Review for 10.1186/s12876-020-01597-1 (2021)

Reviewer’s report
Title: 
Prevalence and risk factors of bowel symptoms in Korean patients with
ulcerative colitis in endoscopic remission: a retrospective study
Version: 
0 
Date: 
22 Sep 2020
Reviewer's report:
Thank you for submitting this retrospective study on bowel symptoms in Korean
patients with endoscopically quiescent Ulcerative Colitis. The paper is overall
well written, the analsysis is well designed and rigorously conducted for
answering the reseach question, the conclusions are coherent, and the
limitantions cealry outlined. 
I have a few comments/concerns:
- It would be helpful to clarify when the maximum extent of UC was assessed; I
am assuming it was at a previous colonoscopy, but that is not immediately
evident reading the paper
- What would be the proposed explanation for rectal bleeding in patients who are
in remission? Since it is unclear what the reason was for the visit where the
symptoms were assessed (routine visit? patient presenting with worsening
symptoms?), especially since the range of the time interval between endoscopy
and evaluation is not reported (only the median is given), would it be a
reasonable concern to think that those patients were actually presenting with a
flare?
- What is your treatment algorithm for those patients considered in remission but
still experiencing symptoms? Fecal calprotectin was not measured to rule out
active disease. Was a new endoscopy perfromed, especially in those reporting
significant bleeding?
- The authors report "exposure" to certain medications. Does that refer to
historical treatments or the current regimen patients were receiving at the time of
evaluation? It would be helpful to know what the medical management was at
the time of assessment. Also, were any changes made in the treatment of patients
with persistent symptoms? Were serum levels of biologic drugs tested?
- Also, what's the clinical implication of these findings and how would this study
change practice, if in any way?
Thank you very much.
Publons Reviewer Recognition
. Springer Nature can send verification of this
review directly to Publons (a subsidiary of Clarivate Analytics). If you would
like to take advantage of this service, please click on the “Yes” option below.
Your name, email address, title of the reviewed manuscript, name of the journal,
and date of your review submission (the “Review Data”) will then be transmitted
to Publons upon publication of the manuscript. If you have already registered at
Publons, they will notify you of the receipt of this review and update your profile
as per your settings and their policy. If you are not registered with Publons, you
will receive an email from them asking you to register in order for them to be
able to recognize your review on your new profile page. Publons may use the
Review Data to generate derivative metadata for the benefit of Publons and you
as a reviewer, carefully considering the sensitivity of such information. For
example, Publons may verify your record as a reviewer by updating your profile
published on its webservice if you have registered for such service or help
editors to identify candidate reviewers. Please find the details of processing in
Publons’ privacy policy 
https://publons.com/about/terms
Yes
Declaration of competing interests
Please complete a declaration of competing interests, considering the following
questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
I declare that I have no competing interests
Reviewer Publication Consent.
 I agree for my report to be made available
under an Open Access Creative Commons CC-BY License (
http://creativecommons.org/licenses/by/4.0
) if this manuscript is accepted for
publication. Any comments that I do not wish to be included in the published
report have been included as confidential comments to the editor, which will not
be published.
If you are not happy for us to publish this report, please contact the editorial
office before completing the review.
If you wish, you can include your name in your published report. Please note
you must decide whether to include your name at the start of the process and
confirm this decision whenever prompted. If you change your decision later, we
will not be able to publish your name.
I agree to the terms of the CC-BY 4.0 license; please 
do not
 publish my name
with my report. (default)
Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
Yes
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes