Received: 4 June 2018
Accepted: 6 February 2019
First Online: 13 February 2019
Ethics approval and consent to participate
: All participants received written information sheets and provided verbal informed consent in this study. It aimed to minimize the number of document to protect participants’ personal information. It is a common practice locally and the method was approved by the Kowloon Central / Kowloon East Research Ethics Committee of Hospital Authority (Reference number: KC/KE-14-0065/FR-1).
: Not applicable.
: The authors declare that they have no competing interests.
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