Review for 10.1186/s12876-020-01522-6 (2020)

Reviewer’s report
Title: 
High-density lipoprotein cholesterol is a predictor of survival in cirrhotic
patients with acute gastrointestinal bleeding: a retrospective study
Version: 
0 
Date: 
01 Sep 2020
Reviewer's report:
Cheng et al reported a study using HDL cholesterol as a predictor of survival in
cirrhotic patients with acute GI bleeding. While the study is interesting and may
be clinically relevant, I have several observations:
Major comments:
- The risk score does not incorporate the severity of bleeding itself, like vital
signs, amount of blood transfusion, length of ICU stay, the need of endoscopy
treatment, or the need of TIPS. What is the rationale, and does these scores
provide more insight than conventional bleeding score such as Rockall score or
Glasgow-Blatchford score?
- How did the authors choose the 4 variables? Is it due to multivariable analysis
based on Table 4? If so, please include the results of the multivariable analysis as
a new table or part of Table 4.
- The N-CGIB model include 4 variables: HDL-C, sodium, QTc prolongation,
and HCC. What is the relatively weight of each variable in predicting outcome?
- Why did the authors choose 6-week mortality as the endpoint? If the authors
use 7-day, 30-day or 90-day mortality as endpoint, would the results be
consistent?
- The authors can also consider another technique, time-dependent ROC analysis.
This may better examine the predictive ability of a scoring system over a certain
amount of time (for example, 7 to 90 days)
- Although the authors used cirrhosis-specific equations in calculating the QTc,
but are these equations validated in patients with tachycardia (due to bleeding)
which itself can affect QT/QTc? Do the authors have baseline EKG and baseline
QTc information available?
- What are the etiologies of bleeding? Does the ability of N-CGIB change due to
variceal versus non-variceal bleeds?
Minor comments:
- I would put the N-CGIB score in Table 1 so that readers can understand more
easily.
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