Review for 10.1186/s12876-021-02037-4 (2021)

Reviewer’s report
Title: 
Validation and modification of existing mortality prediction model for
lower gastrointestinal bleeding: A retrospective study
Version: 
1 
Date: 
12 Sep 2021
Reviewer's report:
Thank you for giving me an opportunity to review this manuscript.
Indeed, it is an interesting study. Here, I have identified several things that the
authors can improve:
- for abstract (line 33), the author should also include co-morbidities and
medications (based on selection of variables stated -line 87) 
-Line 40: What is CNUH? Should be introduced in methods 
- Methods (Line 87): The author wrote predictor candidates, which is supposedly
predictor variables 
- The purpose of using ASA score should be introduced under methods rather
than in the discussion. 
- Line 107: median (interquartile range). The sentences seems incomplete when
suddenly ended with normality. 
-Line 108: To state what is the univariate test, method to select and eliminate the
variables. sample size. Consider to report these: Multicollinearity and interaction,
Hosmer-Lemeshow Test, classification table prior to AUROC
-Line 113: I dont understand the reason the author limited their variables to 4
and 5 only. 
-Line 145: Findings of receiving LGIB treatment n died should be at early report
of findings as the author were looking for the factors associated to this. 
-Results: The authors do not have to explain all the results of the descriptive
findings in the table. 
-Line 252: AIMS65 n ABC shold be introduced early under introduction as the
authors aimed to compare with these
-Line 260: Is this finding from this study or literature review? This study only
described measuring the AUROC of CNUH
I still can't understand how the CNUH 4 and 5 is proposed as a scoring system.
Conclusion: to highlight what is new compare to the existing model. The authors
stated that they had developed " a model for predicting the risk of LGIB-related
mortality". It should be consistent with the objective to propose a scoring
system.
All the best to you. Thank you.
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 after the final decision on the manuscript has been made. 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?
No
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes