Funding for this research was provided by:
Innovation committee at the federal joint committee (01VSF17026)
Received: 6 March 2019
Accepted: 19 June 2019
First Online: 11 July 2019
Ethics approval and consent to participate
: The DAVOS study has been approved by the ethics committee of the Goethe University of Frankfurt am Main, Germany (reference 129/18 and conforms to the Declaration of Helsinki (Version Fortaleza 2012).
: Not applicable.
: The authors declare that they have no competing interests.