Review for 10.1186/s12876-020-01593-5 (2021)

Reviewer’s report
Title: 
The Level and Prevalence of Depression and Anxiety among Patients with
Different Subtypes of Irritable Bowel Syndrome: A Network Meta-analysis
Version: 
0 
Date: 
02 Jun 2020
Reviewer's report:
This is a meta-analysis of 11 studies with 4400 participants showing no
significant difference in the level of depression and anxiety among different
irritable bowel syndrome (IBS)-subtype patients.
Comments
There are serious limitations in this study such as: 1. difference in the definition
of IBS subtypes according to past Rome criteria (Rome III criteria were used in 4
studies, Rome II criteria in 6, one study just mentioned they used Rome criteria,
and no study has been published based on the current Rome IV criteria); 2.
depression and anxiety criteria were not uniform among the studies and different
measurement scales were used; 3. comorbidities and other factors that might
have contributed to depression and anxiety were not assessed (low quality
papers); and 4. matched healthy control groups were not employed by all studies.
The authors acknowledged that due to the high heterogeneity and small number
of studies, they did not conduct a meta-analysis. In a recent relative meta-
analysis published in 2019 (Zamani M, et al. Aliment Pharmacol Ther.
2019;50:132
‐
143), subgroup analyses from 5 studies showed that the pooled
prevalence rates of anxiety symptoms were 43.7% (95% CI: 33.2
‐
54.2), 35.5%
(95% CI: 26.9
‐
44.1) and 37% (95% CI: 26.9
‐
47) in patients with IBS
‐
C, IBS
‐
D
and IBS
‐
M respectively, i.e., quite similar in all subgroups, as in the present
study. However, Zamani et al. also reported a very high heterogeneity among the
studies (I2 = 93.6%). In view of the above-mentioned comments, I am afraid that
the present study is neither novel not reliable to draw definitive conclusions.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
No
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the
authors.
No
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
No
Are you able to assess any statistics in the manuscript or would you
recommend an additional statistical review?
If an additional statistical review is recommended, please specify what aspects
require further assessment in your comments to the editors.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
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. 
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paper?
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interests' below. If your reply is yes to any, please give details below.
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