Review for 10.1186/s12876-024-03380-y (2024)

Title: Application of antithrombotic drugs and risk factor analysis in ICU patients with lower
gastrointestinal bleeding from MIMIC-IV
Version: 4 Date: 05 Jul 2024
Reviewer's report:
The manuscript provides lots of useful information about the application of antithrombotic drugs
and risk factor analysis in ICU patients with lower gastrointestinal bleeding (LGIB). However,
it would be great if the authors could make some major and minor revisions as suggested below:
Major points:
- LGIB is traditionally defined as the site of bleeding distal to the ligament of Treitz. In another
classification, LGIB refers to bleeding originating from the cecum to the anus. Patients with
LGIB can present with melena without hematemesis or hematochezia. Please describe the
clinical presentations of LGIB and define LGIB in detail.
- How could the authors diagnose LGIB? When was the colonoscopy, angiography, or surgery
indicated?
- The exclusion criteria were patients with combined upper or middle gastrointestinal bleeding.
How could the authors diagnose acute upper and middle gastrointestinal bleeding?
- The phrase “those with combined upper or middle gastrointestinal bleeding” means patients
suffering from both LGIB and upper/middle gastrointestinal bleeding. Can the authors explain
it clearly?
- Why did the authors exclude patients with complications from pregnancy, trauma, poisoning,
transplantation, and HIV? When the authors excluded them, the results regarding the prognosis
of patients, especially mortality, would be affected significantly. Please clarify it.
- Did the authors choose the patients presenting with LGIB at admission or LGIB occurring
during hospitalization? Please explain it.
- The authors wrote “Rebleeding was defined as a hemoglobin decrease of more than 20g/l from
admission”. However, the initial hemoglobin value at admission may not accurately reflect the
extent of blood loss and it can drop after 24-72 hours because of delayed equilibration with
extravascular fluid. How could the authors differentiate rebleeding from this phenomenon or
persistent bleeding? Please clarify and define the variable “rebleeding” in detail.
- Did the criteria for the repetition of endoscopic procedures include poor bowel preparation?
- The reviewer only found diverticulosis and inflammatory bowel disease as the etiologies of
LGIB in the methods and results. Are there other causes of LGIB in the study?
- Please define in-hospital mortality, hospital stay length, and ICU stay length.
- Did the patients die of uncontrollable bleeding or severe comorbidities?
- The indications of antithrombotic drugs include treatment of acute myocardial infarction,
primary or secondary prevention of coronary disease, or management of venous thrombosis, etc.
The reviewer thinks the dose depends on the purpose of using these drugs. Accordingly, it affects
the progress and severity of LGIB. Please analyze the indication and the dose of anticoagulants
and antiplatelets.
- When were the patients with LGIB treated with anticoagulants and antiplatelets?
- Some medications such as NSAIDs, corticoids, heparin, or dual antiplatelets can influence the
progress of LGIB. Did the patients manage with these drugs? Please make it clear.
- In the results, the authors wrote “Patients on antithrombotic drugs typically had fewer instances
of LGIB as a primary diagnosis, fewer bleeding events due to diverticula, were older, had
a higher proportion of males, and more often had comorbidities such as myocardial infarct,
congestive heart failure (CHF), peripheral vascular disease (PVD), diabetes, and renal disease”.
Which group of patients were compared with patients on antithrombotic drugs? It may be
difficult for the readers to understand the structure and meaning of this sentence. Please rewrite
it.
- Which data were missed during retrospective data collection?
- The authors wrote “As the study population consisted of ICU patients, there might be some
bias”. Which bias did the authors mention in this study?
Minor points:
- The introduction and aims should be added in the first paragraph of the manuscript.
- Please rewrite some sentences such as line 6-12 of the first paragraph in the introduction, line
1 of the first paragraph, and line 1- 4 of the fifth paragraph in the discussion.
- Some grammar mistakes, noun phrases, articles, and parallel structures should be revised.
Please proofread the manuscript thoroughly.