P0316 Systematic assessment of primary sclerosing cholangitis using magnetic resonance cholangiopancreatography in newly diagnosed inflammatory bowel disease – a prospective population-based inception cohort study
Authors: Attauabi M , Roager Madsen G , Møller J , Nielsen Y J W , Bøjer Jensen A , Krieger Jensen F , Siebner H R , Fallentin E , Bendtsen F , Seidelin J B , Burisch J 
Published: January 2025

Abstract

Background
Inflammatory bowel diseases (IBD), encompassing ulcerative colitis (UC) and Crohn’s disease (CD), are associated with increased risk of primary sclerosing cholangitis (PSC). We aimed to determine the occurrence and predictors of PSC in patients with newly diagnosed IBD.

Methods
Since May 1st, 2021, all adult and pediatric patients with incident IBD within a catchment area encompassing 20% of Denmark were enrolled in the prospective population-based Copenhagen IBD Inception Cohort.1 All adult patients were invited for MRCP and blood tests (albumin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, and INR) at IBD diagnosis. PSC-like lesions on MRCPs were evaluated by two experienced radiologists. Multivariate Cox proportional hazard analyses of the disease course of IBD adjusting for age, sex, smoking, and disease phenotype were performed (adjusted HR, aHR, 95% confidence interval).

Results
A total of 527 patients (UC: 326; CD: 201) were included in the cohort, with 242 (74.2%) and 147 (73.1%) undergoing MRCP, respectively, within a median of 2.4 months (interquartile range (IQR) 1.3-4.9) of IBD diagnosis. No clinical differences were observed between patients who underwent MRCP and those who did not.
Definite PSC or PSC-like lesions on MRCP were detected in 33 patients (8.5%), including 17 (7.0%) and 16 (10.9%) with UC and CD, respectively. Of those, 19 patients (4.9%), including 11 (4.5%) with UC and 8 (5.4%) with CD, had definite PSC. No difference was observed in the occurrence of PSC (p=0.37) or PSC-like lesions (p=0.08) in UC vs. CD, nor according to the phenotype of CD; however, PSC lesions in both intra- and extrahepatic bile ducts were more common in UC than in CD (46.2% vs. 6.3%, p=0.02). In addition, a larger proportion with PSC had extensive UC (62.5% vs. 27.1%, p=0.04) or were males (87.5% vs. 44.9%, p=0.03) compared to those without PSC.
During a follow-up of 2.1 years (IQR 1.6-2.6), PSC and PSC-like lesions were both associated with increased risk of intestinal resections (aHR 5.69, 1.13-28.54), biologics (aHR 2.00, 1.04-3.86), hospitalization (aHR 2.70, 1.02-7.12), and systemic steroids (aHR 2.45, 1.02-5.89) in CD but not in UC. None of the PSC cases died, developed cancers, varices, or required liver transplantation within the follow-up period.

Conclusion
In this prospective population-based cohort, we found a considerable proportion (8.5%) to have undetected PSC or PSC-like lesions, despite normal hepatobiliary biochemistry in half of the cases. Both definite PSC and PSC-like lesions had a negative impact on IBD prognosis. The results underscore the importance of systematic screening to mitigate the risk of overlooking PSC.

References
1.Attauabi M, Madsen GR, Bendtsen F, et al. Influence of Genetics, Immunity and the Microbiome on the Prognosis of Inflammatory Bowel Disease (IBD Prognosis Study): the protocol for a Copenhagen IBD Inception Cohort Study. BMJ Open. 2022;12(6):e055779. doi:10.1136/bmjopen-2021-055779