Received: 25 May 2020
Accepted: 11 December 2020
First Online: 6 January 2021
Ethics approval and consent to participate
: This retrospective study was approved by Ethics Committee of Shandong University of Traditional Chinese Medicine. Because this is a retrospective study, patients were contacted by phone to given an oral consent. The ethics committee approved this procedure.
: Not Applicable.
: All authors do not have any possible conflicts of interest.