Randomization, assignment, and blinding
The study used a block randomization method with a block length of four. Eligible children (and their parents) were equally randomized to a control group and an intervention group by using a random assignment table (with randomization information including random seed, length, and the number of blocks) generated by an independent statistical professional based on the block randomization methods. Patient assessment and data collection were completed by a trained full-time research nurse. The investigators who implemented the intervention based on randomized information and performed all the assessments and the statistical analysts were blinded to the grouping information.