Text and Data Mining valid from 2020-02-12
Received: 5 October 2019
Accepted: 29 January 2020
First Online: 12 February 2020
Ethics approval and consent to participate
: The local ethics committees of the participating organizations and institutions approved the study, which was performed consistently with the Helsinki declaration. Receiving approval for informed consent was waived be the Helsinki committee.
: Not applicable.
: The authors declare that they have no competing interests.