Received: 18 December 2019
Accepted: 20 February 2020
First Online: 11 March 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of the Hualien Tzu Chi Hospital Research Ethics Committee (approval no. IRB107-194-B), and the need for informed consent was waived.
: Not applicable
: The authors declare that they have no competing interests.