Statistical analysis
Distribution of data was analyzed using the Kolmogorov-Smirnov test. Categorical data are given as counts (n) and percentages (%). Continuous data were compared with unpaired t-test and Mann-Whitney U-test, respectively. Categorical data were compared with Chi2 and Fisher’s Exact test, respectively. Relationships between continuous variables were assessed by Spearman’s rank correlation tests. All reported p -values are two-sided, and a Greenhouse-Geisser corrected p-value was considered as level of significance (p <0.05) with a 95% confidence interval (CI). Statistical tests were performed with SPSS® Statistics Version 26.0.0.0 (IBM Corporation ©, Armonk, NY, USA) and figures designed by GraphPad Prism 8 for macOS Version 8.4.2 (GraphPad Software, LLC).
The study was approved by the Ethics Committee of the Medical University of Vienna (3rd August 2018) and complied with the principles as outlined in the declaration of Helsinki. Participants’ written consent was not required per Austrian Federal Act concerning Protection of Personal Data (DSG 2000).