Text and Data Mining valid from 2019-10-28
Received: 11 July 2019
Accepted: 10 October 2019
First Online: 28 October 2019
Ethics approval and consent to participate
: This study was performed in accordance with the Declaration of Helsinki and was approved by the Institutional Review Board of the University of Hong Kong / Hospital Authority (UW 18–229).
: Not applicable as there is no identifiable material in this manuscript.
: The authors declare no that they have no competing interests.