Review for 10.1186/s12876-020-01472-z (2020)

Reviewer’ s report
Title: Impact of low skeletal muscle mass index and perioperative blood transfusion on the
prognosis for HCC following curative resection
Version: 1Date: 17 Jul 2020
Reviewer's report:
Impact of low skeletal muscle mass index and perioperative blood transfusion on the prognosis for
HCC following curative resection (BMGE-D-19-01097R1)
Please better explain how you constructed the PSM in the statistical analysis part. Which variables
did you use for performing the multivariable logistic regression? Which was the caliper? Whichwas the PSM method specifically adopted?
In this sentence there is a typo: "To overcome bias owing to the different distribution of covariates
among patients from the transfusion and nontransfusion groups, propensity score-matchedanalysis was performed using a multiple logistic regression model to predict the probability ofeach patient of being transfused on the basis of clinicopathological variables."instead of"To overcome bias owing to the different distribution of covariates among patients from thetransfusion and nontransfusion groups, propensity score-matched analysis was performed using amultiple logistic regression model to predict the probability of each patient being transfusion onthe basis of clinicopathological variables."
I have some concenrs on the construction of the multivariable models. Seven and six variables for
identifying risk factors for OS and RFS are too many for a population of only 139 cases. I suggest
considering to perform a backward conditional or backward wald method for reducing the numberof really significant variables. The risk is that the model is based on a too small number of eventsfor giving solid conclusions.
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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:
Needs some language corrections before being published
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