Received: 14 April 2020
Accepted: 23 June 2020
First Online: 7 July 2020
Ethics approval and consent to participate
: This retrospective database analysis study was approved by the institutional review board of the University of Leipzig Ethics Committee (ethical committee application number: 078-14-10032014), and the requirement to obtain informed consent was waived.
: All authors consent to the publication.
: The authors declare no competing interests.