Comparing right colon adenoma detection rate during water exchange and air insufflation: a double-blind randomized controlled trial

Background Randomized controlled trials (RCTs) have reported that water exchange (WE) produced the highest adenoma detection rate (ADR) but did not evaluate right colon adenoma detection rate (rADR) as a primary outcome and only one of the trials employed blinded colonoscopists. The aim of our study was to determine whether, compared with air insufflation, WE significantly increases rADR and right colon serrated lesion detection rate (rSLDR) and decreases adenoma miss rate (rAMR). Methods This prospective, double-blind RCT was conducted at a regional hospital in Taiwan between December 2015 and February 2020. Standard WE and air insufflation were performed. After cecal intubation, the second blinded endoscopist examined the right colon and obtained rADR (primary outcome) and rSLDR. Then, the primary colonoscopist reinserted the scope to the cecum with WE in both groups and performed a tandem examination of the right colon to obtain rAMR. Results There were 284 patients (50.9% male, mean age 58.9 ± 9.4 years) who were randomized to WE ( n = 144) or air insufflation ( n = 140). The baseline characteristics were similar. The rADR (34.7% vs. 22.3%, p = 0.025), Boston Bowel Preparation Scale scores (mean, 2.6 ± 0.6vs. 2.2 ± 0.6, p