Water exchange reduces right colon adenoma, serrated polyp miss rates

Water exchange (WE) significantly lowers right colon adenoma miss rate (rAMR) and right colon serrated polyp miss rate, according to a study.

“The unblinded consecutive group observational data showed that WE significantly decreased rAMR,” the investigators said. “The unblinded data are limited by potential bias.”

To test this hypothesis, 262 consecutive patients aged ≥45 years were randomized to undergo insertion with WE (n=131) or carbon dioxide (CO2; n=131). The investigators performed withdrawal and polypectomy with CO2 in both groups to the hepatic flexure. The colonoscope was then reinserted to the cecum.

A second colonoscopist re-examined the right colon. This colonoscopist was unaware but made a guess of the initial insertion method. RAMR was determined by the number of additional adenomas divided by the total number detected in both examinations.

Demographic variables were comparable in both groups, but the body mass index was significantly higher among patients in the WE group.

WE significantly decreased rAMR (18.0 percent vs 34.6 percent; p=00025) and right colon serrated polyp miss rate (17.4 percent vs 39.3 percent; p=0.002) compared with CO2.

In multivariate logistic regression analysis, WE independently predicted rAMR (odds ratio [OR], 0.42, 95 percent confidence interval [CI], 0.21–0.86), as did ≥2 adenomas in the right colon (OR, 2.35, 95 percent CI, 1.17–4.76).

Of note, rAMR was neither associated with demographic and procedure variables nor with whether the second colonoscopist guessed the insertion method correctly or not.

“The randomized controlled trial validated unblinded observational data showing that WE significantly decreased rAMR and right colon serrated polyp miss rate,” the investigators said.