Clinical Outcome Assessments in Pediatric Patients With Ulcerative Colitis and Crohn's Disease Receiving Biologics: A Retrospective Cohort Study.

Background: To assess disease activity, steroid-free remission, and other clinical outcome assessments among pediatric patients with ulcerative colitis (UC) and Crohn's disease (CD) in the ImproveCareNow (ICN) registry. Methods: Patients aged 2-17 years diagnosed with UC or CD between June 1, 2013 and December 31, 2019 were enrolled if they initiated a biologic after enrollment in the ICN registry and completed at least 12 months follow-up after first maintenance dose. Baseline (at biologic initiation) demographics were summarized using descriptive statistics. Pediatric UC Activity Index (PUCAI), partial Mayo score, and Physician Global Assessment (PGA) were assessed for UC; and the Short Pediatric Crohn's Disease Activity Index (sPCDAI) and PGA were assessed for CD at first maintenance dose, 1- and 3-year time points. Kappa coefficients were used to assess the level of agreement between the outcome measures. Results: A total of 1887 patients (UC = 350; CD = 1537) were included. Baseline demographics were similar across groups. For UC patients, mean PUCAI scores decreased and the proportion of patients in steroid-free remission, quiescent state based on PGA, and remission based on partial Mayo score increased from first maintenance dose to 1 and 3 years. For CD patients, mean sPCDAI score of CD patients decreased and the proportion of patients in steroid-free remission by sPCDAI and in quiescent state based on PGA increased from first maintenance dose to 1 and 3 years. Kappa coefficients showed only modest correlation between disease activity assessments. Conclusions: Disease activity scores improved over time, with more pediatric patients with UC and CD achieving steroid-free remission at 1 and 3 years after first biologic maintenance dose.