Review for 10.1186/s12876-021-01714-8 (2021)

Reviewer’s report
Title: 
Plasma cell free DNA methylation markers for Hepatocellular Carcinoma
surveillance in patients with cirrhosis: a case control study
Version: 
0 
Date: 
02 Jan 2021
Reviewer's report:
There are serious problems with this work. The number of patients given in the
title of the table (HCC = 61, Non-HCC = 102) and subheadings (Child-class: 60
+ 43 = 103, Etiology of cirrhosis: 26 + 2 + 20 + 33 + 23 = 104 , BCLC Stage: 10
+ 39 + 11 = 60 etc) the number of patients given do not match. This is a very
serious mistake.
Which statistical analysis method was used in this study? the authors have not
written a single word on this subject.
In the methodology section, it was stated that Group II consisted of 60 patients
with HCC. However, it has been stated in a few xections that this group consists
of 61 patients.
In the summary section, it was stated that 41 HCC and 45 Non-HCC patients
were included in the training test group. But in the methodology section, these
numbers are given as 41 + 46. Which one is right?
My suggestion to the authors is this:
Please, add statistical analysis section
Check your number of patients and give consistent numbers
How did you create Table-2? Is your reference test CT or biopsy? (which should
have a biopsy)
In Table-1, you compared the two groups, but you did not give the p value. Add
a column for the p value to this table.
By which statistical analysis method did you calculate the patient and control
groups? Such a study cannot be expected to be retrospective. Therefore, a certain
protocol must be followed in prospective cohort studies.
Finally, I recommend you to take advantage of the following studies on HCC.
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Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
No
Are the methods sufficiently described to allow the study to be repeated?
No
Is the use of statistics and treatment of uncertainties appropriate?
No
Is the presentation of the work clear?
No
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
No