Improving Trainee Colonoscopy Performance By Investigating The Withdrawal Time From Individual Colonic Segments: A Single-Center Observational Study

Background: The colonoscopy withdrawal time (WT) and adenoma detection rate (ADR) are widely used quality indicators for colonoscopy. However, no study has investigated the appropriate colonoscopy WTs of individual colonic segments that will allow trainees to achieve a higher ADR. Thus, we analyzed for the first time the relationship between colonoscopy WT and the ADR/polyp detection rate (PDR) in the proximal, left-sided and entire colon among trainees.Methods: This retrospective study involved 611 consecutive patients who underwent colonoscopy from March 2018 to March 2019 performed by 6 trainees in the Endoscopy Center of Shanghai General Hospital. The WTs for the individual colonic segments and any significant findings of colonoscopies were retrospectively retrieved from the trainees' records and verified in the endoscopy center database. ADR/PDR was defined as the number of colonoscopies detecting at least 1 polyp/adenoma divided by the total number of colonoscopies. Comparisons of PDR and ADR between the 2 groups were conducted using chi-square test. Multilevel analysis was performed to consider individual differences among the 6 trainees. Multilevel binary logistic regression analysis was performed to analyze the factors that influenced the PDR, ADR and advanced adenoma detection rate (AADR) for the entire colon, and trainee status was included as a random effect.Results: The mean WTs were 4.20 +/- 1.09, 4.27 +/- 1.12, and 8.48 +/- 1.87 minutes for the proximal, left-sided, and entire colon, respectively. A longer WT [odds ratio (OR) 1.499, 95% confidence interval (CI): 1.381-1.628, P<0.001; OR 1.409, 95% CI: 1.265-1.569, P<0.001, respectively] was significantly associated with a higher PDR and ADR. The PDR (P<0.001) and ADR (P<0.001) were significantly higher when the WT was >4 minutes than when the WT was minutes in both the proximal and left-sided colon, while the PDR (P<0.001) and ADR (P<0.001) were significantly higher when the WT was >8 minutes in the entire colon.Conclusions: In order to improve trainee colonoscopy performance, trainees were recommended to have WTs of at least 4 minutes in the proximal colon, 4 minutes in the left-sided colon and 8 minutes in the entire colon during negative screening colonoscopies.