Perianal Crohn Disease in a Large Multicenter Pediatric Collaborative.

Background: Although perianal complications of Crohn disease (CD) are commonly encountered in clinical practice, the epidemiology of perianal CD among populations of children is poorly understood. We sought to characterize the prevalence of perianal disease in a large and diverse population of pediatric patients with CD.

Methods: We conducted retrospective analyses from a prospective observational cohort, the ImproveCareNow Network (May 2006-October 2014), a multicenter pediatric inflammatory bowel disease quality improvement collaborative. Clinicians prospectively documented physical examination and phenotype classification at outpatient visits. Perianal examination findings and concomitant phenotype change were used to corroborate time of new-onset perianal disease. Results were stratified by age, sex, and race and compared across groups with logistic regression. Cumulative incidence was estimated using Kaplan-Meier analyses and compared between groups with Cox proportional hazard regression models.

Results: The registry included 7076 patients with CD (41% girls). Missing/conflicting entries resulted in 397 (6%) patient exclusions. Among the remaining 6679 cases, 1399 (21%) developed perianal disease. Perianal disease was more common among boys (22%) than girls (20%; P = 0.013) and developed sooner after diagnosis among those with later rather than early onset disease (P < 0.001). Perianal disease was also more common among blacks (26%) compared with whites (20%; P = 0.017). Asians with later onset CD developed perianal disease earlier in their disease course (P = 0.01). There was no association between disease location or nutritional status at diagnosis and later development of perianal disease.

Conclusions: In this large multicenter collaborative, we found that perianal disease is more common among children with CD than previously recognized. Differences in the development of perianal disease were found across racial and other subgroups. Treatment strategies are needed to prevent perianal disease development.