Validation of the simplified PIBD-classes criteria: A single-center retrospective study.

Background: Pediatric inflammatory bowel disease (PIBD) subtypes are classified according to the PIBD-classes criteria, comprising 23 items. These criteria were later simplified to 19 diagnostic items. Inflammatory bowel diseases (IBDs) are classified as ulcerative colitis (UC), atypical UC, IBD-unclassified (IBD-U), Crohn's disease (CD), or isolated colonic CD. This study aimed to validate the simplified PIBD-classes criteria in an Asian population and evaluate IBD-U characteristics.

Methods: Patients diagnosed with PIBD between 2007 and 2022 were retrospectively enrolled. Data regarding PIBD phenotypes, age at diagnosis, endoscopic and pathological findings, and biologics and/or steroid use were collected from medical records. Physician-assigned diagnoses were compared with simplified PIBD-classes criteria-based diagnoses. Differences in the clinical features of patients with IBD-U and other IBDs classified using the simplified PIBD-class criteria were also evaluated.

Results: Eighty-six patients were included, of whom 54 (63%) had UC, 21 (24%) had CD, and 11 (13%) had IBD-U. Using the simplified PIBD-classes criteria, 48 (56%) patients were diagnosed with UC, 3 (3%) with atypical UC, 22 (26%) with CD, 1 (1%) with isolated colonic CD, and 12 (14%) with IBD-U. The diagnoses were changed in 10 cases based on the simplified PIBD-classes criteria. There were no significant differences in age at diagnosis or rates of steroid and biologic use between IBD subtypes.

Conclusions: Simplified PIBD-classes criteria-based diagnoses matched physician-assigned diagnoses in almost all cases. This study suggests that the simplified PIBD-classes criteria are useful at reducing diagnostic variability in multicenter and international PIBD studies.