Sample size and randomization method
WEST
Based on current research, the RABP in normal-weight people is approximately 80%, while that in people with high BMIs is less than 70%. Therefore, we assumed that the RABP for high-BMI individuals using 3 L PEG would be approximately 80%. The α value was set at 0.05, the β value was set at 0.2, and the lost to follow-up rate was set at 0.2. The sample size calculated by the professional sample size calculation tool (Medsci App 5.6.4) was 696 cases.Participants from each center were randomly and equally assigned to the 2 L and 3 L groups according to the block randomization schedule, with a block size of 4. The random number tables were independently generated by the China Evidence-based Medicine Center, West China Hospital of Sichuan University, using SAS 9.4 as the generation tool.