High-Volume Split-Dose Versus Low-Volume Split-Dose Polyethylene Glycol Preparations: Which Is a Better Choice?

Abstract

We read with great interest the article written by Barkun et al.1Barkun A.N. et al.Clin Gastroenterol Hepatol. 2022; 20: e1469-e1477Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar This large national randomized clinical trial emphasized high-volume split-dose polyethylene glycol (PEG) (2 L + 2 L) provides statistically greater yet clinically comparable results for adequate bowel preparation compared with low-volume split-dose PEG (1 L + 1 L). This result, which is consistent with our conventional notion, will help us better explain the choice of colonoscopy preparation to our patients, individualizing them to patients’ preferences. However, we wish to further emphasize several issues. First, obesity is a recognized risk factor for failed bowel preparation in previous studies.2Fayad N.F. et al.Clin Gastroenterol Hepatol. 2013; 11: 1478-1485Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar In addition, obesity is becoming a global epidemic, and obese patients represent an increasingly higher proportion of the patients undergoing colonoscopy. Obesity is also a well-established risk factor for advanced neoplasia and colorectal cancer, necessitating a high-caliber examination for obese individuals. However, no study has specifically demonstrated the relationship between the quality of bowel preparation and the dosage of laxatives in patients with different body mass indexes (BMIs). The current guidelines have not recommended standard regimes for people with high BMI either.3Hassan C. et al.Endoscopy. 2019; 51: 775-794Crossref PubMed Scopus (132) Google Scholar Therefore, we sincerely hope that this prospective multicenter study could further analyze the relationship between BMI and the dosage of preparation to help better choose a bowel preparation program for this population. Second, this study concluded the non-inferiority hypothesis for low-volume split-dosing was rejected because adequate bowel cleanliness was significantly greater for the high-volume split-dose group (90.1% vs 88.1%, respectively; P = .02), although low-volume split-dose regime resulted in fewer symptoms, with greater willingness to repeat (66.9% versus 91.9%; P < .01) and tolerability (7.3 ± 2.3 vs 8.1 ± 1.9; P < .01). However, high-volume split-dosing was not associated with adequate bowel preparation (odds ratio, 1.37; 0.99–1.89) in multivariable analyses. The conclusion of this article also seems to ignore the similar detection rates of polyps, adenomas, and even advanced neoplasia between low- vs high-volume split-dose regimens. Actually, adequate bowel cleansing works by detecting colorectal neoplasia and minimizing the risk of missed lesions and post-colonoscopy colorectal cancer. Spadaccini et al4Spadaccini M. et al.Clin Gastroenterol Hepatol. 2020; 18: 1454-1465.e14Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar demonstrated there was no significant difference in the adequacy of bowel preparation and adenoma detection rate between low- vs high-volume split-dose regimens on the basis of a systematic review of 17 randomized controlled trials. In addition, the former was better tolerated, with superior compliance. We are concerned that this study might cause a medical dilemma because only 2 choices are provided; one is that high-dose laxatives have better bowel cleansing effects but poor tolerance, and the other is that low-dose laxatives are easy to tolerate but have poor bowel preparation. Therefore, it is unclear how to use this conclusion in clinical practice. If taking the adenoma detection rate into consideration, low-volume laxatives are associated with comparable adenoma detection rate and better tolerability, which may make them a better choice in clinical practice. Further research is necessary. Finally, from the patient demographics and clinical characteristics (Table 1), we find that the total number of female patients (1205) and the number (304 vs 951) and proportion (52.1% vs 54.4%) of women in each group were incorrect. We hope the authors could correct this minor error. The Bowel CLEANsing National Initiative: High-Volume Split-Dose Vs Low-Volume Split-Dose Polyethylene Glycol Preparations: A Randomized Controlled TrialClinical Gastroenterology and HepatologyVol. 20Issue 6PreviewThe aim of this study was to compare high-volume polyethylene glycol (PEG) with low-volume PEG with bisacodyl split-dosing regimens. Full-Text PDF ReplyClinical Gastroenterology and HepatologyVol. 20Issue 9PreviewWe thank Dr Kai and colleagues for their letter addressing selected aspects our recent work entitled “The Bowel CLEANsing National Initiative: High-Volume Split-Dose Vs Low-Volume Split-Dose Polyethylene Glycol Preparations: A Randomized Controlled Trial.”1 We address each of the issues in turn in the order raised by the readers. Full-Text PDF