Review for 10.1186/1471-230X-9-98 (2009)

Reviewer's report
Title:Sensitivity is not an intrinsic property of a diagnostic test: empirical
evidence from histological diagnosis of Helicobacter pylori infection
Version: 1Date:10 August 2009
Reviewer: Lyudmila Boyanova
Reviewer's report:
The article is well written and focuses an interesting topic, involving the reasons
for negative results of the diagnostic tests for H. pylori detection and the
influence of different factors to be taken into account during the diagnosis of the
infection. However, a Minor Essential Revision with additions and clarification in
the Methods, Result and Discussion sections, is necessary to improve the
manuscript.
Questions and Suggestions
1. Methods. What were the eradication regimens for the patients? If data are
available, please, describe the combinations. The regimen, antibiotics included,
dosage, patients’ compliance and other factors can be associated with the
unsuccessful eradication.
2. Methods. How many PPI users were involved from both countries? If the
authors have the appropriate information, the data can be added to the
manuscript. It is known that the accuracy of the diagnostic tests can decrease in
PPI users.
3. Methods. “Two ml were used for each PCR”- is it correct?
4. Methods, page 5: Can the difference between the specimens for the PCR in
both countries (frozen antral biopsies vs. formalin fixed paraffin embedded
biopsies) influence the results?
5. Results. Were Helicobacter suis, H. bizzozeronii, Helicobacter felis and
Helicobacter salomonis (ex-H. heilmannii bacteria) detected? Coinfections with
H. pylori and H. felis have been reported in African populations. Were coccoid
forms (suggesting possible degenerative forms of H. pylori) found in the negative
specimens?
6. Results, Page 6: The statement about the frequent antibiotic use in
Mozambican patients should be explained by DIDs of the antibiotics (with activity
against H. pylori) in both countries.
7. Discussion, Page 7: The sensitivity of the histological assessment of H. pylori
infection was considerably lower in Mozambique than in Portugal, which is
explained by a lower density of colonization because of frequent antibiotic usage.
How could be explained, in this context, the difference of infection rates by
histology between Ghana and Uganda?
8. How many patients had ulcers and how many had non-ulcer disease? Could
the type of the disease be associated with the density? The articles of Molnar et
al. (2008) and Gallo at al. (2003) can be considered.
9. Discussion, Page 8: The percentage of Mozambican patients with atrophic
gastritis was given but what was the percentage for the Portuguese patients?
10. Discussion, Page 8: If the sensitivity of the histology is better in Ghana than
in Uganda, does that means that in Uganda the consumption of antibiotic is
higher than that in Ghana? What are the data and the possible reasons for this
difference?
11. What is the incidence of gastric cancer in Portugal and Mozambique? Can
the higher prevalence of mild infections in Mozambique than in Portugal be
associated with a lower incidence of cancer in Mozambique?
12. References. Fewer than 40% of the references are from the last five years.
More recent reviews (e.g. Megraud & Lehours, 2007; Saad & Chey, 2005 etc.)
and articles can be involved in the References.
Level of interest: An article of importance in its field
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 interests.