Review for 10.1186/s12876-025-03707-3 (2025)

Title: Comparing the bowel cleansing efficacy between sodium picosulfate vs. 2L polyethylene
glycol electrolyte lavage solution for colonoscopy: A prospective observational study
Version: 3 Date: 04 Jan 2025
Reviewer's report:
Abstract
"they used" probably should be "they chose".
"Both groups achieved an adequate bowel cleansing rate exceeding 90% (92.2% vs. 91.3%,
P=0.437), with comparable polyp detection rates (42.2% vs. 45.5%, P=0.096) and high
willingness to repeat the procedure (99.2% vs. 99%, P=0.588). "
There were no statistically significant differences between the PICA and PEG-ELS groups in
cleansing the bowel adequately (92.2% vs. 91.3%, P=0.437), polyp detection rates (42.2% vs.
45.5%, P=0.096) and willingness to repeat the procedure with the same preparation  (99.2% vs.
99%, P=0.588).
"There were significant differences in the BBPS score of the total and the right colon between
the two groups, and PICO group was significantly higher than 2L PEG-ELS group [(6.90 ±
1.19) vs. (6.81 ± 1.14), P=0.016 ; (2.15 ± 0.53) vs. (2.11 ± 0.51), P=0.005]. " - too complex,
you need to give the data after each statement, not at the end. Say which group was statistically
significantly better.
"In this prospective observational study, both PICO and 2L PEG-ELS regimens achieved bowel
cleansing rate of more than 90% and comparable polyp detection rates. " This is just a repeat
of what you said above.
"Despite differing adverse reaction profiles more nausea in the 2L PEG-ELS group and more
sleep disturbances in the PICO group nearly all patients expressed willingness to repeat the same
regimen. " this is new data and can not just show up in the conclusion.
Your conclusion is probably "both PICO and 2L PEG-ELS are safe and effective options for
bowel cleansing in the Chinese population."
Intro
"Colonoscopy " Screening colonoscopy
"a a low-volume " remove an "a"
Much better - still could be shorter. You can leave it if you choose.
Methods
"The primary outcome was the rate of adequate bowel cleansing between the two groups. " as
defined by ?????
"Each section is scored on a scale of 0 to 3 based on cleanliness. " after cleaning maneuvers
were completed.
"The bowel air bubble score was categorized into four levels according to its impact on mucosal
visibility" - was simethicone used in the washing fluid if needed?
Your description of the patient questionnaire needs to be briefer and more specific, for example:
The patient questionnaire asked  age, height, weight;  Did you take the dimethyl silicone oil
(Yes or No); what did you eat the day before the procedure? Did you difficulty falling asleep  or
sleep disruption from have a B ? (Yes or No)  Would you choose the same bowel preparation
regimen again? (yes or No). etc.
RESULTS
TABLE 1
"Low-residue diet before procedure (n, %)  59 (8.0)   463 (9.9)  0.103" what does this mean?
Do you mean noncompliance with low residual diet?
"There were statistically significant differences between the two groups in the BBPS score of
the total and the right colon, the PICO group was significantly higher than the 2L PEG-ELS
group [(6.90 ± 1.19) vs. (6.81 ± 1.14), P=0.016 ; (2.15 ± 0.53) vs. (2.11 ± 0.51), P=0.005]. " --
too complex. Give the data after each statement.
Table 2
Adequate bowel cleansing rate (n, %) should be all segments 2 or 3 (or >=2).
"Bowel preparation completion rate (n, %)
25-50%  0 (0)   3 (0.1)
50-75%  1 (0.1)   22 (0.5)
75-100%  738 (99.9)   4659 (99.5)
" - what was the question they were asked? Do you have actual numbers (63% or 99%) or did
they have 4 choices (0-25,26-50, etc.)? If you have the data, mean +- SD should be included.
"as shown in Table 3" - needs to start the paragraph.
Table 3 -nice
Discussion
"The results demonstrated that both PICO and 2L PEG-ELS achieved an adequate bowel
cleansing rate of 92.2% and 91.3%. " - you MUST use statistically significant in the sentence
describing your primary endpoint.
This prospective observational study found no statistically significant differences in the number
of colons cleansed adequately as measured by the Boston BPS  between the PICO and 2L PEG-
ELS groups (data here, p=).
Next paragraph describe the secondary endpoints of cleanliness (Total BPS and segments BPS
scores) and qaulity. Most studies use Total BPS as the primary endpoint because it is a more
sensitive measure of cleanliness. Adequate/inadequate (a binary variable) is a much more crude
measure and it will take a much bigger study to show statistically significant differences. You
can comment that the PICO did appear to be somewhat more effective as measured by these
endpoints, but the differences were small, but statistically significant.
Next compare you data on cleanliness to other studies as briefly as you can comparing the
outcome data.
Next talk about the secondary endpoint of tolerance between the 2 groups and compare your
data to that from other studies.
Get rid of most of the discussion on risk factors for poor preps. This is not a focus of your study
and your discussion is too long and unfocused. You can discuss it all in one short paragraph.
"In terms of adverse effects, patients in the PICO group experienced less nausea compared to
those in the 2L PEG-ELS group. The low incidence of vomiting in the PICO group, which was
not statistically significant, may be attributed to the fact that the 2L PEG-ELS regimen is a low-
volume regimen with fewer vomiting episodes, consistent with previous studies (30, 31)." if it
is not statistically significant, you can not discuss it as a difference. It is the same.
Your study DOES show statistically significantly less nausea and sleep disturbance.
You can briefly give a range of adequate cleansing rates from USA/Europe which are typically
in the low 80s with split dose 2 L PEG-ELS + Bisocodyl. Maybe comment on why this regimen
does better in China.
"Thus, in this study we compared the bowel cleansing efficacy between these two regimens, and
found a similar acceptable bowel cleaning efficacy, which added to our understanding of the
efficacy of 2L PEG-ELS and PICO in Chinese patients." too repetitive.
Shorten the paragraph on risks factors for inadequate bowel preparation and breigly state your
findings.
"In this prospective observational study, we found the proportion of low-risk populations in the
PICO and 2L PEG-ELS groups was 46% and 45%, respectively, and it’s comparable" - not
statistically significantly different.
Why did PICO group have less nausea? The volume was almost identical (2000 vs 2250). Time
to first dedication was faster in the PEG-ELS group and maybe that is why they had more
side effects. Because it went through the PICO group slower, they may have had more sleep
disturbances. This is a trade-off that your patients will need to take into account.
How might you improve your bowel cleaning rates above the low 90% range? Is this as good
as it will get in China?