Text and Data Mining valid from 2018-06-18
Received: 12 February 2018
Accepted: 7 June 2018
First Online: 18 June 2018
Ethics approval and consent to participate
: The research project was approved by the South-East Regional Ethics Committee in Norway. Informed consent from participants were not required to obtain the dataset because the study was based on anonymized data from the patient registration.
: Not applicable.
: The authors declare that they have no competing interests.
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