Review for 10.1186/s12876-019-0945-9 (2019)

Reviewer ’s report  
 
Title: Association between digestive symptoms and sleep disturbance: a cross -sectional  
community -based study  
 
Version: 1 Date: 02 Oct 2018  
 
Reviewer: Reviewer 2  
 
Reviewer's report:  
 
PEER REVIEWER COMMENTS: To view the full report from the academic peer reviewer, 
please see the attached file.  
 
REVIEWER COMMENTS FROM REPORT: This is a cross -sectional descriptive study of the 
associations between symptoms of sleep and digestive dysfunction. The work is generally well 
written (though it will benefit from a thorough proofreading) and concisely described. Both sleep 
and di gestive health are important issues that affect a large proportion of the population, and the 
relations between them have been relatively under -addressed, so the paper addresses a significant 
issue. The authors have used well -validated subjective instrumen ts for symptom self -report in a 
relatively large study sample. The conclusions are based on the findings and may be valuable for 
implementing improved standard of care among practicing physicians, even if causal deductions 
cannot be drawn. Nevertheless, th ere is room for improvement, and I offer several non -trivial 
suggestions toward further strengthening this interesting report.  
 
REQUESTED REVISIONS:  
Introduction: This section is relatively unfocused for the first page or so. The general information 
abou t sleep disorders prevalence is confusing insofar as specific sleep disorders were not 
measured in this study. A single sentence regarding the global epidemiology of generally 
inadequate/disordered sleep would suffice, allowing the main focus to rest on th e relationships 
between sleep and GI symptoms.  
Methods:  
Few details are provided regarding the larger study. Basic information is needed, such as 
recruitment methods and context (were these all patients at a GI and/or sleep clinic, or from the 
general pop ulation?), response rates, methods of survey administration, etc.  
It is unclear whether the PSQI or GSRS were completed in their original English versions or 
translated (and if so, whether this was done appropriately) into Korean.  
It is unclear why the PSQ I cutoff of 5 was used (a reference is provided, but a rationale should be 
provided).  
The National Sleep Foundation (which has a strong conflict of interest with commercial markets 
and does not use sound data collection methods) recommendations are a poor choice for 
categorizing sufficient/insufficient sleep.  
No psychometrics are provided for the GSRS.  
The statement "Continuous variables were categorized as appropriate categorical variables based 
on their distributions." is unclear; a cutoff is provided for  the global PSQI and sleep duration by 
age, but for none of the other measures.  
It is unclear why the covariates were chosen (e.g., IV's differing on univariate analyses).  
Results: Inclusion of effect size information for all statistically significant find ings (i.e., in the 
tables) would help strengthen the report considerably.  
Discussion: The authors generally summarize the previous literature and then state that none of it 
is comparable to their own findings. This may be strictly true, but some aspects (e .g., age 
findings, sex differences) can and should be discussed in the context of what is currently known 
on the topics.  
 
Are the methods appropriate and well described?  
If no t, 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.  
 
No 
 
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 recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
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 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 al l of the above, write 'I declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
This reviewer has been recruited by a partner  organization, Research Square. Reviewers with 
declared or apparent competing interests are not utilized for these reviews. This reviewer has 
agreed to publication of their comments online under a Creative Commons Attribution License 
attributed to Research  Square and was paid a small honorarium for completing the review within 
a specified timeframe. Honoraria for reviews such as this are paid regardless of the reviewer 
recommendation.  
 
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