Phenotypic features and longterm outcomes of pediatric inflammatory bowel disease patients with arthritis and arthralgia

Objective: The natural history of pediatric inflammatory bowel disease (IBD) patients with joint involvement has not been clearly described. Thus, we aimed to investigate phenotypic features and clinical outcomes of this distinct association. Methods: The medical records of patients with pediatric IBD diagnosed from 2000 to 2016 were reviewed retrospectively. Main outcome measures included time to first flare, hospitalization, surgery, and biologic therapy. Results: of 301 patients with Crohn disease (median age 14.2 yrs), 37 (12.3%) had arthritis while 44 (14.6%) had arthralgia at diagnosis. Arthritis and arthralgia were more common in women (p = 0.028). Patients with arthritis and arthralgia demonstrated lower rates of perianal disease (2.7% and 4.5% vs 16.9%, p = 0.013), whereas patients with arthritis were more likely to be treated with biologic therapy (HR 2.05, 95% CI 1.27-3.33, p = 0.009). of 129 patients with ulcerative colitis (UC; median age 13.7 yrs), 3 (2.3%) had arthritis and 16 (12.4%) had arthralgia at diagnosis. Patients with arthralgia were treated more often with corticosteroids (p = 0.03) or immunomodulator therapies (p = 0.003) compared with those without joint involvement. The likelihood to undergo colectomy was significantly higher in patients with arthralgia (HR 2.9, 95% CI 1.1-7.4, p = 0.04). During followup (median 9.0 yrs), 13 patients developed arthritis (3.3%). Arthralgia at diagnosis was a significant predictor for the development of arthritis during followup (HR 9.0, 95% CI 2.86-28.5, p < 0.001). Conclusion: Pediatric IBD patients with arthritis have distinct phenotypic features. Arthralgia at diagnosis is a predictor for colectomy in UC and a risk factor for the development of arthritis during followup.