Review for 10.1186/s12876-022-02558-6 (2022)

Title: Adverse outcomes after non-hepatic surgeries in patients with alcoholic liver diseases: a
propensity-score matched study
Version: 1 Date: 05 Mar 2022
Reviewer's report:
The study used retrospective data from National Health Insurance scheme to assess the impact of
alcohol-related liver disease (ALD) on post-operative complications and in-hospital mortality.
Abstract:
1) Phrase 'propensity score matching' is duplicated in the methods.
2)  'with out no ALD' is also incorrect, please correct.
3) First line of the results is confusing. Mentioning a list of complications and giving one Odds
ratio (which is in fact related to just in-hospital mortality) may be misunderstood as the OR for
composite outcomes. So, rephrase this to clarify.
4) similarly, it is unclear whether OR described for alcohol dependence syndrome is with or
without ALD or both.
5) In conclusion, 'protocols for peri-operative care' (rather than just post-operative care should
be stressed.
6) Introduction: First paragraph isn't contributing much to the focus of the study, so can be
omitted.
Methods:
7) Clarify whether data was anonymised or pseudoananymised (what do you mean scrambled).
8) please provide brief details of what the method of coding of the procedures are, how did
non-hepatic cases were identified and if the coding of 'non-hepatic surgical procedures' as well
as other codes used for evaluating the outcomes have been validated previously or as a part of
current study. Authors list references 39, 40, but, the points above should be explicitly addressed.
9) explain the reasoning behind the age cut-off of 20 years.
10) Authors state that- To identify patients with ALD more clearly, the current study required
at least one medical care visit with a physician’s diagnosis of ALD within the 24-month
preoperative period of the index surgery. This is an important exclusion as patients who had
shorter period of diagnosis before surgery may have a different outcome. Authors need to explain
the reasoning behind this more clearly. In addition, if possible, data can be analysed to investigate
impact of the duration between the diagnosis and surgery.
Results:
11) there is no details on the drinking status of participants. I assume the information was not
extracted or not available from the claim database. Please clarify.
12) I see the OR for alcohol dependence syndrome; was this with or without ALD or both?
13) was there any difference between emergency versus elective surgery?
14) could age be included as a continuous variable in the model?
15) why is 90% of the cohort are men? does this match the prevalence of ALD in the population?
Discussion:
16) The sentence doesn't make sense- 'Due to indistinguishable liver conditions during hepatic
surgery, we excluded hepatic surgery in our analysis'.
17) Authors mention the validation of the database previously. This should be listed as a strength,
not a limitation.
18) The study includes the various spectrum of liver disease ranging from alcoholic fatty liver
disease, cirrhosis to decompensated liver disease. Yet the author combined them as a single
entity to calculate HR in table 2 and 3. How can the author justify this?
19) Overall discussion should be re-written structured as a) stating salient findings, b) strengths
and limitations c) how these findings compare or contrast with the literature and d) what the
clinical implications are. The manuscript does benefit for editing for language and grammar.