Psoriasis Patients are Associated with Increased Risk of New-Onset Irritable Bowel Syndrome: A Multicenter, Retrospective Cohort Study

Background: Psoriasis is a chronic systemic inflammatory disease linked to multiple comorbidities. The association between psoriasis and irritable bowel syndrome (IBS) remains insufficiently characterized. Methods: We conducted a retrospective cohort study using the TriNetX US Collaborative Network. Adults with psoriasis (ICD-10-CM L40) diagnosed between 2005 and 2023 were matched 1:1 with non-psoriasis controls based on demographics, socioeconomic status, comorbidities, and healthcare utilization. IBS (ICD-10-CM K58) diagnoses within 90 days of index were excluded. Cox regression models estimated hazard ratios (HRs) with 95% confidence intervals (CIs). Sensitivity analyses varied wash-out periods, follow-up durations, and exposure definitions. Results: After matching (n=256,550 per group), people with psoriasis were associated with a higher risk of IBS (HR 1.244, 95% CI 1.168-1.325) in the 15-year follow-up model while comparing with non-psoriasis controls. Subgroup analyses validated elevated risks among both age groups (e.g., age ≥65 years: HR 1.325, 95% CI 1.167-1.505) and sexes (female: HR 1.291, 95% CI 1.197-1.393). All sensitivity models yielded consistent results. Conclusion: Psoriasis is independently associated with an increased risk of subsequent IBS. Routine gastrointestinal symptom screening in psoriasis patients may improve comprehensive care.