Received: 31 October 2017
Accepted: 18 December 2018
First Online: 27 December 2018
Ethics approval and consent to participate
: The study was approved by the local ethics committee,the Medical Research Ethics Committee of the First Affiliated Hospital of Zhengzhou University. The interviewer (before trained) gave the patients detailed information about the study, and the interview was carried out after receiving informed consent from the patients. Patients in this study had a detailed knowledge of the disease and agreed to participate in the investigation.
: Not applicable. There is no personal information provided in the manuscript.
: The authors declare that they have no competing interests.
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