Review for 10.1186/1471-230X-12-55 (2012)

Reviewer's report
Title:Risk of inflammatory bowel disease following a diagnosis of irritable bowel
syndrome
Version: 1Date:1 November 2011
Reviewer: Mark Lazarev
Reviewer's report:
Porter et al. set out to look at the risk of developing IBD after a diagnosis of IBS,
as well as the risk of developing IBD after an episode of IGE after IBS diagnosis.
Overall the article is well written. The authors have expanded on their findings of
the association of IBD with IGE from a case control study. The finding of a greatly
increased risk of IBD in patients with IBS are similar to those published earlier in
Garcia Rodriguez et al, a population cohort study. However, this article uses a
different population, and was more rigorously performed. The most unique
aspect is the use of the well-defined IBS cohort which includes a negative
colonsocopy. For the most part, this minimizes the bias that IBD was already
present. Additionally, the authors found that the risk of IGE was greater in IBS
patients, although this finding is biased by health care seeking behaviour bias
among IBS patients.
I think this article is close to ready for publication. My largest criticism deals with
the discussion, which frequently goes off topic and needs to be more targeted. I
am recommending the following edits, all of which fall under minor essential
revisions:
1) Minor essential revision: Methods - page 5, 2nd paragraph, 10th line - please
define MTF
2) Discretionary revision: Results - page 9, 1st complete paragraph - I would
eliminate the second half of the paragraph starting with "Among those with IBS
who reported diarrhea during . . . . " This data is just distracting and does not add
to your overall message
3) Discretionary revision: Discussion - page 10, 3rd paragraph extedning to page
11. This paragraph needs to be greatly trimmed down to a few lines
4) Discretionary revision: Discussion - page 13, 2nd complete paragraph
extending to page 14 - there is too much detail here. My trying to explain away
every covariate, you are losing focus. It becomes very distracting. I would edit
this down to a few lines.
5) Minor essential revision: Discussion - page 15, 1st complete paragraph, line
13 - should this sentence end with "where IGE risk is high"? I think this is a typo
6) Discretionary revision: Discussion - page 15, 1st complete paragraph
extending to page 16. The second half of the paragraph starting with "Travelers
from developed countries and deployed military . . . " is all speculative and
distracting. I would remove.
7) Discretionary revision: There were a couple covariables not mentioned that I
was wondering if you looked at:
a) duration of IBS diagnosis
b) IGE prior to IBS diagnosis - esentially, is it possible that patients with
post-infectious IBS are at higher risk for developing IBD than patients without
post-infectious IBS?
8) Disretionary revision: Did you look at different Crohn's subdiagnoses - 555.0,
555.1, 555.2, and 555.9? I would expect patients would more likely have colonic
involvement than small bowel involvement. In the future, are you planning on
reviewing the charts of the patients who developed IBD to gain more data on
demographics, phenotype, etc? It seems it would be worthwhile.
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