Received: 13 February 2019
Accepted: 17 June 2019
First Online: 1 July 2019
Ethics approval and consent to participate
: All personal data were pseudonymised. Participants gave their written consent and the Ethics Committee of the Hamburg Medical Association approved this study. The study was conducted according to good clinical practice based on the Helsinki declaration. The research is also registered within the German Registry of Clinical Studies under the DRKS-ID: DRKS00010819.
: Not applicable.
: The authors declare that they have no competing interests.