Predictors of Complicated Disease Course in Children and Adults With Ulcerative Colitis: A Nationwide Study From the epi-IIRN

Background: Data on predictors of complicated ulcerative colitis (UC) course from unselected populations cohorts are scarce. We aimed to utilize a nationwide cohort to explore predictors at diagnosis of disease course in children and adults with UC. Methods: Data of patients diagnosed with UC since 2005 were retrieved from the nationwide epi-IIRN cohort. Complicated disease course was defined as colectomy, steroid-dependency, or the need for biologic drugs. Hierarchical clustering categorized disease severity at diagnosis based on complete blood count, albumin, C-reactive protein and erythrocyte sedimentation rate (ESR), analyzed together. Results: A total of 13 471 patients with UC (1427 [11%] pediatric-onset) including 103 212 person-years of follow-up were included. Complicated disease course was recorded in 2829 (21%) patients: 1052 (7.9%) escalated to biologics, 1357 (10%) experienced steroid-dependency, and 420 (3.1%) underwent colectomy. Probabilities of complicated disease course at 1 and 5 years from diagnosis were higher in pediatric-onset (11% and 32%, respectively) than adult-onset disease (4% and 16%; P < .001). In a Cox multivariate model, complicated course was predicted by induction therapy with steroids (hazard ratio [HR], 1.5; 95% CI, 1.2-2.0), extraintestinal manifestations (HR, 1.3; 95% CI, 1.03-1.5) and the disease severity clusters of blood tests (HR, 1.8; 95% CI, 1.01-3.1), while induction therapy with enemas (HR, 0.6; 95% CI, 0.5-0.7) and older age (HR, 0.99; 95% CI, 0.98-0.99) were associated with noncomplicated course. Conclusion: In this nationwide cohort, the probability of complicated disease course during the first 5 years from diagnosis was 32% in pediatric-onset and 16% in adults with UC and was associated with more severe clusters of routinely collected laboratory tests, younger age at diagnosis, extraintestinal manifestations, and type of induction therapy.