Reviewer ’s report 
 
Title: Clinical outcomes of iatrogenic upper gastrointestinal en doscopic perforation: A 10 -year 
study  
 
Version: 0 Date: 03 Jul 2019  
 
Reviewer: Leonardo Eusebi  
 
Reviewer's report:  
 
I read with interest the article by Dae Hwan Kang et al. The study is a retrospective evaluation of 
the outcomes of patients wi th endoscopic perforation over a 10 -year period in a single 
endoscopic centre in Korea.  
 
The study includes a very large number of procedures and is well written. The topic and the 
results are not a great novelty.  
 
 
However, a few issues need to clarified:  
 
- First of all, the total number of procedures is not clear: the Authors report in the text 
several times that the total number of included endoscopies is 151.500. However, adding 
together all the different types of procedures (diagnostic endoscopy, ESD, E MR, ERP, 
etc.) the total number is 149.792, as it can be calculated both from the text in the 
Materials and Methods section and in Figure 1.  
 
The Authors need to clarify the correct numbers of the procedures and modify the statistics of the 
study according ly. 
 
- One of the aims of the study is to evaluate factors associated with mortality, however 
with only 3 cases of death out of 150.000 procedures, this evaluation cannot be 
performed or be in any way conclusive.  
 
- Though the Authors acknowledge in the lim itation of the study that over the scope clips 
cannot be used in Korea, this is a big limitation to the study as these types of clips have 
become the standard of practice in the endoscopic management of perforations in most 
countries, reducing post -perfora tion complications. This should be stressed out in the 
discussion.  
 
- There is no information about the use of CO2 during the procedures. Was it used during 
all procedures? Outcomes and complications of perforations differ largely depending on 
whether CO2 o r air is used during the endoscopic procedure.  
 
- Please remove "Usually" for the first sentence of the abstract and introduction.  
 
Are the metho ds 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.  
 
Yes 
 
Are the co nclusions 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 manus cript or would you recommend an 
additional statistical review?  
If an additional statistica l review is recommended, please speci fy 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  
Please complete a declaration of competing interests, considering the following questions:  
 
1.  Have you in the past five years received reimbursements, f ees, funding, or salary 
from an organisation that may in any way gain or lose financial ly from the 
publication of this manuscript, either now or in the future?  
 
2.  Do you hold any stocks or shares in an organisation t hat 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 f or 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 have no competing interests  
 
I agree to the open peer review policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted f or 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 in cluded as confidential comments 
to the editor s, which will not be published.  
 
I agree to the open peer review policy of the journal  
Reviewer ’s report 
 
Title: Clinical outcomes of iatrogenic upper gastrointestinal en doscopic perforation: A 10 -year 
study  
 
Version: 0 Date: 03 Jul 2019  
 
Reviewer: Leonardo Eusebi  
 
Reviewer's report:  
 
I read with interest the article by Dae Hwan Kang et al. The study is a retrospective evaluation of 
the outcomes of patients wi th endoscopic perforation over a 10 -year period in a single 
endoscopic centre in Korea.  
 
The study includes a very large number of procedures and is well written. The topic and the 
results are not a great novelty.  
 
 
However, a few issues need to clarified:  
 
- First of all, the total number of procedures is not clear: the Authors report in the text 
several times that the total number of included endoscopies is 151.500. However, adding 
together all the different types of procedures (diagnostic endoscopy, ESD, E MR, ERP, 
etc.) the total number is 149.792, as it can be calculated both from the text in the 
Materials and Methods section and in Figure 1.  
 
The Authors need to clarify the correct numbers of the procedures and modify the statistics of the 
study according ly. 
 
- One of the aims of the study is to evaluate factors associated with mortality, however 
with only 3 cases of death out of 150.000 procedures, this evaluation cannot be 
performed or be in any way conclusive.  
 
- Though the Authors acknowledge in the lim itation of the study that over the scope clips 
cannot be used in Korea, this is a big limitation to the study as these types of clips have 
become the standard of practice in the endoscopic management of perforations in most 
countries, reducing post -perfora tion complications. This should be stressed out in the 
discussion.  
 
- There is no information about the use of CO2 during the procedures. Was it used during 
all procedures? Outcomes and complications of perforations differ largely depending on 
whether CO2 o r air is used during the endoscopic procedure.  
 
- Please remove "Usually" for the first sentence of the abstract and introduction.  
 
Are the metho ds 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.  
 
Yes 
 
Are the co nclusions 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 manus cript or would you recommend an 
additional statistical review?  
If an additional statistica l review is recommended, please speci fy 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  
Please complete a declaration of competing interests, considering the following questions:  
 
1.  Have you in the past five years received reimbursements, f ees, funding, or salary 
from an organisation that may in any way gain or lose financial ly from the 
publication of this manuscript, either now or in the future?  
 
2.  Do you hold any stocks or shares in an organisation t hat 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 f or 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 have no competing interests  
 
I agree to the open peer review policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted f or 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 in cluded as confidential comments 
to the editor s, which will not be published.  
 
I agree to the open peer review policy of the journal  
Please review this paper.
user
Reviewer ’s report 
 
Title: Clinical outcomes of iatrogenic upper gastrointestinal en doscopic perforation: A 10 -year 
study  
 
Version: 0 Date: 03 Jul 2019  
 
Reviewer: Leonardo Eusebi  
 
Reviewer's report:  
 
I read with interest the article by Dae Hwan Kang et al. The study is a retrospective evaluation of 
the outcomes of patients wi th endoscopic perforation over a 10 -year period in a single 
endoscopic centre in Korea.  
 
The study includes a very large number of procedures and is well written. The topic and the 
results are not a great novelty.  
 
 
However, a few issues need to clarified:  
 
- First of all, the total number of procedures is not clear: the Authors report in the text 
several times that the total number of included endoscopies is 151.500. However, adding 
together all the different types of procedures (diagnostic endoscopy, ESD, E MR, ERP, 
etc.) the total number is 149.792, as it can be calculated both from the text in the 
Materials and Methods section and in Figure 1.  
 
The Authors need to clarify the correct numbers of the procedures and modify the statistics of the 
study according ly. 
 
- One of the aims of the study is to evaluate factors associated with mortality, however 
with only 3 cases of death out of 150.000 procedures, this evaluation cannot be 
performed or be in any way conclusive.  
 
- Though the Authors acknowledge in the lim itation of the study that over the scope clips 
cannot be used in Korea, this is a big limitation to the study as these types of clips have 
become the standard of practice in the endoscopic management of perforations in most 
countries, reducing post -perfora tion complications. This should be stressed out in the 
discussion.  
 
- There is no information about the use of CO2 during the procedures. Was it used during 
all procedures? Outcomes and complications of perforations differ largely depending on 
whether CO2 o r air is used during the endoscopic procedure.  
 
- Please remove "Usually" for the first sentence of the abstract and introduction.  
 
Are the metho ds 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.  
 
Yes 
 
Are the co nclusions 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 manus cript or would you recommend an 
additional statistical review?  
If an additional statistica l review is recommended, please speci fy 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  
Please complete a declaration of competing interests, considering the following questions:  
 
1.  Have you in the past five years received reimbursements, f ees, funding, or salary 
from an organisation that may in any way gain or lose financial ly from the 
publication of this manuscript, either now or in the future?  
 
2.  Do you hold any stocks or shares in an organisation t hat 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 f or 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 have no competing interests  
 
I agree to the open peer review policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted f or 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 in cluded as confidential comments 
to the editor s, which will not be published.  
 
I agree to the open peer review policy of the journal  
assistant