Review for 10.1186/s12876-019-1006-0 (2019)

Reviewer ’s report  
 
Title: The role of endoscopic dilation and stents in refractory benign esophageal strictures: a 
retrospective analysis.  
 
Version: 1 Date: 25 Jan 2019  
 
Reviewer: Research Square  
 
Reviewer's report:  
 
"STATISTICAL REVIEWER ASSESSMENT:  
Is the study design appropriate for the research question (considering whether the analyzed 
population accurately r eflects the design and whether you see any problems with 
control/comparison groups, e.g., likely confounders)?  
No - there are major issues  
 
Are methodologies adequate and well implemented (considering whether assumptions are 
addressed and whether analyses are robust)?  
No - there are major issues  
 
Are the analyses adequately communicated (considering whether reporting details are adequate 
and whether figures and tables are well labeled and described)?  
No - there are minor issues  
 
Does the interpretation accu rately reflect the analyses without overstatement (considering 
whether limitations/bias are acknowledged and whether accurate descriptors, e.g., 'significant', 
are used?  
No - there are minor issues  
 
Could an appropriately REVISED version of this work repre sent a statistically sound 
contribution?  
Probably - with minor revisions  
STATISTICAL REVIEWER COMMENTS:  
This is a retrospective observational study of a small sample size drawn from a single medical 
center. It evaluated several outcomes and had set out to achieve several aims.  
The study seems methodologically sound given its observational nature, although there are a few 
major and other minor concerns I have from a statistical and methodological perspectives.  
 
REQUESTED REVISIONS:  
To start with, the study is of a very small sample size, leading to under powering, which is 
particularly problematic since t he authors had set out to achieve many aims and evaluate too 
many outcomes from this small low power study. I have detailed below a few specific points that 
need addressing. Before heading into that, I want to mention that the medical record review 
process  is vague and not detailed enough. Other than the time frame of patients included, how 
were the patients identified and their inclusion criteria, who carried out the review process, how 
were the data extracted, managed, and stored, who cleaned the data, we re there any data 
verification phase and who was it carried out by, ... etc. Some more detail is needed on this 
phase. Also, a brief description of the patient population served by this medical center would be 
great. Is it a local population, do patients t ravel to be cared for, is it a diverse population or 
homogeneous, ... etc.  
The authors used descriptive analyses and their methods were clear and well reported.  
For the logistic regression used, what are the factors that were included in these models? Wh at 
were the outcomes adjusted for? Please list them out clearly. (It is not clear neither from the text 
nor from the tables).  
Was there any attempt to do matching in the selection process, or any propensity score matching 
later at the analysis stage? Was there any testing done to evaluate the comparability of the two 
groups for the uni -variate analysis?  
In the paragraph of the Results addressing the  Dysphagia -free period, line 180: what was the 
magnitude of prediction? Only mentioning the p value is not enough to understand this 
relationship.  
The rest of the results in this section and previous section to it seem well done and well reported 
otherwise.  
Under clinical outcomes and adverse events, line 213: the CI is extremely wide! Please interpret 
this finding accordingly, as this analysis is very under -powered.  
The CI on line 217  of the same page and section is barely significant (approaching 1 closely). 
Also please interpret this finding accordingly.  
The rest of the findings seem well interpreted an d reported.  
 
ADDITIONAL REQUESTS/SUGGESTIONS:  
See comments above"  
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 sta tistical 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 t he 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 organisat ion 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 reimbursemen ts, 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 t his 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.  
 
This reviewer has been recruited by a partner organization, Research Square. Reviewers with 
declared or apparent competing interests are not utilized for these reviews. This reviewer has 
agreed to publication of their comments online under a Creative Commons Attribution License 
attributed to Research Square and was paid a small honorarium for completing the review within 
a specified timeframe. Honoraria for reviews such as this are paid regar dless of the reviewer 
recommendation.  
 
I agree to the open peer review policy o f the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. 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/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential  comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal