The Characteristics and Long-term Outcomes of Pediatric Crohn's Disease Patients with Perianal Disease

Background: Data on the outcomes of children with perianal Crohn's disease are limited. We aimed to assess phenotypic features at diagnosis and long-term disease-specific outcomes of this phenotype. Methods: The medical records of 296 pediatric onset patients with Crohn's disease, diagnosed from 2001 to 2015, were reviewed retrospectively. Baseline characteristics included age, sex, severity indices, laboratory data, endoscopic findings, and anthropometric measurements. Main outcome measures included time to first flare, hospitalization, surgery, and biological therapy. Results: Of the 296 included patients (median age 14.2 years), 70 (24%) had nonfistulizing perianal findings, whereas only 40 (13%) had fistulizing perianal disease at diagnosis. Perianal involvement was associated with female sex (P = 0.01), whereas fistulizing perianal disease resulted in a greater use of immunomodulators (P = 0.01). Time to hospitalization was shorter for both nonfistulizing and fistulizing perianal disease (hazard ratio [HR] 1.66 and 1.34, respectively, P = 0.027) and time to biological therapy (HR 2.1 and 1.7, respectively, P = 0.002). There were no differences in time to first flare or surgery. During a median follow-up of 8.5 years, additional 26 patients (10%) developed fistulizing perianal disease after a median time of 3.5 years. The presence of nonfistulizing disease at diagnosis was a significant risk factor for the development of fistulizing perianal disease (HR 3.4, P = 0.002). At the end of follow-up, complicated disease was more common in patients with any perianal involvement (P = 0.01). Conclusions: Pediatric patients with Crohn's disease with both nonfistulizing and fistulizing disease have worse clinical outcomes. Nonfistulizing disease is a risk factor for the development of fistulizing disease over time.