Review for 10.1186/s12876-018-0927-3 (2019)

Reviewer ’s report  
 
Title: Helicobacter pylori infections in Ethiopia;  prevalence and associated factors: A systematic 
review and meta -analysis  
 
Version: 0 Date: 14 Nov 2018  
 
Reviewer: Jen-Hao Yeh  
 
Reviewer's report:  
 
This is a systematic review and meta -analysis to infection rates of Helicobacter pylori among 
different areas and populations in Ethopia. In this article, the authors found several risk factors, 
such as alcohol consumption, absence of hand washing, and  presence of GI symptoms were 
associated with higher infection rate.  
 
Although this is a comprehensive review, several points need to be addressed.  
1. The authors provided the search strategy and keywords. Using this strategy on Google 
Scholar, there is 436 records; and this seems not consistent with the PRISMA flow chart in 
Figure 1. In addition, I can not find some unpublished articles in the refere nce (such as 
Alemayahu, 2011). I would like the authors provide the sources, and may consider if these 
unpublished studies should be present in this meta -analysis.  
 
2. In the results of risk factors of H.P infection, the authors stated: "Even though not 
significant; male participants (OR =…) and urban residents (OR = …) were more likely to 
be infected …". In my opinion, this was not an appropriate statement because both results 
were statistically significant, and the pool OR can favor either side merely by c hance. A 
more conservative and solid inference is recommended.  
 
3. In table 1., Serology test is apparently associated with higher infection rate compared to 
stool antigen test. Since stool antigen is a relative new method, it is possible the trend of 
declined infection rate by time is confounded by the test method. I suggest the authors can 
analyze the effect in the stool antigen group additionally (e.g: infection rate among 2008 -
2013 vs. later).  
 
4. The authors stated "participants with gastrointestinal (G I) symptoms were 2.2 times more 
likely to be infected with H.pylori …". It might be true with risk ratio, but this is not the case 
for odds ratio.  
 
5. This review included a large number of studies, therefore more delicate and representative 
analysis may be  carried out. For example, 10 studies were noted to have multiple tests for 
validation of infection; how about the pooled results of these studies ?  
 
Minor points:  
1. The search process should be done with independent reviewers to minimize bias and missin g 
data.  
 
2. The form of tables might revise to fit for formal publication form (Only bottom frame lines 
should be present).  
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 necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Unable to assess  
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
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:  
 
Needs some language corrections before being published  
 
  
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 publi cation 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 curr ently 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  
 
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