Review for 10.1186/1471-230X-11-7 (2011)

Reviewer's report
Title:Helicobacter pylori infection and circulating ghrelin levels - A systematic
review
Version: 1Date:26 April 2010
Reviewer: Barbara Nawrot
Reviewer's report:
The paper by Nweneka and Prentice is a systematic review on the influence of
Helicobacter pylori colonization/infection on the level of circulating ghrelin. This is
a kind of review paper (the form which is not preferable at BMC
Gastroenterology), in which the Authors analyze the data on ghrelin level in
serum or plasma in H. pylori positive and non-infected patients, also after H.
pylori eradication, in context of many factors like region of studies, patient healthy
or sick, gender, age, etc. One has to note that the relevant data available in the
literature are inconsistent. The Authors tried to analyze systematically the
available data and to make, if possible, generalized conclusions. The Authors
asked three questions and extracted available data from selected papers
(claimed to be present in the screened databases before December 15, 2009) to
make statistical analysis and meta-analysis. At first glance the paper looks good
– all the tables are well designed, the analyses are done correctly, proper
methodology and tests are used, clear criteria of inclusion and exclusion of data
are applied, concise and informative Results and Discussion sections are
included.
However I have some critical issues. The first is that the performed analyses
allowed for making only one general conclusion that the level of circulating
ghrelin is dropping in H. pylori positive patients in comparison to non-infected
individuals. Due to the lack of sufficient amount of data several aspects of the
investigated problems are still not clear and Authors stress on the requirement
for further studies. The paper might be interesting for readers, only when the
reference section is brought to a proper order. The present mess with the
references cited is absolutely unacceptable and Authors should make proper
corrections!
My detailed concerns about this paper are as follows:
1. The paper cited as a conference abstract has been already published as a full
paper J Korean Med Sci 2010 Feb; 25(2), 265-71, epub Jan 22, 2010 by Lee ES
et al. The Authors should make correction when discussing this contribution to
their analysis.
2. Isomoto’s papers are not cited properly – four papers are listed in Figures
while only two are in the list of references. Correct these citations also in Table 4.
3. Nishi’s 2005 paper is missing in the list of references
4. What does it mean “Study Team” in Tables 4 and 8? Do Isomoto et al., Nishi
et al. and Osawa et al. constitute the same study team described as ”C”?
5. Shiotani’s 2005 paper is missing in the list of references
6. Jun et al 2007 is missing in the list of references
7. Ref 12 and 18 are identical (the title with an error)!!
8. Gender difference in circulating ghrelin in H. pylori patients is discussed in
Chuang CH et al paper, Helicobacter 2009!!! (not cited!)
9. D’Onghia et al 2007 paper is missing in the list of references
10. Gao et al 2009 paper is missing in the list of references
11. Czesnikiewicz-Guzik et al 2005, Konturek et al 2006, Cindoruk et al 2007, de
Martel 2007 papers are missing in the list of references
12. Table 4 has many wrong citations of the papers, and in addition the number
of analyzed teams/samples is not 23 but 19!!!
13. Several papers cited in table 8 are missing in the list of references (Cindoruk
et al 2007, Kawashima et al 2009)
14. The last paper mentioned above should be discussed in the context of
circulating ghrelin level and the histopathological changes.
15. Importantly the Authors do not pay enough attention to the dependence of
ghrelin level on the patients’ gender and the H. pylori strain virulence. In this
context at least one more paper evaluating gastric ghrelin in H pylori positive
patients related to sex and region of the stomach should be included into
analysis; Stec-Michalska K et al World J Gastroenterol 2009, Nov 15
16. More discussion on the mechanism of release of the hormone is needed
when comparing the levels of circulating and gastric ghrelin.
17. Editing issue: H pylori is mostly written in Italic and with “full stop” after “H”
(H. pylori)
18. It is more proper to use “the site of colonization” instead of “the site of
infection” when discussing H. pylori localization in the stomach
19. The title suggests that only circulating ghrelin will be evaluated while gastric
ghrelin is also discussed.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
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 interests