Effect of dynamic position changes during colonoscope withdrawal: a meta-analysis of randomized controlled trials.

Background: Colonoscopies are considered to be the primary screening test and gold standard test for colorectal cancer. Position changes during colonoscope withdrawal are believed to be associated with an increased adenoma detection rate (ADR) and polyp detection rate (PDR). However, previous results conflicted, and this study aimed to elucidate the effectiveness of dynamic position changes during colonoscope withdrawal.
Methods: The relevant publications were identified by searching the medical databases. The primary outcomes were the ADR and PDR, which were pooled and analyzed. The secondary outcome was the withdrawal time. The studies that supplied the ADR and PDR for different segments of the colon were separated into subgroup analyses.
Results: Five randomized controlled trials were eligible for analysis. The total ADR was higher with dynamic position changes than with a static position (odds ratio, [OR] 1.34; 95% confidence interval [CI] 1.13-1.59; p < 0.001), with low evidence of between-study heterogeneity (I ₂  = 0%). Although the total PDR was slightly higher with dynamic position changes than with a static position (OR 1.23; 95% CI 0.88-1.73), there difference was not statistically significant (p = 0.22). The withdrawal time was only increased by 0.47 min (95% CI - 0.11 to 1.06) with dynamic position changes, without statistical significance (p = 0.11). The subgroup analysis showed that the ADR and PDR for the transverse colon were higher with dynamic position changes, with pooled estimates of ADR (OR 1.72; 95% CI 1.02-2.88; p = 0.04) and PDR (OR 1.79; 95% CI 1.08-2.96; p = 0.02).
Conclusion: Dynamic position changes during colonoscope withdrawal increased the total ADR; however, no obvious increase was found in the total PDR. The withdrawal time was not significantly prolonged with dynamic position changes. Subgroup analysis showed that the ADR and PDR in the transverse colon were obviously improved with dynamic position changes.