Inflammatory Bowel Disease in Children with Systemic Juvenile Idiopathic Arthritis

Objective: The incidence of inflammatory bowel disease (IBD) in juvenile idiopathic arthritis (JIA) is higher than in the general pediatric population. However, reports of IBD in the systemic JIA (sJIA) subtype are limited. We sought to characterize sJIA patients diagnosed with IBD and to identify potential contributing risk factors.

Methods: Using an internationally distributed survey, we identified 16 sJIA patients who were subsequently diagnosed with IBD (sJIA-IBD cohort). 522 sJIA patients without IBD were identified from the CARRA Legacy Registry and served as the sJIA-only cohort for comparison. Differences in demographic, clinical characteristics and therapy were assessed using chi-square test, Fisher's exact test, t-test, and univariate and multivariate logistic regression as appropriate.

Results: 75% of sJIA-IBD patients had a persistent sJIA course; 25% had a history of MAS. sJIAIBD subjects were older at sJIA diagnosis, more often non-White, had a higher rate of IBD family history, and were more frequently treated with etanercept or canakinumab compared to sJIA-only subjects. 69% of sJIA-IBD patients successfully discontinued sJIA medications following IBD diagnosis, and sJIA symptoms resolved in 9/12 patients treated with TNF-α inhibitors.

Conclusion: IBD in the setting of sJIA is a rare occurrence. The favorable response of sJIA symptoms to therapeutic TNF-α inhibition suggests that the sJIA-IBD cohort may represent a mechanistically distinct sJIA subgroup. Our study highlights the importance of maintaining a high level of suspicion for IBD when gastrointestinal involvement occurs in sJIA patients and the likely broad benefit of TNF-α inhibition in those cases.