Review for 10.1186/s12876-025-03885-0 (2025)

Title: A randomized, controlled trial of oral sulfate solution versus polyethylene glycol for
bowel preparation for colonoscopy
Version: 1 Date: 18 Jan 2025
Reviewer's report:
This RCT aimed to conduct a head-to-head comparison between bowel preparation with OSS
and the standard PEG.
The findings are valuable as OSS is emerging as an alternative, and there is a general need to
identify low-volume preparations that are effective, safe, and have good palatability to reduce
rates of suboptimal bowel preparation in the general population. This is particularly critical in
colorectal cancer screening settings to improve the neoplasia detection rate.
Here are some suggestions and observations:
1) In the introduction, I recommend mentioning that there are also subpopulations who
require multiple bowel preparations and colonoscopies throughout their lives, such as
patients with IBD. For these patients, OSS has begun to show some preliminary evidence
of utility (this could be briefly discussed in one sentence using these references: https://
pubmed.ncbi.nlm.nih.gov/37034970/ and https://pubmed.ncbi.nlm.nih.gov/38130742/). It is
particularly important to consider the safety of these preparations for such populations, as current
guidelines only recommend PEG-based solutions for them.
2) In the inclusion criteria, it is stated that patients were included for their first-time screening
colonoscopy, yet it is also mentioned that indications included polyp surveillance, bleeding, and
changes in bowel habits. These indications do not align with screening, which, by definition,
applies to asymptomatic individuals based on age, comorbidities that increase colorectal cancer
risk, and family history. This point needs to be clarified.
3) The exclusion criteria should be rewritten. This is a randomised controlled trial, not an
observational study. Specific definitions are required for terms like "severe dysfunction of the
heart, liver, kidneys," and similar conditions. Were dehydrated patients included? What about
those with severe ongoing infections or decompensated severe comorbidities? The criteria need
to be reworked from scratch and written more professionally. Refer to the CONSORT checklist
as a guideline.
4) “Web-based random generator” is insufficiently detailed. Specify its name, where it can be
found, how it works, how you used it, and how randomisation was performed. Transparency
is crucial in trials.
5) In the colon-cleansing methods section, clarify that both bowel preparations were split-dose
regimens.
6) The sentence “Furthermore, the colonoscopy evaluation of intraluminal bubbles is also
assessed according to the following criteria” is written in the present tense, but the study has
already been conducted. It should be in the past tense. Please be careful with this kind of mistake
throughout the manuscript—it is not a protocol.
7) In the methods section, specify how adverse events were classified. Did you use the WHO
classification? Provide details.
8) What technique was employed by the endoscopists during colonoscopy? Was the use of
techniques such as water-immersion or water-exchange permitted? If so, specify the utilisation
rate in both groups and conduct a significance test to evaluate potential differences, as this
represents a source of bias.