Impact of Diagnostic Delay on Disease Course in Pediatric- versus Adult-Onset Patients with Ulcerative Colitis: Data from the Swiss IBD Cohort.

Given the lack of data, we aimed to assess the impact of the length of diagnostic delay on the natural history of ulcerative colitis (UC) in pediatric (diagnosed <18 years) and adult patients (diagnosed ≥18 years). Data from the Swiss Inflammatory Bowel Disease Cohort Study were analyzed. Diagnostic delay was defined as the interval between the first appearance of UC-related symptoms until diagnosis. Logistic regression modeling evaluated the appearance of the following complications in the long term according to the length of diagnostic delay: colonic dysplasia, colorectal cancer, UC-related hospitalization, colectomy, and extraintestinal manifestations (EIMs). A total of 184 pediatric and 846 adult patients were included. The median diagnostic delay was 4 [IQR 2-7.5] months for the pediatric-onset group and 3 [IQR 2-10] months for the adult-onset group (p = 0.873). In both, pediatric- and adult-onset groups, the length of diagnostic delay at UC diagnosis was not associated with colectomy, UC-related hospitalization, colon dysplasia, and colorectal cancer. EIMs were significantly more prevalent at UC diagnosis in the adult-onset group with long diagnostic delay than in the adult-onset group with short diagnostic delay (p = 0.022). In the long term, the length of diagnostic delay was associated in the adult-onset group with colorectal dysplasia (p = 0.023), EIMs (p < 0.001), and more specifically arthritis/arthralgias (p < 0.001) and ankylosing spondylitis/sacroiliitis (p < 0.001). In the pediatric-onset UC group, the length of diagnostic delay in the long term was associated with arthritis/arthralgias (p = 0.017); however, it was not predictive for colectomy and UC-related hospitalization. As colorectal cancer and EIMs are associated with considerable morbidity and costs, every effort should be made to reduce diagnostic delay in UC patients