Review for 10.1186/s12876-024-03261-4 (2024)

Title: Proton pump inhibitor therapy after transcatheter angiography in refractory nonvariceal
acute upper gastrointestinal bleeding patients#a cohort study
Version: 0 Date: 02 Dec 2023
Reviewer:  Kenta Watanabe
Reviewer's report:
This large-scale observational study demonstrated that high-dose PPI therapy after TA for
refractory NVUGIB cases had no substantial impact on their outcomes. Although the study
design and results are noteworthy, there are concerns regarding methodology, interpretation,
and presentation that should be addressed. Please refer to the comments below.
Major
1. In the Study design, you described, "(3) 6 due to bleeding from gastrointestinal tumors
were excluded." However, in the Supplementary table 9, the analysis was performed excluding
patients with gastrointestinal cancer. Does this mean that patients with bleeding from
gastrointestinal lesions other than gastrointestinal cancer were excluded from the sensitivity
analysis? Please clarify.
2. In the Statistical analysis, why were the covariates used to calculate the propensity score
different from the balancing factors in IPTW? Generally, the same factors should be applied.
3. Throughout the tables, explanations about adjusting factors (independent variables) in
multivariable analyses were not provided in the table captions. Furthermore, are multivariable
analyses necessary after balancing using IPTW or PSM? Unless there are any additional factors
that need to be adjusted, I think it is okay to describe only crude ORs based on univariable
analyses after balancing.
4. What exactly is the time-dependent variable mentioned in the Statistical analysis? If there is
no relevant factor, delete the confusing description.
5. In the Figure 1, the abbreviation TAE is confusing. TAE seems to generally mean transcatheter
arterial embolization. In the Figure 1, it is described as transcatheter angiographic examination
(TAE). On the other hand, in the Table 2 and 3, it seems that TA, TAE, and targeted TAE are
used in the sense of embolization. These fluctuations in expression are extremely difficult for
readers to understand. Please clarify.
6. In the Supplementary tables 3, 6, and 7, although two different p values were listed, there was
only one parameter value, making the correspondence difficult to understand. You should list
the corresponding parameter values both before and after IPTW.
7. Regarding the results of subgroup analysis, it was mentioned that high-dose PPI treatment
shortened the length of hospital stay. However, according to the Supplementary table 7, it seems
to be longer with high-dose PPI group. If the original description is incorrect, the corresponding
description (fifth paragraph of the Discussion) should also be corrected.
Minor
1. When using an abbreviation, define it the first time it appears in the text, and use it consistently
thereafter. It is not recommended to define only in figures and tables. Additionally, abbreviations
used within tables should be defined in each case in the corresponding table caption.
2. Is the description “TA is a diagnostic stool and…” correct in the second paragraph of the
Introduction? Isn’t it a “diagnostic tool” instead of a “diagnostic stool”?
3. In the second paragraph of the Results, you mentioned that GBS was approximately 12, but
I think GBS is approximately 11.
4. In the Supplementary table 8, it seems that a comma between the upper and lower limits of
the 95% CI for 30-day all-cause mortality. Please confirm.