Received: 25 February 2021
Accepted: 14 May 2021
First Online: 5 June 2021
: This study was conducted in accordance with the Declaration of Helsinki (1975), which obtained the approval from the Ethics Committee of Weihai Central Hospital Affiliated to Medical College of Qingdao University (approval number: WCH-A21; 2017.7.12, Shandong Province, China).
: Not applicable.
: The authors declare that they have no competing interests.