Review for 10.1186/s12876-025-03887-y (2025)

Title: Independent effects of the hemoglobin-to-red blood cell distribution width ratio on 180-
day mortality in critically ill patients with gastrointestinal bleeding: analysis from the MIMIC-
IV database
Version: 4 Date: 22 Feb 2025
Reviewer's report:
This study explores whether HRR could serve as a prognostic factor in patients with GIB.
While the results of this study could be a useful approach to the existing problem, there are some
concerns. My comments are below
Major comments:
#The authors evaluate 180 day mortality using HR, but this is not accurate. HR represents the
likelihood of death over the entire observation period. If the study aims to present 180-day
mortality, it is equivalent to a 3-year mortality rate and should be expressed as a percentage rather
than HR. Please revise the manuscript accordingly. 180 day mortality may give the impression
that it is the mortality rate at 180 days.
#The study population consists of patients diagnosed with GIB, and mortality is one of the
endpoints. The authors investigate whether HRR functions as a marker for mortality, but
information on whether the cause of death was GIB is highly important.
#Generally, dividing a continuous variable into quartiles and analyzing four groups is not
scientifically appropriate. Since this is a single-center study, it is unclear whether dividing
into quartiles would be applicable to other institutions. Instead, it would be more scientifically
valid to use clinically relevant cutoff values for stratification. A two-group division would be
sufficient instead of quartiles. Additionally, in the "at risk" section, numerical values such as
1-4 should be properly described rather than simply listed.
#This study aims to explore the significance of HRR in patients diagnosed with GIB. Generally,
patient characteristics at 180 days after diagnosis are unnecessary for the study’s objective.
#What is the starting point for the time variable used in this study? Does it begin at the date
of GIB diagnosis? The interpretation of results differs significantly depending on whether the
study starts from the diagnosis date or if GIB was present at the observation date.
#In the introduction, the authors discuss the relationship between GIB, depression, and frailty.
However, this discussion is entirely unrelated to the current study.
#Description for median survival time (95% ) are necessary.
Minor comments:
#When inserting figures and tables in the Word file, please use Word’s section breaks to improve
readability. Additionally, adjust table orientation (e.g., landscape format) if necessary for better
visualization.
#The authors state that HRR was "stable" across various subgroups, but "stable" is not the
appropriate term in this context. The correct term is "consistent."
#There should be a half-space between "95%" and "CI" as well as between "HR" and "(95%
CI)." Additionally, numerical precision should be consistent across tables and figures (e.g., HR
values differ between Figure 3 and Table 3).
#ANOVA only indicates whether there is a difference among groups but does not specify which
groups differ or which has the largest value. Therefore, it is generally inappropriate to use
ANOVA to determine which specific group is significantly larger.