Review for 10.1186/s12876-020-01402-z (2020)

Reviewer ’s report  
 
Title: Using the preoperative prognostic nutritional index as a predictive factor for non -cancer -
related death in post -curative r esection gastric cancer patients: A retrospective cohort study  
 
Version: 0 Date: 26 Jan 2020  
Reviewer:  Daniel  Reim  
Reviewer's report:  
Interesting paper investigating on the influence of PNI for gastric cancer patients. However, 
several issues should be addressed:  
1. Please provide a STROBE compliant manuscript along with STROBE statement.  
2. Abstract: Conclusion is not justified by data presented (see also "Results): Authors state that 
there was a significant shorter OS for low PNI in stage II: P -value is 0.073 (whi ch cannot be 
considered statistically significant). Therefore the conclusion must be that PNI is effective only 
in stage I GC patients.  
3. Introduction: The epidemiology data displayed is outdated, there is newer data for GC, which 
shows that GC is not the  second most common malignancy. Please update (f.e. GLOBOCAN 
data).  
4. Please provide data on the whole cohort: How many patients were treated in the dedicated 
period, how many fulfilled your "inclusion" criteria. How many were stage IV/metastatic, how 
many were R1/R2, etc. Please describe IRB process and approval.  
5. Results: line 135/136: The statement "...that TU markers tend to influence OS" is an 
interpretation and should be moved to the Discussion section. Anyhow, this statement does not 
make real se nse, as it is not quite clear in how far TU markers are able to influence survival just 
by being increased. Line 146/147: As indicated for the abstract, this statement is wrong: A p -
value of 0.073 does not represent statistical significance. Please correct .  
6. Tables: There is a lot of missing data, which have to be analyzed to take the conclusions the 
authors provided: Please add data on comorbidities, postOP complications. Length of stay, tumor 
size, tumor grading, lymphatic vessel infiltration, number o f nodes dissected. Proportions of 
patients undergoing D1+/D2. Further, data presentation should be improved: Please show 
numbers (n=) and percentages (%). BMI is not correctly reported: If using median, please do not 
display mean values. The "≤" symbol has  to be replaced by "≥". The additional data should also 
be included in the uni - and multivariate analyses.  
7. Multivariate analysis: The case number may be too low to draw robust conclusions: In stage II 
there were only 38 and in stage II only 30 patients.  
8. Discussion: Please discuss methodological limitations of the data in more detail. Please do not 
advoca te for blood transfusions as improvement of nourishment status. This is outdated. Please 
comment on the short FU time of only 3.5 years. For robust conclusions a 5 year FU is 
recommended. Conclusion has to be corrected for the above mentioned reasons.  
 
 
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 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 manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please speci fy 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 manuscr ipt: 
 
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, f ees, funding, or salary from an 
organisation that may in any way gain or lose financial ly from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation t hat 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 f or 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 compet ing interests' 
below. If your reply is yes to any, please give details below.  
 
No competing interests  
 
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