Review for 10.1186/s12876-016-0565-6 (2017)

Reviewer ’s report  
 
Title: A significant cancer burden and high mortality of Intrahepatic Cholangiocarcinoma in 
Thailand: a nationwide database study.  
 
Version: 0 Date: 24 Sep 2016  
 
Reviewer: Teng -Yu Lee  
 
Reviewer's report:  
 
Major concerns:  
1. Study novelty: No nove l information could be provided for international journal readers from 
this study.  
2. Limitations of the Nationwide Hospital Admission Database: The authors should introduce 
this database in details, including the coverage rates, reimbursement limitations,  and 
validation in published studies. For example, this database seems to be limited in the private 
medical systems and the south region. Is this study really a "nationwide" study?      
3. Incomplete CCA definition: CCA was defined by ICD -10 C221 in this st udy, and only 
intrahepatic CCA was included by this definition.  
4. Inadequate epidemiological methodology: The authors reported that the disease burden of 
CCA patients in Thailand was 0.65% of inpatients with gastrointestinal (GI) diseases. 
However, patient s with GI diseases were widely various, and we cannot draw a whole picture 
of the CCA incidence by this description. Standardized incidence ration (SIR) may be used 
for drawing a real nationwide picture.    
5. Risk factors of CCA: The authors introduced a l ot of background information regarding 
major risk factors of CCA development, such as liver flukes, in the manuscript, but no data 
of CCA risk factors was provided.   
6. Tumor staging: The authors introduced a lot of background information regarding tumor 
staging in the manuscript, but no data of CCA tumor staging was provided.  
7. The cost of hospitalization: International journal readers will not know 160 USD per 
admission in Thailand is high or low, and a simple cost description is not informative.  
8. Multiv ariable analysis for overall mortality: In this manuscript, length of hospital stay of >7 
days was related to all -causes of death. Length of hospital stay is not a useful marker for the 
clinical applications in real world; analyzing the reasons why patient s need a longer hospital 
stay is more reasonable.  
9. The authors declared that eating well -cooked food was important, but the analyses in this 
study did not provide related information.    
10. Patient numbers in Table 1 were inconsistent and not clear.  
11. The discussion was redundant and not logical.  
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.  
 
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.  
 
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, o r 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.  
 
I declare that I have no competing interests  
 
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