Received: 16 November 2019
Accepted: 24 January 2020
First Online: 10 February 2020
Ethics approval and consent to participate
: The present study was approved by the Institutional Review Board of Taichung Veterans General Hospital, Taiwan (CE14149B-3). Written informed consent was waived given that all of the data were de-identified.
: Not applicable.
: The authors of the study declare that they have no financial or commercial conflicts of interest with regards to this submission.