Received: 18 July 2019
Accepted: 11 December 2019
First Online: 30 December 2019
Ethics approval and consent to participate
: This study was approved by the Ethics Commission of Cologne University’s Faculty of Medicine (Ref No. 19–1404).According to the Ethics Vote, the collection of consent forms was not required.
: Not applicable.
: The authors declare that they have no competing interests.