Drugs that inhibit gastric acid secretion may alter the course of inflammatory bowel disease.
BACKGROUND
Recent data suggest that acid suppressive medications may alter factors central to the pathophysiology of inflammatory bowel diseases (IBD), whether through shifts in the intestinal microbiome due to acid suppression or effects on immune function.


OBJECTIVE
To assess the relationship between the use of proton pump inhibitors (PPIs) or histamine2-receptor antagonists (H2Ra) and incidence of 'flares' (hospitalisation/surgery and change in medication).


METHODS
We conducted a new user cohort study including individuals diagnosed with IBD in British Columbia using linked healthcare utilisation databases (available from July 1996 through April 2006). Propensity-score matched incidence rates during a 6-month follow-up period and rate ratios (RR) and 95% CI were calculated.


RESULTS
Among 16 151 IBD patients, 1307 Crohn's disease (CD) and 996 ulcerative colitis (UC) patients experienced a new use of PPIs, whereas 741 CD and 738 UC used H2Ra. All IBD subgroups were matched separately to an equal number of unexposed IBD patients. H2Ra use in CD doubled the risk of hospitalisation/surgery (RR = 1.94; 95%CI 1.24-3.10) and numerically less so in UC patients (RR = 1.11) with widely overlapping CIs (0.61-2.03). Proton pump inhibitors use was associated with medication change in UC (RR = 1.39; 95%CI 1.20-1.62), but without meaningfully, increased risk of hospitalisation/surgery for UC or CD patients. Extending follow-up showed persistence, but attenuation, of all effects.


CONCLUSIONS
Initiation of PPIs or H2Ra may be associated with short-term changes in the course of IBD. Although confounding by indication was adjusted using propensity score matching, residual confounding may persist and findings need to be interpreted cautiously.
MGH Crohn's & Colitis Center, Department of Gastroenterology & Hepatology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. pjuillerat@partners.org
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Juillerat
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Schneeweiss
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Cook
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Ananthakrishnan
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Mogun
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Korzenik
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001955:British Columbia; D015331:Cohort Studies; D005260:Female; D005744:Gastric Acid / Q000378:metabolism* / Q000502:physiology; D005745:Gastric Acidity Determination; D005750:Gastric Juice / Q000187:drug effects* / Q000502:physiology; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D054328:Proton Pump Inhibitors / Q000494:pharmacology*; D055815:Young Adult
D006635:Histamine H2 Antagonists; D054328:Proton Pump Inhibitors