Received: 21 May 2018
Accepted: 11 June 2019
First Online: 4 July 2019
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of the First Affiliated Hospital of Guangzhou Medical University. Written informed consent from study participants were not feasible since this is a retrospective study and the patient database is available in the Hospital. Thus, the local ethics committee waived the need for written informed consent from the participants and permitted to access the law data. Patient’s data were de-identified by authors before analysis.
: Not applicable.