Review for 10.1186/s12876-017-0609-6 (2017)

Reviewer ’s report  
 
Title: The inverse effect of meal intake on contr olled attenuation parameter and liver stiffness as 
assessed by transient elastography  
 
Version: 0 Date: 11 Jan 2017  
 
Reviewer: Kednapa Thavorn  
 
Reviewer's report:  
 
Summary  
The manuscript reports the results of an experimental study assessing the impact of meal intake 
on the degree of steatosis m easured by controlled attenuation parameter (CAP) and the level of 
stiffness measured by transient elastography (TE) in 40 patients with chronic liver diseases who 
underwent a percutaneous liver biopsy at the liver clinics of one teaching hospital in Thail and. 
The study shows that CAP and LS values were influenced by meal intake and that CAP and LS 
values returned to the baseline within 150 minutes following the meal. Overall, the manuscript is 
well-written. The study is innovative as it shows whether food intake can influence the CAP and 
LS values and ultimately the diagnosis of liver steatosis and liver fibrosis.  
 
Major comments  
1. The study shows that the CAP values decreased after meal intake. This finding did not 
support the study's hypothesis indicating that CAP values would be increased after food 
intake. Could the authors discuss why this is the case? As the effect of food i ntake on CAP 
values is an innovative aspect of this study, the authors should emphasize on this result in 
the discussion section. The current version of the discussion section is solely focused on LS 
results.  
2. As pointed out in the background section, th e accuracy of CAP measurement can be 
influenced by various factors, such as high BMI and alcohol drinking. Were these factors 
adjusted in the analysis? How they were adjusted for?  
3. Why liquid meal was used as opposed to solid meal? Given that the study u sed liquid meal, 
are the results of the study generalizable to actual practices where patients may have solid 
meal before the test?  
4. Under the statistical analysis section, the authors indicated that they used the multilevel 
mixed model approach. Why thi s statistical technique was chosen? Did the authors adjust 
for any confounding factors? Did a small sample size has any impact on the results of 
statistic tests?  
5. On Page 7, Line 154, the authors mentioned that "LS and CAP measurement were obtained 
simu ltaneously after overnight fasting". How many hours participants were asked to fast 
before having the measurement? Would the fasting duration affect the baseline CAP or LS 
values? Why and Why not?  
6. As the study was based on a small sample size and a sing le centre, could the authors please 
comment on the generalisability of the results of this study to other settings in the discussion 
section?  
7. The authors should add the lack of control group as one of the study limitations.  
 
Minor comments  
1. On page 5 , Line 99, "the effect of a meal on CAP…" should be revised to "the effect of a 
meal on CAP value..". Similarly, the following sentence: "we hypothesized that CAP might 
increase.." should be revised to "we hypothesized that CAP value might increase..".  
2. On Page 7, Line 129 - 130, the authors indicated that "Liver biopsy was performed within 
four weeks of the study". This sentence is unclear. Did the sentence refer to within four 
weeks of the study recruitment?  
3. Do Figure 1 to 3 represent mean or median CAP/LS values? Please specify in the title. Each 
data point should include 95% CIs (if mean were reported) or IQR (if median were 
reported).  
4. Figure 1, why there were only 3 p -values for LS values? Similarly, why only 2 p -values and 
1 p-value were shown  in Figure 2A and 2B?  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the wo rk 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 editor s. 
 
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 publi cation 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 curr ently 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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