Review for 10.1186/s12876-022-02118-y (2022)

Reviewer’s report
Title: 
Overlap between irritable bowel syndrome and common gastrointestinal
diagnoses: a retrospective cohort study of 29,553 outpatients in Germany
Version: 
1 
Date: 
02 Dec 2021
Reviewer's report:
The manuscript by Loosen and colleagues is a retrospective study on the
diagnosis of irritable bowel syndrome (IBS) in a cohort of 29553 outpatients in
Germany.
The study is brief and conclusions are fairly bold and at the same time obvious
given that IBS is known to often have many comorbidities. While I agree that
there seem to be an overestimation of IBS cases in general, as was pointed out by
the last iteration of Rome criteria (IV) that lowered the global prevalence of IBS
in comparison to the previous Rome III (Oka, P. et al. 2020), there are substantial
issues in the current manuscript:
-The authors do not discuss the fact that is already known that IBS can develop
after infectious gastroenteritis, viral or bacterial, and this is known as post-
infectious IBS.
-The authors do not comment on the fact that most IBS patients present with
psychological comorbidities as well.
-It would be nice to have a Table of the characteristics of the patients included in
the analysis.
-What is the general prevalence of IBS in Germany, maybe the authors should
put the data into perspective for the reader.
-Most of the comorbidities shown by the authors are already known, what is the
novelty of the current study? Please highlight the novel findings.
-I am not sure I understood why developing other comorbidities after IBS
diagnosis would put into question the IBS diagnosis, unless the new diagnosis
include an organic disorder that explians IBS symptoms.
-How do these data on IBS patients compare to other diseased populations
(functional and organic)? 
-Please review carefully the manuscript for sentences construction and written
English.
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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?
No
Are the methods sufficiently described to allow the study to be repeated?
Yes
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Yes
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Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes