S1518 Why Do IBD Patients Experience Diagnostic Delays? A Tertiary Care Center Study of Patient Journeys Using Large Language Models

Introduction: Timely diagnoses of inflammatory bowel disease (IBD) are necessary to initiate early effective treatment and ensure the best long-term outcomes. However, the root causes of diagnostic delays have remained poorly understood. Given the nuances of diagnosing and treating IBD, patient journeys often involve multiple providers and health systems. We sought to identify the root causes of diagnostic delays and explore potential opportunities for intervention. Methods: We identified 406 adult patients newly diagnosed with IBD after 2012 from our center’s clinical data warehouse. The diagnosis date was operationally defined as the earliest date at which an IBD International Classification of Diseases code was assigned. We compiled all available inpatient, gastroenterology, and primary care de-identified notes dated from 3 years before up to 2 years after the diagnosis. A Health Insurance Portability and Accountability Act-compliant o1 model was utilized to extract the earliest date of symptoms, route of discovery, and the first-ever gastroenterology and non-gastroenterology visit related to features of IBD. Large language model outputs were validated by manual review of a 10-patient random sample, showing 80–100% accuracy. Results: In this cohort, 94% of IBD patients initially presented with a hallmark gastrointestinal symptom, while 6% were incidentally diagnosed. In addition, 69% of the patients initially sought medical evaluation in primary care or non-gastroenterology specialties for IBD symptoms. The greatest delays, affecting more than 20% of the patients, occurred when transitioning from external gastroenterology services (median delay: 233 days) or primary care/non-gastroenterology specialties (median delay: 66 days) to in-system gastroenterology. The median time from an in-system gastroenterology visit to an in-system endoscopy was 38 days. Conclusion: The transition from an external gastroenterology service to a tertiary center accounts for important delays for patients with features of IBD. In addition, facilitating the transition from primary care services to gastroenterology may also be potentially streamlined. Nevertheless, whether these delays stem from scheduling, insurance, uncaptured diagnosis that were reached externally, or other causes needs more granular investigation.