Received: 12 May 2019
Accepted: 30 August 2019
First Online: 18 September 2019
Ethics approval and consent to participate
: This study was performed in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Tongren Hospital, Beijing, China (approval number TRCKY-033). Informed consent was obtained from all the subjects after the aims and nature of the study were explained to the participants. Written informed consents were obtained from all patients participating in the investigation.
: The authors declare that they have no competing interests.