Received: 15 December 2018
Accepted: 18 March 2019
First Online: 27 March 2019
Ethics approval and consent to participate
: The Institutional Review Board of National Cheng Kung University Hospital approved this study (A-EX-104-045). Informed consent was not required because the datasets were devoid of personally identifiable information.
: Not applicable.
: The authors declare that they have no competing interests.
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