Risk Factors for Disease Behavior Evolution and Efficacy of Biologics in Reducing Progression in Pediatric Patients with Nonstricturing, Nonpenetrating Crohn's Disease at Diagnosis: A Single-Center Experience in Korea.

Background/Aims: : Recently, the treatment of Crohn's disease (CD) has changed to a treat-to-target strategy, in which disease progression is prevented with early intervention. We analyzed the long-term evolution of nonstricturing, nonpenetrating (B1) disease at diagnosis and factors related to disease evolution in pediatric CD. Methods: We retrospectively analyzed 402 patients between 2000 and 2013 who were younger than 18 years and had B1 disease at CD diagnosis. The median follow-up was 6.1 years (range, 1 to 13 years). The cumulative probabilities of developing stricturing (B2) or penetrating (B3) disease and associations between risk factors and disease behavior evolution were evaluated. Results: Among the 402 patients, 75 (18.7%) had B2 or B3 disease by the final follow-up. The cumulative probabilities of disease behavior evolution were 18.3%, 34.3%, and 50.9% at 5, 10, and 13 years, respectively. Patients whose disease progressed had an increased risk of intestinal resection (hazard ratio [HR], 3.61; 95% confidence interval [CI], 2.25 to 6.03; p<0.001). First-degree family history of inflammatory bowel disease (HR, 2.38; 95% CI, 1.07 to 5.28; p=0.032), isolated ileal involvement at diagnosis (HR, 7.55; 95% CI, 1.04 to 15.57; p=0.045), and positive anti-Saccharomyces cerevisiae antibody titers (HR, 2.10; 95% CI, 1.03 to 4.25; p=0.040) were associated with disease behavior evolution. Early treatment with biologics significantly reduced disease progression (HR, 0.46; 95% CI, 0.79 to 3.39; p=0.042). Conclusions: This study suggests that early aggressive therapy should be considered in B1 behavior pediatric CD patients with risk factors of disease evolution to improve long-term outcomes.