Association Between Proton Pump Inhibitors and Microscopic Colitis.

OBJECTIVE: Microscopic colitis (MC) is a chronic inflammatory disease of the colon that is characterized by chronic, watery, nonbloody diarrhea. Concern regarding a potential association between proton-pump inhibitors (PPIs) and MC has recently emerged. We sought to systematically review and summarize the evidence for the potential association between PPIs and MC. DATA SOURCES: We systematically searched EMBASE, MEDLINE, Cochrane Database of Systematic Reviews, International Pharmaceutical Abstracts, and Google Scholar using the terms proton-pump inhibitors (omeprazole, lansoprazole, dexlansoprazole, rabeprazole, pantoprazole, or esomeprazole), microscopic colitis, collagenous colitis, and lymphocytic colitis. STUDY SELECTION: Full-text, English-language reports of case reports/series, observational studies, experimental studies, and systematic reviews/meta-analyses published between January 2000 to August 2016 were included. Bibliographies from pertinent publications were reviewed for additional references. Outcome was defined as the development of biopsy-confirmed MC. DATA EXTRACTION/SYNTHESIS: A total of 19 publications were identified: 5 case control studies and 14 case reports/series (encompassing a total of 32 cases). All studies were limited by small sample sizes. Risk of MC by dose or specific PPI agent was not investigated in any of the studies. A review of the current body of evidence reveals a possible association between PPIs and MC.
CONCLUSIONS: There is a need for large observational studies of high quality to examine the differential effect of specific PPIs and whether the magnitude of association is dose dependent. Given their widespread use, clinicians should routinely question whether patients are receiving unnecessary treatment with PPIs and discontinue therapy where appropriate.