Received: 31 January 2019
Accepted: 17 May 2019
First Online: 7 June 2019
Ethics approval and consent to participate
: Approval from an ethics committee, as well as consent to participate were not required since this study was retrospective. However, we obtained the permission from the IT department in charge of the patients’ files to access the raw data.
: Not applicable.
: The authors declare that they have no competing interests.