as appropriate) for categorical variables and t test for continuous variables. Using logistic regression, odds-ratio (OR) were determined. All reported p values are two-tailed with values inferior to 0.05 indicating statistical significance.
We also proceeded to analyse the sub-group with a severely prolonged QTc interval as defined by values greater than 500ms.
The study was approved by the local ethics committee. Due to the retrospective nature of the study, informed consent from patients was waived.