Antibiotic Use During GI Infection Linked to Higher IBS Risk

Key Takeaways

• Pooled estimates suggested higher IBS incidence among patients who received antibiotics than among those who did not, with very high heterogeneity across studies.
• In analyses limited to gastrointestinal infections, the pooled IRR was 1.71 (95% CI, 1.16–2.51; P=.007).
• Investigators reported substantial heterogeneity and noted limitations across included studies.

The analysis focused on new IBS diagnoses after excluding prior IBS. Across 31 studies involving 422,350 patients, the pooled IBS incidence was 26% (95% CI, 18%–35%) among antibiotic-exposed patients and 20% (95% CI, 11%–30%) among those without antibiotic exposure, with very high heterogeneity (I² > 90%) in both groups. Investigators presented this as an association rather than evidence that antibiotics directly caused subsequent IBS, and they reported substantial variation across included studies.

This systematic review and meta-analysis pooled comparative and single-arm evidence to examine new IBS diagnoses after antibiotic use, excluding studies in which IBS was already present. Overall, the pooled incidence rate ratio (IRR) per 1000 person-years was 1.3 (95% CI, 1.07–1.58; P=.008) for antibiotic users versus nonusers, with high heterogeneity (I² > 90%). Follow-up periods ranged from several months to many years, allowing assessment of IBS diagnosed after the infectious episode. The report presented both absolute incidence estimates and a relative comparison, rather than relying on a single summary measure.

Subgroup and sensitivity analyses suggested that the association differed by infection setting rather than appearing consistently across all antibiotic exposures. In analyses limited to gastrointestinal infections, the pooled comparison was stronger than the overall estimate, helping separate enteric infection–related exposure from antibiotics given for unrelated infections. Investigators described the association as most pronounced in the enteric infection setting.

High heterogeneity was reported across analyses, affecting both pooled incidence estimates and comparative measures of IBS occurrence. Meta-regression identified geographic area, the criteria used to diagnose IBS, and study quality as contributors to variability, though differences persisted across study designs and regions. Many included studies were retrospective, and several potentially important confounders were not reported, including diet, genetic susceptibility, psychological comorbidities, concurrent diseases with intestinal somatization, and other medications. Investigators also noted that patients who received antibiotics may have had more severe gastrointestinal infections than those who did not, and they emphasized the observational nature of the findings.