Received: 5 September 2017
Accepted: 15 January 2018
First Online: 8 February 2018
Ethics approval and consent to participate
: The Chang Gung Medical Foundation Institutional Review Board (no. 2016-01610B0) approved the study and waived the requirement for informed consent due to the retrospective nature of this study.
: Not applicable. This study did not contain any individual person’s data in any form (including individual details, image or videos).
: The authors declare they have no competing interests.
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