Funding for this research was provided by:
Text and Data Mining valid from 2020-04-22
Received: 27 January 2020
Accepted: 13 April 2020
First Online: 22 April 2020
Ethics approval and consent to participate
: This study is part of the Watchtower project and has been approved by the Norwegian Centre for Research Data (SAK 31590). All data are anonymized, no patient identifiable data were recorded at any time, hence there was no need for informed consent from participants. The Regional Committee for Medical and Health Research Ethics did not consider it necessary to assess the study for approval (2012/1094/REC West).
: Not applicable.
: The authors declare that they have no competing interests.