Received: 22 May 2019
Accepted: 30 August 2019
First Online: 6 September 2019
Ethics approval and consent to participate
: The study was approved by the local Ethics Committee of the Charité-Universitätsmedizin Berlin (number: EA2/091/13) and registered at ExternalRef removed (NCT02176603). Written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that there are no competing interests.