P0354The Effect of Diagnostic Delay on the Disease Course of Ulcerative Colitis and Crohn’s Disease

Background Ulcerative colitis (UC) and Crohn’s disease (CD) are chronic relapsing conditions characterized by intestinal inflammation, and early treatment is vital to control symptoms. Diagnostic delay (DD) contributes to adverse outcomes and increased disease burden. This study aimed to determine the median DD and evaluate its impact on the clinical course, surgical intervention, and disease course. Methods This retrospective study included patients were followed between March 2019 and October 2025. The data were derived from the patient records. DD was defined as the interval between the first inflammatory bowel disease (IBD) symptom prompting medical consultation and the date of definitive diagnosis. For analysis, patients were classified by a 3-month cut-off. This 3-month threshold, based on our cohort’s data distribution, was used to assess the impact of early delay. Results A total of 1854 IBD patients (891 CD, 48.1%; 963 UC, 51.9%) were included. The median DD was 2.9 months in the entire study group; it was significantly longer in CD patients than in UC patients (6.1 months and 1.1 months, p < 0.001). In the CD patients, ileal involvement was significantly more common in the prolonged group compared to the early group (52.0% vs. 39.1%, p < 0.001). The most notable finding was that progression to a stenosing phenotype at last follow-up was statistically significantly higher in the prolonged group compared to the early group (12.6% vs. 5.8%, p = 0.006). Conversely, the need for emergency surgery was significantly higher in the early CD group (54.9% vs. 38.2%, p = 0.003). UC patients with prolonged DD had a significantly higher median baseline partial Mayo score (4 vs. 0, p = 0.017). Furthermore, our study revealed that biologic-naive status was more likely to occur in the prolonged group (69.8% vs. 63.2%, p = 0.039) signifying that biologic agent utilization was more prevalent in the early group. No significant difference in surgical rates was observed. Conclusion In our study, DD was significantly longer in CD patients than in UC patients and was associated with progression to stenosing phenotype and ileal involvement in CD. Moreover, in UC patients, the baseline partial Mayo score considerably increased in the prolonged delay group. Conflict of interest: Dr. Ozturk, Oguz: No conflict of interest Ergul, Mucahit: No conflict of interest Keskin, Emir Tugrul: No conflict of interest Acun, Kadir Can: No conflict of interest Yilmaz, Eren: No conflict of interest Cagir, Yavuz: No conflict of interest Atay, Ali: No conflict of interest Coskun, Orhan: No conflict of interest Yuksel, Ilhami: No conflict of interest