Received: 16 January 2019
Accepted: 6 August 2019
First Online: 20 August 2019
Ethics approval and consent to participate
: Ethical approval was obtained by the ethics committee of the medical faculty of the Heinrich-Heine-University of Düsseldorf. All study participants gave their written informed consent to participate in the study.
: Not applicable.
: The authors declare that they attempted to present a well-balanced account of the findings. However, being employed (JW, TM, PA, AL), a member of the teaching staff (TM, PA, AL) or a medical student (SS) at the medical faculty of the Heinrich-Heine-University of Düsseldorf may have induced some bias which we are not aware of.