Long-term Outcome of Inflammatory Bowel Disease-Unclassified in Children.

Objective: To document the frequency at diagnosis and evolution over time of inflammatory bowel disease-unclassified in children.

Methods: Analysis of case records (2004-2011) of patients diagnosed with inflammatory bowel disease-unclassified following upper-gastrointestinal endoscopy, ileocolonoscopy and small bowel imaging. Any subsequent diagnostic reclassification by 2016 was recorded.

Results: 344 children diagnosed as inflammatory bowel disease: 58% Crohn's disease, 34.5% ulcerative colitis, and 7.5% (n=26) inflammatory bowel disease-unclassified. 25/26 inflammatory bowel disease-unclassified patients were followed for 4.5-11.5 years. 17 of these patients needed endoscopic re-evaluation leading to changed diagnosis in ten (Crohn's disease 7, ulcerative colitis 3).

Conclusions: 7.5% (25/344) of inflammatory bowel disease children had inflammatory bowel disease-unclassified at diagnosis; 10 (40%) evolved into Crohn's disease or ulcerative colitis.