Received: 24 April 2019
Accepted: 5 July 2019
First Online: 17 July 2019
Ethics approval and consent to participate
: This study was approved by the Medical Ethics Committee of Shandong Provincial Qianfoshan Hospital (2017-S-015) and registered on the Chinese Clinical Trial Registry (ChiCTR1800015221).
: Not applicable.
: The authors declare that they have no competing interests.