Received: 15 March 2020
Accepted: 18 May 2020
First Online: 5 June 2020
Ethics approval and consent to participate
: Verbal consent was obtained when doing follow up by phone call and since the data were anonymous, the requirement for written informed consent was therefore waived, and this study protocol was approved by the Ethical Committee of Human Experimentation in the First Affiliated Hospital of Sun Yat-sen University.
: Not applicable.
: All the authors declare no competing interests.