Impact of bowel preparation with low-volume (2-Liter) and intermediate-volume (3-Liter) polyethylene glycol on colonoscopy quality: A prospective observational study

Background/Aims: Two-liter polyethylene glycol (PEG) is the most commonly used bowel-cleansing regimen in Taiwan, but its efficacy is unsatisfactory. The aim of this study was to compare 2-liter and 3-liter PEG in terms of their impact on colonoscopy quality among an average-risk population. Methods: Two-liter PEG was provided between August 2012 and May 2013, while 3-liter PEG was provided between June 2013 and March 2014. A split-dose regimen was provided for morning colonoscopy and a same-day regimen was provided for afternoon colonoscopy. The level of bowel cleansing was prospectively scored. Results: A total of 407 consecutive subjects completed the 2-liter regimen, and another 407 consecutive subjects completed the 3-liter regimen. The 3-liter group had a significantly higher rate of excellent or good preparations, equivalent to a Boston bowel preparation scale of ≥7, than the 2-liter group (90 vs. 73%, p < 0.0001). More subjects in the 3-liter preparation group compared with the 2-liter group had overall adenoma (70 vs. 54%, p < 0.0001), proximal adenoma (47 vs. 35%, p = 0.0006), sessile serrated adenoma (28 vs. 6%, p < 0.0001), and advanced adenoma (21 vs. 9%, p < 0.0001). Conclusions: Three-liter PEG provided better cleansing quality and higher adenoma detection rate than 2-liter PEG.