# Impact of Biologics and Proton Pump Inhibitors on Gastrointestinal Infection Risk in Inflammatory Bowel Disease Patients: A Retrospective Analysis of Pathogen-Specific Outcomes and Treatment Interactions

## TL;DR

This study finds that biologic drugs significantly increase the risk of gastrointestinal infections in IBD patients, more than proton pump inhibitors or no treatment.

## Contribution

The study provides new insights into the specific impact of biologics and PPIs on non-C.diff GI infections in IBD patients.

## Key findings

- Biologic therapy alone or with PPIs significantly increases GI infection risk compared to untreated patients.
- Non-C.diff infections are strongly associated with biologic use, particularly vedolizumab and adalimumab.
- PPIs alone slightly increase GI infection risk, but bacterial pathogens like E. coli and Salmonella are common across treatment groups.

## Abstract

Background/Objectives: Inflammatory bowel disease (IBD) patients face elevated gastrointestinal (GI) infection risks due to immune dysregulation and gut dysbiosis. While steroids and immunosuppressants are known to increase infection risk, data on biologics and proton pump inhibitors (PPIs) remain limited, particularly for non-Clostridioides difficile (C.diff) infections. Methods: This retrospective cohort study analyzed 9849 hospitalized IBD patients (2013–2023) from the Northwell Inpatient Database. Patients were categorized into four groups: biologics-only, PPIs-only, both, or neither. GI infections were identified via C.diff PCR, GI PCR, and chart review. Multivariate logistic regression adjusted for demographics, BMI, and IBD type. Results: GI infections occurred in 1.75% of patients, with significantly higher odds in those on biologics alone (OR 21.5, 95% CI 11.7–39.4) or with PPIs (OR 16.6, 95% CI 10.2–26.8) versus untreated patients. Non-C.diff infections were strongly associated with biologics (OR 20.7, 95% CI 10.2–41.9). PPIs alone increased slightly the risk of GI infections (OR 1.6, 95% CI 1.1–2.4). Vedolizumab and adalimumab had the highest infection risks among biologics (26.8% and 22.7%, respectively). Bacterial pathogens, such as E. coli and Salmonella, predominated, with no significant difference in causative agents across treatment groups. Conclusions: Biologic therapy greatly increases GI infection risk in IBD patients independent of PPI use. Clinicians should weigh infection risks when prescribing biologics, particularly in high-risk populations. Further studies are needed to assess risks by biologic subtype and the interplay with PPIs.