SNAPSHOTS FROM THE
Robin Spiller, MD, is professor of gastroenterology, NIHR
Nottingham Digestive Diseases Biomedical Research Unit,
Nottingham Digestive Diseases Centre, University of Nottingham,
England. He has no relevant conflicts of interest.
The phenomenon of IBS de- veloping after a bout of gas- troenteritis (postinfectious [PI]–irritable bowel syn- drome) was first reported in 1950 and subsequently elaborated by studies from Oxford (Q J Med.
1962;123:307-22), Sheffield (Gut.
1999;44:400-6), and Nottingham (BMJ
1997;314:779-82; Gut. 2000;47:804-
11). It has proven to be a fertile area
for research, which is the basis for this
The authors identified 45 studies,
29 in the last decade including a total
of 21,421 participants with exposure
to gastroenteritis. The pooled prevalence for PI-IBS was 11.5% (95%
confidence interval, 8.2%- 15.8%)
but with considerable heterogeneity, which the authors attempted to
explain by a number of subgroup
analyses. The authors report that
protozoal infection seems to have a
higher rate of PI-IBS than bacterial or
viral infection, though some caution
is warranted, since these figures rely
on reports from just one outbreak of
giardiasis in Bergen, Norway (Scand
J Gastroenterol. 2012;47:956-61).
However, if true, this might suggest
that a different immune response
could be responsible, a feature which
others have suggested might predispose particular individuals to PI-IBS
(Gut. 2016;65[ 8]1279-88).
Other notable findings were the
higher incidence of PI-IBS in studies
with low response rates, suggesting
important bias is such studies. Thirty
of the studies included controls to
allow relative risk (RR) estimation.
Pediatric series showed similar RRs to
adults at 4.1 versus 3. 8, respectively.
Age strongly influences immune response and older age was protective
in several studies (Clin Gastroenterol
Hepatol. 2007;5:465-9; J Travel Med.
2014;21:153-8; BMJ. 1997;314:779-
82) but other studies found no effect.
This may relate to an inadequate age
range since the differences were most
marked in those older than 60 years
The meta-analysis confirms the
consistent increased risk in female patients (odds ratio, 1.69), anxiety (OR,
1.97), and somatization (greatest RR,
4.05), all common risks for the development of IBS but not specific to PI-IBS. Initial disease severity indicators,
including bloody stool and more than 7
days of initial illness, which might indicate the severity of underlying damage
to the gut, were shown to be significant
risk factors. Animal studies of acute
infection, particularly parasitic infestation, indicate that significant changes
can be seen in both nerve and muscle,
but routine histology in PI-IBS patients
is normal. Infection produces a striking increase in gut permeability (Gut.
Key clinical point: Infectious enteritis more than quadrupled the
risk of IBS in the subsequent year.
Major finding: A total of 10.1% of
patients with infectious enteritis developed IBS in the next 12 months,
a 4.2-fold increase in risk, compared
with that of controls.
Data source: A systematic review
and meta-analysis of 45 studies.
Disclosures: The National Institutes of Health and the American
funded the work. The investigators
reported having no conflicts of interest.
Infectious enteritis quadrupled short-term risk of IBS
April Gastroenterology (doi: 10.1053/ j.gastro.2016.12.039)