Funding for this research was provided by:
German Federal Ministry of Health
Received: 23 March 2017
Accepted: 3 January 2018
First Online: 17 January 2018
Ethics approval and consent to participate
: The data-collection protocol was confirmed by the data-protection officer. Additional approval from an ethics committee was deemed not necessary, as no patient-identifying data were collected. According to the German Data Protection Act the study complies with the national guidelines, and no formal ethical committee approval was necessary (available underExternalRef removed)
: Not applicable
: Klaus Jansen is a member of the editorial board (Associate Editor) of this journal. All other authors declare that they have no competing interests.
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