Review for 10.1186/s12876-019-0960-x (2019)

Reviewer ’s report  
 
Title:  The Role of Small Intestinal Bacterial Overgrowth (SIBO) in Non -alcoholic Fatty Liver 
Disease (NAFLD) Patients evaluated using Controlled Attenuation Parameter (CAP) Transient 
Elastography (TE): A Tertiary Referral Center Experience  
 
Version: 0 Date: 28 Dec 2018 
 
Reviewer:  Benjamin  Misselwitz  
 
Reviewer’s report:  
 
The authors stud y assess obesity, fatty liver disease and SIBO in a cohort of 160 patients. While 
most of the associations tested were negative, central obesity was associated with SIBO and the 
frequency of some bacteria strains were associated with NAFLD and fibrosis. I have some 
suggestions.  
 
 
Major points:  
 
- This is a largely negative study. The conclusions in the last sentence of the abstract ("NAFLD 
is a complex disease" and "SIBO plays an important role in patients with obesity") are not 
supported by the date. Simila rly, the last two sentences of the conclusion of the discussion are 
not supported by the data  
 
- Nutrition was not assessed (which would impact on microbiota and intestinal transit), data 
regarding smoking and alcohol consumption are also lacking.  
 
- The st udy argues against the utility of the "SIBO" breath test (the association of obesity and 
SIBO is not clinically useful since obesity is immediately obvious). However, studying the 
microbiota seems to hold some promise. This seems to    
 
- Multivariate analy sis should be strongly considered. Controlling for age, gender might unmask 
some associations.  
 
- Some tables should be fused if the same outcome is assessed. For all outcomes, the associations 
with all risk factors should be calculated. For instance, it i s unclear why we do not see the 
association of epidemiological risk factors and fibrosis degree. It seems, only a selection of the 
data is presented.  
 
- This is likely not the first paper studying the association of SIBO, obesity, central obesity, 
NAFLD, F ibrosis and the respective metabolic risk factors. However, the  discussion does not 
attempt to put the data in perspective to the current literature (i.e. compare findings with previous 
studies)  
 
- Most of the significant findings of the study would not be  significant after Bonferroni 
correction (which is a further limitation)  
 
- On some occasions the language of the paper needs improvement  
 
 
Minor points:  
 
- Line 26, for clarity, metabolic risk factors required or inclusion should be provided  
 
- All exclusion criteria should be better defined (for instance is anti -HBc positivity already a 
hepatitis B infection?)  
 
- Some data might be better presented as graphs (for better readability; this is a non -essential 
suggestion)  
 
Are the methods appropriate and well described?  
If not, 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.  
 
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 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 assess  the statistics  
 
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 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 interests  
 
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