Proton pump Inhibitors and Risk of Enteric Infection in Inflammatory Bowel Disease: A Self-controlled Case Series

Lay Summary We tested whether proton pump inhibitors (PPIs) are associated with enteric infections among those with inflammatory bowel disease (IBD) by using a case-controlled series method, which allows for controlling of residual confounding. We studied ambulatory IBD patients who were tested for enteric infection from 2015 to 2019 and received PPIs for some of this period. Rates of enteric infections were compared between the PPI exposed period vs pre- and post-PPI periods identical in duration to the exposed period. We found that PPIs were associated with a 3-fold increased risk for enteric infection among those with IBD but had a modest absolute risk. Background We tested whether proton pump inhibitors (PPIs) are associated with enteric infections among those with inflammatory bowel disease (IBD), after adequately accounting for baseline differences between PPI users and nonusers. Methods This was a self-controlled case series, with each patient serving as their own control. Ambulatory patients with IBD were included if they were tested for enteric infection by multiplex polymerase chain reaction testing panel (GIPCR) and/or Clostridoides difficile toxin PCR from 2015 to 2019 and received PPIs for some but not all of this period. Rates of enteric infections were compared between the PPI-exposed period vs pre- and post-PPI periods identical in duration to the exposed period. Conditional Poisson regression was used to adjust for time-varying factors. Results Two hundred twenty-one IBD patients were included (49% ulcerative colitis, 46% Crohn's disease, and 5% indeterminate colitis). The median PPI duration was 7 months (interquartile range 4 to 11 months). A total of 25 (11%) patients had a positive GIPCR or C. difficile test in the PPI period, 9 (4%) in the pre-PPI period, and 8 (4%) in the post-PPI period. Observed incidence rates for enteric infections were 2.5, 7.4, and 2.2 per 100 person years for the pre-PPI, PPI, and post-PPI periods, respectively (adjusted incidence rate ratios, 2.8; 95% confidence interval [CI] 1.3-6.0) for PPI vs pre-PPI and 2.9 (95% CI, 1.3-6.4) for PPI vs post-PPI). The adjusted absolute excess risk associated with PPIs was 4.9 infections per 100 person years. Conclusions Proton pump inhibitors were associated with a 3-fold increased risk for enteric infection among those with IBD but had a modest absolute risk.