Review for 10.1186/s12876-015-0354-7 (2015)

Reviewer ’s report  
 
Title: Trans -anal irrigation therapy to treat adult chronic functional constipation: A systematic  
review and meta -analysis  
 
Version: 0 Date: 01 Sep 2015  
 
Reviewer: Amanda Salis  
 
Reviewer's report:  
 
This is a well -written and well -conducted systematic review and meta -analysis that aims to  
determine whether or not trans -anal irrigation is useful for constipation. The results can 
potentially  inform on clinical practice as well as potentially helping to clarify the direction of 
future research  in this field.  
 
1. The Abstrac t should define what is meant by 'response rate'.  
 
2. In the Abstract, as  well as elsewhere in the paper, it will be useful to qualify whether or 
not an approximately 50%  'response rate' is good or not. On the one hand, this may be 
considered to be no better  than tossing  a coin, in that approximately half of the 
participants will report positive outcomes, and one half  will report no change. Given that 
there were no controlled studies available to review, how can the  authors know whether 
or not this was any be tter than a placebo effect?  
 
3. The Introduction would  benefit from more information about trans -anal irrigation, in a 
general sense. What is it? What are  the proposed mechanisms of action, how often is the 
procedure applied and over what time frame?  What ot her indications is it used for?  
 
4. The meaning of the triangular brackets on pages 4 and 5,  with odd dates, are not clear. 
Why were the data bases searched from such widely varying start and  end dates? This 
should be clarified.  
 
5. How would the Authors recomm end that future studies in  this field assess outcomes, 
based on the findings from this review and meta -analysis?  
 
6. On lines  194 to 196, specific examples of what the authors perceive to be 'minor and self -
limiting' side  effects should be given, as well as specific examples of what the authors 
perceive to be 'major  complications'. The same point applies to page 10, where 'mostly 
minor' side effects are again  mentioned.  
 
7. On page 11, it would be helpful if the authors provided some specific and explicit  
sente nces as to how they see the current review and meta -analy sis extending the findings 
from the other two systematic reviews on trans -anal irrigation, used for slightly different 
indications than  those assessed in the current study. Also, do the findings from  the current 
paper agree or disagree  with those previous findings?  
8. It is difficult to understand Figure 2 and the results from this metaanalysis,  because it is 
not clear whether 50% is a good number for a response rate, or not. It seems  to be not 
different from a placebo effect, which may also be expected to result in 50% of patients  
reporting a positive effect, due to random chance alone. More discussion as to what is a 
good  outcome is required, perhaps making use of literature that has used RCTs o f similar 
procedures.  
 
9. The paper will benefit from a strong clinical take -home message. Should patients with  
constipation of the types investigated in this review be recommended for trans -anal 
irrigation?  What is the cost -benefit ratio, in the author's op inion? Exactly what further 
research should be  done in this field now to address the identified gaps in knowledge?  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work in clude 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 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 as sess 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 i n the 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 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 o f 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 that I have no competing i nterests.  
 
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 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