Data collection and quality control
CRF
CRF
The original data were recorded in paper case report form (CRF) and then filled in a spreadsheet. An independent investigator checked the original data to ensure the consistency of CRF and spreadsheet. Only the principal investigators and clinical investigators were qualified to review the data. Before the start of trial, all involved researchers underwent training to guarantee the full understanding of study protocol, research process and CRF-filling. Additionally, once the eligible participants were enrolled, full communication about possible benefits and risks were made and a comfortable treatment environment was provided to ensure participants’ compliance. For participants with poor compliance, investigators contacted them by phone to acquire the outcome data, inquire about possible reasons for non-compliance, and encourage them to complete the study.