Review for 10.1186/s12876-018-0800-4 (2018)

Reviewer ’s report  
Title: Variable Endoscopist Performance in Proximal and Distal Adenoma Detection during 
Colonoscopy: A Retrospective Cohort Study  
 
Version: 1 Date: 06 Jan 2018  
 
Reviewer: Marc J. Zuckerman  
 
Reviewer's report:  
Please include all comments for the authors in this  box rather than uploading your report as an 
attachment. Please only upload as attachments annotated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Interesting paper looking at the relationship between novel quality indicators of proximal ADR 
and distal ADR as opposed to standard ADR in a retrospective cohort study using a database of 
screening colonoscopies from 2009 - 2011.  
Good discussion, including limitations and conclusi on. Adequate references.  
 
Minor points:  
 
Abstract - Under methods, consider stating screening colonoscopy instead of just colonoscopy, 
so it is clear rather than implied from the subsequent comment that it is in a colon cancer 
screening center  
The conclusi on may be overstated.  It might be better to say, more accurate feedback on 
endoscopic performance than the most accurate, since other novel indicators were not included in 
the comparison.  
 
Methods - Study Protocol: why is the data from 2009 - 2011 and not  more recent, or is this the 
database available?  
 
Methods - Study Protocol:  inclusion criteria is stated as age 50 to 75.  Why does the flow sheet 
list ages 46 to 74?  
 
Since withdrawal times were not available. it might be a good idea to comment in method s about 
withdrawal times not being recorded or some other reference to standard practice.  
The comment in the discussion that, at our center colonoscopy procedures are scheduled into 30 -
minute time slots, could be moved to methods  
 
Results - The numbers fro m results do not appear to match those in the flow chart. e.g. 1907 
underwent screening colonoscopies  
 
Adenoma detection - can you comment on the overall adenoma to polyp detection rate quotient 
compared with other studies, is this 50% low?  
 
Discussion - the comment that, at our center colonoscopy procedures are scheduled into 30 -
minute time slots, could be moved to methods.  
 
Is the comment that adenoma detection also showed a weak inverse association with endoscopy 
years of practice reported in the results ?  There are statements about significant associations of 
years of practice and ADR.  
 
Flow chart - Reconcile apparent inconsistencies between flow chart and methods/results 
numbers.  
 
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.  
Yes 
 
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 manus cript or would you recommend an 
additional statistical revi ew? 
If an additional statistical review is recommended, please speci fy what aspects require further 
assessment in your comments to the editors.  
I recommend additional statistical review  
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  
organisati on 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 manuscrip t, 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 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 I have no competing interests.  
 
I agree to the open peer review policy of the journal. I u nderstand 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 repor t 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 e ditors, which will not be published.  
 
I agree to the open peer review policy of the journal