Received: 1 March 2019
Accepted: 22 June 2019
First Online: 10 July 2019
Compliance with ethical guidelines
: M. Eichler, B. Wehler, R. Buhl, J. Stratmann, M. Sebastian, H. Schmidberger, C. Kortsik, U. Nestle, H. Wirtz, T. Wehler and M. Blettner declare that they have no competing interests. M. Hechtner is an employee of Boehringer Ingelheim. S. Singer has received lecture fees from Bristol-Myers Squibb, Pfizer, and Boehringer-Ingelheim, all of them unrelated to this study.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (primary ethical approval from the Ethics Committee of Rhineland–Palatinate [number 837.376.14]) and with the 1975 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.