Review for 10.1186/s12876-020-01267-2 (2020)

Reviewer ’s report  
 
Title: The relationship between metabolic syndrome and increased risk of Barrett's esophagus: 
An Updated systematic review and meta -analysis  
 
Version: 1 Date: 30 Oct 2019  
 
Reviewer: Shao -Hua Xie  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please o nly upload as attachments annotated versions of manuscripts, graphs, 
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This systematic revie w and meta -analysis summarized the epidemiological evidence regarding 
the association between metabolic syndrome and risk of Barrett's esophagus.  
1. The literature search strategy may not be the best because only MeSH terms were searched 
for. Some studies may not be well indexed by MeSH terms in these electronic databases. And the 
flowchart of selection of studies (Figure 1) is not easy to read with many crossing lines.  
2. It is unknown whether random -effect model or fixed -effect model was used in the meta -
analysis.  
3. A P value below 0.10 (instead of 0.05) in the Q test for heterogeneity is congenitally 
considered as significant.  
4. It is encouraged to interpret the results regarding the strength of association and confidence 
intervals, rather than P values . A weak association can be statistically significant in a sufficiently 
large sample.  
5. The authors conducted meta -regression on year of publication, but did not discuss the 
implications of such test.  
6. The authors assessed the study quality according to  NOS scores, which is believed to be 
somewhat subjective. It is recommended to display the characteristics of each study regarding 
the major sources of bias, e.g. response rate, completeness of follow -up, covariates 
controlled/adjusted for. And it is also recommended to present the quality scores for individual 
items.  
7. Abbreviations should be spelt out in first use, e.g. MetS in Abstract.  
8. Introduction: the description of meta -analysis methodology in last paragraph is not completely 
appropriate (meta -analysis refers to the statistical method pooling effect size estimates only and 
is not necessarily a subset of systematic review) and not needed.  
9. Readers may wish to know how well the potential confounders in the included studies were 
controlled for, and  this will affect the validity of the meta -analysis as well. Subgroup analysis 
may be needed by adjustment for the major risk factors of Barrett's esophagus, e.g. reflux.  
10. The authors may wish to elaborate a bit their discussion on limitations of the study. They 
mentioned that most studies were conducted in the United States, which might influence the 
results. In which way? It should be specified.  
11. The authors may dis cuss a bit the relevance of the findings, e.g. how would these be helpful 
for clinical or public health practice.   
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necess ary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
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 st atistics 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 statisti cs 
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the followi ng 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 st ocks 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 com peting 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.  
 
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