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 resection gastric cancer patients: A retrospective cohort study
Version: 1Date: 19 Jun 2020
Reviewer: Research Square Reviewer 1
Reviewer's report:
PEER REVIEWER ASSESSMENTS:OBJECTIVE - Full research articles: is there a clear objective that addresses one or several testable
research questions? (Brief or other article types: is there a clear objective?)Yes - there is a clear objective
DESIGN - Is the current approach (including controls and analysis protocols) appropriate for the
objective?Yes - the approach is appropriate
EXECUTION - Are the experiments and analyses performed with sufficient technical rigor to
allow confidence in the results?Yes - experiments and analyses were performed appropriately
STATISTICS - Is the use of statistics in the manuscript appropriate?
Yes - appropriate statistical analyses have been used in the study
INTERPRETATION - Is the current interpretation/discussion of the results reasonable and not
overstated?Yes - the author's interpretation is reasonable
OVERALL MANUSCRIPT POTENTIAL - Has the author addressed your concerns sufficiently
for you to now recommend the work as a technically sound contribution? If not, can furtherrevisions be made to make the work technically sound?Yes - current version is technically sound
PEER REVIEWER COMMENTS:GENERAL COMMENTS: Overall, the authors have improved the paper. The analyses give a
better sense that the prognostic nutritional index (PNI) is related to non-cancer mortality.
REQUESTED REVISIONS:
One minor concern is that the authors do not report the subdistribution Hazard Ratio (sHR) for thePNI effect from the Fine and Gray Proportional Hazards regression. This is a bit unusual as this
would seem to be a key statistic given the title's emphasis on non-cancer related death. Despite this
reviewer's suggestion, the authors chose not to include calibration or concordance statistics it
seems, which is a limitation of the paper.ADDITIONAL REQUESTS/SUGGESTIONS:The paper would be improved by reporting the subdistribution Hazard Ratio for the PNI effectfrom the Fine and Gray proportional hazards regression of non-cancer related mortality.
The authors might consider changing the term "multivariate" to "multivariable" throughout the
manuscript. The models the investigators used are more appropriately called multivariable modelsbecause only the time to event response variables in the models are considered random.
The investigators could clarify whether the p-values in table 3 are from simple univariate logistic
regressions or from a full-model multivariable logistic regression. The p-values in Table 3 are a bitdifferent than what one might obtain from a chi-squared or Fisher's exact test, suggesting that theymight be from a full model.
The authors might write that not examining calibration and concordance statistics is a limitation of
their work.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
YesDoes 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.
YesAre 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 furtherassessment in your comments to the editors.
I am able to assess the statisticsQuality of written English
Please indicate the quality of language in the manuscript:
Acceptable
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 thismanuscript, 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.
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 hasagreed to publication of their comments online under a Creative Commons Attribution Licenseattributed to Research Square and was paid a small honorarium for completing the review within aspecified timeframe. Honoraria for reviews such as this are paid regardless of the reviewer
recommendation.
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No