Background: The implication of microscopic ileitis finding in patients referred for ileocolonoscopy for clinically suspected inflammatory bowel disease is not well defined and its correlation with clinical outcome has not been fully studied. The current study aims to determine the prognostic yield of biopsies in this setting, and to evaluate the correlation of microscopic ileitis with long-term clinical outcome.
Methods: Endoscopic reports of patients referred to our department for ileocolonoscopy in the years 2010-2016, as part of a diagnostic work-up for suspected IBD were revised. Patients with normal ileocolonoscopy were included, provided that terminal ileum biopsies were performed. Accordingly, patients were divided into normal (normal or reactive changes) and microscopic ileitis (inflammation or ileitis of any severity) groups. Both groups were followed prospectively to determine clinical outcome.
Results: 439 patients met the inclusion criteria. 64 (14.6%) had inflammation on biopsy and were included in the microscopic ileitis group. Age and gender didn't differ significantly between groups. Overall follow up period was 6.1±2.3 years. Patients in the microscopic ileitis group were significantly associated with Crohn's diagnosis during follow-up period compared to normal (19% vs 2%, OR=11.98, 95%CI=4.48-32.01; p<0.01). Patients with granuloma or moderate-severe ileitis on biopsy were significantly associated with Crohn's development (100% vs 11%; P<0.01) compared to mild or nonspecific inflammation.
Conclusion: Microscopic ileitis finding in clinically suspected IBD is associated with increased risk of future diagnosis of crohn's disease.