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A Randomized Controlled Trial Comparing Colonoscopic Enema With Additional Oral Preparation as a Salvage for Inadequate Bowel Cleansing Before Colonoscopy

Yang, Hyo-Joon MD, PhD*; Park, Dong Il MD, PhD*; Park, Soo-Kyung MD, PhD*; Kim, Sunyong MD; Lee, Taeheon MD; Jung, Yunho MD, PhD; Eun, Chang Soo MD, PhD§; Han, Dong Soo MD, PhD§

Journal of Clinical Gastroenterology: September 2019 - Volume 53 - Issue 8 - p e308–e315
doi: 10.1097/MCG.0000000000001087
ONLINE ARTICLES: Original Articles

Goals: The goal of this study was to evaluate the noninferiority of colonoscopic enema to additional oral preparation in salvage bowel cleansing for inadequate preparation for a morning colonoscopy.

Background: Colonoscopic enema, administering additional cathartics into the right colon through the colonoscope accessory channel, is suggested to rescue poor bowel preparation for a colonoscopy but lacking comparative study.

Study: In this prospective, randomized, actively-controlled, parallel group, noninferiority trial, consecutive outpatients and health checkup recipients aged from 19 to 70 years with inappropriate bowel preparation during an elective colonoscopy were enrolled to receive either a colonoscopic enema of 1 L polyethylene glycol (PEG) (enema group) or additional oral intake of 2 L PEG (oral group). The primary endpoint was the proportion of adequate bowel preparation evaluated using the Boston Bowel Preparation Scale.

Results: Overall, 131 participants were randomized. Adequate bowel preparation was achieved in 53% (35/66) of the enema group, which was significantly inferior to the oral group (81.5%; 53/67) with a difference of −28.5% (95% confidence interval, −44.1, −12.9; P=0.001). The largest difference in the proportion of adequate bowel preparation was observed in the right colon (57.8% in the enema group vs. 86.9% in the oral group; P<0.001), followed by the transverse colon (85.9% vs. 98.4%; P=0.017) and the left colon (90.6% vs. 96.7%; P=0.274).

Conclusions: The colonoscopic enema of 1 L PEG was inferior to the additional oral ingestion of 2 L PEG regarding efficacy as a salvage bowel preparation in adults with inadequate bowel cleansing for colonoscopy.

*Department of Internal Medicine and Gastrointestinal Cancer Center, Division of Gastroenterology

Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul

Department of Internal Medicine, Division of Gastroenterology, Soonchunhyang University College of Medicine, Cheonan

§Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Republic of Korea

The authors declare that they have nothing to disclose.

Address correspondence to: Dong Il Park, MD, PhD, Division of Gastroenterology, Department of Internal Medicine and Gastrointestinal Cancer Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 29 Saemunan-ro, Jongno-gu, Seoul 03181, Republic of Korea (e-mail:

Received March 3, 2018

Accepted May 22, 2018

Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.