Received: 4 June 2020
Accepted: 7 December 2020
First Online: 6 January 2021
Ethics approval and consent to participate
: This study was approved by the Medical Ethics Committee of the First Affiliated Hospital of Xiamen University. Informed consent was waived because the study was conducted retrospectively and no interventions were applied.
: Not applicable (no details on individuals reported within the manuscript).
: The author(s) declare(s) that they have no competing interests.