LAUSR

Objectives: Data on the phenotypes and disease outcomes of very early-onset inflammatory bowel disease (VEO-IBD) are limited. The aims of this study were to describe the clinical features, outcomes, and treatment response of VEO-IBD patients and to compare them with later-onset pediatric inflammatory bowel disease (P-IBD) patients. Methods: All consecutive patients aged 0–6 years who were diagnosed with Crohn disease (CD), ulcerative colitis, or IBD unclassified (IBD-U) at 2 academic hospitals from 2010 to March 2021 were included. They were compared to sex-matched IBD patients aged 6–17 years. Results: Two hundred thirty-two patients were included, 78 (34%) with VEO-IBD and 154 (66%) with P-IBD. IBD-U was the most common diagnosis in the VEO-IBD group compared to P-IBD (28% vs 3%, P < 0.001), while CD was predominant in older children (27% vs 52%, P < 0.001). The VEO-IBD group showed lower rates of clinical remission after induction with steroids compared to older children (82% vs 93%, P = 0.01), higher rates of steroid resistance (14% vs 5%, P = 0.02), and steroid dependence (27% vs 8%, P < 0.001). The number of patients who started anti-tumor necrosis factor (TNF)-α agents was similar between the groups. Anti-TNF-α retention was lower in the VEO-IBD group at 1 and 2 years (59% vs 85%, P = 0.003; 16% vs 55%, P < 0.001, respectively). Surgical risk appeared to be higher for VEO-IBD (32% vs 14%, P < 0.001). Conclusions: When compared to P-IBD patients, patients with VEO-IBD may have a more severe disease course, a poorer response to steroids and anti-TNF-α agents, and require more frequent surgical procedures.