Review for 10.1186/s12876-022-02198-w (2022)

Title: Effect of alcohol on clinical complications of hepatitis virus-induced liver cirrhosis: a
consecutive ten-year study
Version: 1 Date: 03 Jan 2022
Reviewer's report:
Dear Editor,
Abassa et al wrote a paper on the results of a retrospective cohort study made in a tertiary center
for hepatology of Southern China, with the aim of verify the effect of alcohol consumption
on virus-induced liver cirrhosis. To do so, they retrospectively enrolled about 22300 subjects
diagnosed with liver cirrhosis over a ten-year time span (2010-2019) by identifying them with
ICD codes. They then divided their population in five groups on the basis of the cirrhosis
etiology: ALD, HBV, HCV, ALD+HBV, ALD+HCV and compared these groups between each
other on regard of liver disease complications (HCC, variceal bleeding, infections, et cetera).
They concluded that alcoholic liver disease worsen the natural history of cirrhosis.
The paper has some elements of interest, first of all the high number of patients enrolled,
nevertheless there are several points of discussion:
Major points:
1) Even if the authors provided a definition of what they intend for “ALD”, they didn’t provide
how they assessed the presence of ALD: being this a retrospective study made by collecting
ICD-10 codes, how the alcohol consumption was collected? By ICD codes? By reviewing each
medical record? This should be clarified.
2) The authors state that ALD presence was inferred by an unsafe alcohol consumption lasting
at least 5 years, and they also provided data on alcohol abstinence. Nevertheless, no data were
provided on the overall mean duration of this consumption, that may be a precious information,
that could also be an independent factor able to influence the patients’ outcomes.
3) Were the subjects enrolled outpatients or inpatients? If the medical records were collected
between subjects admitted to the hospital as inpatients it should be very likely they were admitted
for a complication of their liver disease. This fact could represent a very important selection
bias, difficult to overcome. The hospital admission for liver related events should be reported
and evaluated in the multivariable analyses.
4) Alcohol consumption (not only unsafe consumption, but every level of consumption) is a
well-known cofactor of liver disease progression which has been extensively studied in the past.
The authors should consider the redraft the introduction section and the abstract in which they
state that the coexistence of alcohol with viral diseases “has not been thoroughly studied”. It
may be more appropriate to state that, even if it has been studied, controversies already exist.
5) The Multivariable analyses investigating the association with HCC didn’t include important
parameters that are well known independent factors already known to be associated with HCC
as, in example, transaminases or the presence of type 2 diabetes mellitus.
6) No data on mortality are provided. Being a ten-year study on cirrhosis (with a high prevalence
of decompensated subjects) this is a major limitation.
7) seven tables and 2 figures are too much. It could be useful to insert some of them in
the supplementary material (ie table 5 is redundant with figure 2, (one or another could be
eliminated).
8) There are some typos among the paper that should be corrected, and a mother-tongue English
revision may render the paper more readable.