Risk for Post-Colonoscopy Irritable Bowel Syndrome in Patients With and Without Antibiotic Exposure: A Retrospective Cohort Study

Background & Aims: Laboratory studies have demonstrated that antibiotic use in conjunction with bowel purgatives causes alterations to the gut microbiota. Because gut microbiota changes may be a trigger for the development of irritable bowel syndrome (IBS), we sought to assess whether individuals who undergo bowel cleansing for colonoscopy and have concurrent antibiotic exposure develop IBS at higher rates than individuals who undergo colonoscopy without antibiotic exposure. Methods: We used data from Optum's de-identified Clinformatics Data Mart Database in the United States to study a cohort of 50- to 55-year-olds who underwent screening colonoscopy. Individuals exposed to antibiotics within 14 days of colonoscopy were propensity-score matched to individuals who were not exposed to antibiotics around colonoscopy. The primary outcome was a new IBS diagnosis, and the composite outcome was a new claim for IBS, IBS medications, or IBS symptoms. The association of antibiotic exposure and the outcomes was calculated using Cox proportional hazards regression. Results: There were 408,714 individuals who met criteria for the screening colonoscopy cohort. Of these, 24,617 (6.0%) were exposed to antibiotics around the time of colonoscopy, and they were propensity-score matched to 24,617 individuals not exposed to antibiotics. There was no statistically significant association between antibiotic use and IBS (hazard ratio, 1.11; 95% confidence interval, 0.89–1.39), but there was a weak association between antibiotic use and the composite outcome (hazard ratio, 1.12; 95% confidence interval, 1.02–1.24; number needed to harm, 94). Conclusions: Individuals concurrently exposed to antibiotics and bowel purgative had slightly higher rates of surrogate IBS outcomes compared with matched controls who did not receive antibiotics concurrently with bowel purgative.