Review for 10.1186/s12876-019-0994-0 (2019)

Reviewer ’s report  
 
Title: Defining constipation to estimate its prevalence in the community: results from a national 
survey  
 
Version: 1 Date: 14 Jan 2019  
 
Reviewer: Klaus Bielefeldt  
 
Reviewer's report:  
 
This is a  revised manuscript describing the prevalence of constipation based on survey results.  
The response rate seems to be good and apparently reflects the makeup of the Australian 
population.  While there are some weaknesses, the results are potentially releva nt and interesting.   
My main conceptual concern relates to the study design and their impact on results.  The authors 
use the Rome III criteria for constipation as their 'gold standard', which is then compared to 
simple definitions relying on a single cri terion.   Independent of the results presented in this 
paper, I would expect that a more complex and more stringent definition of specific conditions 
comes with a 'higher' bar.  Therefore, it is not surprising that responses addressing stool 
frequency or a  global sense of constipation (without required chronicity) lead to different results.   
Conceptually, I am also struggling with the use of the terms positive predictive value, sensitivity 
etc., if the questions address different issues.  Asking about prob lems with constipation within 
the last 12 months (no stipulation related to chronicity) looks for a somewhat different problem 
than the Rome criteria, which require more consistent abnormalities in a shorter time frame.  
One key message (not truly highlight ed in the manuscript) is the role of perceived problems with 
stool passage and incomplete emptying in this cohort.  
Table 2 does not make sense with the number of responders for the shorter time period (3 
months) being twice that for the entire year (should  at least be the same).  
 
MINOR:  
Page 9, line 12: 2024 participants are obviously more than 7.2% of the sample contacted.  
If 13% discussed constipation with providers (perhaps the more relevant group), what makes 
them unique?  
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 co ntrols?  
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.  
 
No 
 
Are you able to asses s 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 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 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 recei ved 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?  
 
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below.  If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
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