Review for 10.1186/s12876-018-0824-9 (2018)

Reviewer ’s report  
 
Title: Can coffee or chewing gum decrease transit times in Colon Capsule Endoscopy? A 
randomized controlled trial  
 
Version: 1 Date: 05 May 2018  
 
Reviewer: Carlo Maria Girelli  
 
Reviewer's report:  
 
 My major concern regards the choice of "per protocol analys is" which can introduce a selection 
bias, but on the other hand this methodological approach seems preferable in the screening 
setting, for ethical reasons (Giorgi -Rossi P, BMC Med Ethics. 2014 Mar 28; 15:28). I guess this 
clarification should be added in the Methods section.  
 
Minor issues:  
1. Introduction, line 62 -63 "low sensitivity of the iFOBT induces a substantial number of false 
positive…". A low sensitivity induces several false NEGATIVE, not false positive results.  
 
2. Figure 2. I don't understand the meaning of the "pellets" in the control column. Please, 
explain  
 
3. Reference # 18 is incomplete. Please, add "in press" with the doi indication if available.  
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 t he 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:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five ye ars 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 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 currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, fundi ng, 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 interest  
 
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  editors, which will not be published.  
 
I agree to the open peer review policy of the journal