P0472 Impact of diagnostic delay on disease progression and advanced treatment requirements in a real-world Inflammatory Bowel Disease cohort

Abstract Background The diagnostic delay, representing the symptom-to-diagnosis interval, is a modifiable quality metric, yet its independent impact on long-term disease progression and treatment burden, particularly across Crohn’s Disease (CD) and Ulcerative Colitis (UC) phenotypes, remains insufficiently defined in real-world settings. Methods This was a retrospective cohort study of 913 Inflammatory Bowel Disease (IBD) patients (CD: 49.7%, UC: 50.3%) followed at a single tertiary center between 2000 and 2024. Patients were categorized by clinically relevant diagnostic delay thresholds. Primary endpoints included the need for abdominal surgery, risk of multiple hospitalizations, and time to biologic therapy initiation. Multivariate Binary Logistic Regression was used to calculate Adjusted Odds Ratios (aORs), and Cox Proportional Hazards Regression determined Hazard Ratios (HRs), with models robustly adjusted for critical confounders including age at diagnosis, sex, Montreal classification, and baseline disease activity. Results The median diagnostic delay was significantly longer in CD (6 months, IQR: 1–24) than in UC (3 months, IQR: 1–9) (P = 0.021). A prolonged diagnostic delay (greater than 18 months) was confirmed as an independent risk factor for surgery (aOR = 9.85, 95% CI: 6.41-15.12, P < 0.001). This risk was dramatically elevated in the CD cohort, demonstrating a nearly thirteenfold increased odds (aOR = 12.5, 95% CI: 7.5-20.8, P < 0.001). A diagnostic delay greater than 3 months was an independent predictor of recurrent hospitalization (aOR = 4.62, 95% CI: 3.42-6.23, P < 0.001), with Cox regression showing a faster time to first hospitalization (HR = 2.3, 95% CI: 1.78-2.96, P < 0.001). Furthermore, the Incidence Rate of hospitalizations in the long diagnostic delay group was 15.2 events per 100 patient-years compared to 8.5 events per 100 patient-years in the short diagnostic delay group. Finally, a diagnostic delay exceeding 12 months was an independent predictor for the need for biologic therapy (aOR = 5.75, 95% CI: 4.17-7.94, P < 0.01) and predicted a faster time to initiation (HR = 2.97, 95% CI: 2.24-3.94, P < 0.01). Conclusion A prolonged diagnostic delay is an independent, powerful, and potentially modifiable risk factor for adverse disease progression, high healthcare utilization, and increased advanced treatment requirements in IBD. This effect is particularly pronounced in Crohn’s Disease. These findings underscore the critical importance of implementing rapid diagnostic pathways to mitigate long-term morbidity. Conflict of interest: Dr. Telli, Pelin: No conflict of interest Dağcı, Gizem: No conflict of interest Yağlı, Mehmet Akif: no conflicts of interest Gurbanov, Asım: No conflict of interest Agargun, Besim Fazil: No conflict of interest Mammadov, Sabuhi: No conflict of interest Bilgin, Ersel: No conflict of interest Genc Ulucecen, Sezen: No conflict of interest Cavus, Bilger: No conflict of interest Ormeci Çifcibaşi, Asli: No conflict of interest Demir, Kadir: No conflict of interest Besisik, Fatih: No conflict of interest Kaymakoglu, Sabahattin: No conflict of interest Akyüz, Filiz: No conflict of interest