Received: 19 October 2018
Accepted: 24 June 2019
First Online: 25 July 2019
Ethics approval and consent to participate
: Approval for the study was obtained from the Tallinn Medical Ethics Committee and Estonian Data Protection Inspectorate. Consent to participate in a retrospective study is not required if approval from Estonian Data Protection Inspectorate is obtained.
: Not applicable.
: The authors declare that they have no competing interests.