Text and Data Mining valid from 2019-12-01
Received: 16 April 2019
Accepted: 16 November 2019
First Online: 6 December 2019
Ethics approval and consent to participate
: The study was approved by the institutional review board (Ethics Committee of the Charité university hospital, Berlin, identifier EA1/209/18).
: Not applicable.
: The authors declare that they have no competing interests.