Review for 10.1186/1471-230X-10-5 (2010)

Reviewer's report
Title:Differences in Rebleeding Behavior after Endoscopic Band Ligation: A
Retrospective Analysis
Version: 1Date:15 June 2009
Reviewer: Justin Cheung
Reviewer's report:
Major Compulsory revisions
1. Significant selection bias may be present by analyzing the data and outcomes
per Band Ligation procedures, and not per individual patients. Therefore certain
patients may be at higher or lower risk of rebleeding and potentially could have
been included into analysis more than once. Results should be analyzed by
patient first episode, and only included in analysis once.
2. Selection bias potential has also not been fully assessed because there is no
Table or description in the text comparing pertinent potential confounders and
baseline characteristics between the elective vs acute band ligation. For
example, how does the mean number of bands placed compare in elective vs
acute band ligation procedures? If more bands are placed during acute banding
then one would expect that more band ulcer bleeding would occur (especially
since the authors state that they showed that more bands are associated with
higher risk of ligation ulcer bleeds). Additionally, what are the other potential
confounders to bleeding such as platelets, INR, Creatinine level in both groups?
3. Selection bias may also be present if patients who underwent band ligation but
died were excluded. These may be higher risk liver disease patients. It may be
important to report the mortality rates in each group and causes of mortality. An
alternative but less helpful if it is truly non-related mortality causes, is to describe
the causes of death in the excluded patients.
4. In order for the reader to determine generalizability/external validity, the
severity and causes of liver disease in both groups should be presented (ie age,
gender, child pugh or MELD score, % primary vs secondary prevention, etc)
5. Use of Somatostatin analogues and beta blockers should be presented since
this is known to affect rebleeding rates.
6. Length of follow up in each group needs to be presented. The rates of
rebleeding can be dependent on follow up length.
7. How were other causes of potential bleeding handled if they were present at
the same time. Not infrequently, gastric varices, portal hypertensive gastropathy,
and peptic ulcers are also present and may interfere with rebleeding assessment.
8. Post Banding bleeding in patients undergoing Elective Primary prophylaxis
Banding is not technically “Rebleeding” as they have not bled before.
9. Statistics – should clarify if a two tailed or one tailed p value was used.
10. Should the Kaplan-Meier statistical comparison of both curves be using a
different test than Mann Whitney test (ie log rank instead?)
11. Introduction can be more concise and related to the objectives of study,
rather than review esophageal varices management. Introduction should not
include a concluding statement (ie as in the last sentence)
12. Methods section – the patient inclusion and exclusion results /numbers
should be in the Results section.
13. Discussion - Authors should comment or provide background evidence on
the variability in practice with band ligation. My experience at several institutions
in different countries is that elective banding is not an inpatient procedure and
that patients are not routinely observed until all bands have fallen off. I suspect
that most units do not do this.
14. Im not sure that the comparison of recurrent variceal bleeding post variceal
bleeding banding vs elective banding (primary prophylaxis or secondary
prophylaxis) is considered new information. It is well known that high rates of
variceal rebleeding (up to 60% in 1 year if no treatment) occur after an initial
episode and that highest rates of variceal rebleeding are within the first 30 days.
Perhaps focusing on band ulcer bleeding rates between both groups may be
more informative.
15. Concluding that inpatient variceal bleeders should be kept in hospital for 11
days seems problematic for this retrospective study. Retrospective studies are
rarely conclusive and definitive. This statement has significant resource utilization
and cost implications. It may be more appropriate to suggest that at least 4 days
of hospitalization should be considered given the data and study design.
Similarly, the abstract conclusion of “surveillance for 11 days” does not seem to
flow logically from the results presented in the abstract. Moreover, the % risk of
rebleeding after acute band ligation appears to be 22/182 (12.1%). 14 of these
rebleed within 4 days. Then 8 of 182 rebleed after 4 days (ie 4%). It may be
difficult to conclude that keeping patients in hospital for another 7 days to capture
4% of total rebleeding among acute bleeders is reasonable.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interest