Ethical Considerations
This study was approved by the Human Research Ethics Committee of the General Hospital of Ningxia Medical University (ID2018-325). All participants provided formal written informed consent, which the committee approved. All names were replaced with codes during electronic data entry to preserve the anonymity and privacy of the participants. The questionnaires were locked in a filing cabinet at the trial hospital. The data were analyzed in an Excel (Microsoft Corp) spreadsheet and stored in a password-protected secure office computer of a researcher. Data security was guarded by firewalls and other security mechanisms imposed by the networked computers at the trial hospital. There was no compensation for study participation.