Review for 10.1186/s12876-019-1065-2 (2019)

Reviewer ’s report  
 
Title: Water exchange colonoscopy decreased adenoma miss rates compared with literature data 
and local data with CO2 insufflation: an observational study  
 
Version: 0 Date: 02 Jun 2019  
Reviewer: Rapat Pittayanon  
Reviewer's report:  
Dear the Editor and authors,  
 
I have reviewed the manuscript  entitled "Water exchange colonoscopy decreased adenoma miss 
rates compared with literature data and local data with CO2 insufflation: an observational study" 
with interest. This study evaluated the benefit of water exchange colonoscopy in colorectal 
cance r screening and surveillance in AMRs. However, there are many concerns as the following 
items;  
 
Major concerns  
1. This study aimed to report two studies; the first one compared the result to the data in 
previous literature whereas the second on compared th e data with the first one. 
Importantly, the study population in the second one overlapped to the population in 
previous literature. Why the authors do not compare the data from their two studies and 
focusing on those to eliminate the confusion of many sent ences in manuscript? Please re -
consider.  
 
2. We usually show every number in result part. Please add the number from the previous 
literature in this sentence; "WE showed considerably lower AMRs in the right (17.5%) 
and proximal (15.5%) colon than those in the literature"  
 
3. The figure 1 and 2 do not make any sense. The eligible patients should be informed for 
two-time (tandem) colonoscopy in the same session because this procedure is not a 
standard practice. Thus, the eligible patients do not mean all patie nts who underwent 
colonoscopy in that period. Otherwise, the reason for single colonoscopy or non -WE 
colonoscopy should be explained.  
 
4. The first two sentences in the second paragraph of discussion part was similar to the 
content of introduction. Please modify.  
 
5. Please give the hypothesis to support the findings in this study; how the "water exchange" 
provided lower AMRs at right sided/proximal colon compared to" CO2 insufflation"?  
 
 
Minor concerns  
1. At the beginning of each sentence, it should be st arted with alphabet, not number, for 
example "58% of postcolonoscopy CRCs (PCCRCs) were attributed………….." in the 
introduction part. Please revise.  
 
2. There is a typo; "fist -pass" on page 7.  
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.  
 
Unable to assess  
 
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 r ecommended, 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  
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 financia lly from the publication 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 o r 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 yo u 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 . 
 
I agree to the open peer review policy of 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 unde r 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