The value of intestinal ultrasound scores in predicting long-term endoscopic outcomes in ulcerative colitis.

Background: The value of intestinal ultrasound (IUS) in predicting treatment outcomes in ulcerative colitis (UC) remains underexplored.

Objectives: To compare the predictive accuracy of representative IUS scores for long-term endoscopic outcomes in UC.

Design: A retrospective observational study.

Methods: Consecutive UC patients initiating biologics/small-molecule drugs were enrolled. IUS examinations were performed at baseline, 4-6 months, and at the first colonoscopy reassessment (12-30 months). IUS images were reviewed, and bowel wall thickness (BWT), Milan ultrasound criteria (MUC), and International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) were recorded. Endoscopic response was assessed using the Mayo Endoscopic Score (MES), with remission defined as MES = 0 and improvement as MES ⩽1.

Results: Forty-nine patients were included. All three IUS scores showed significant correlations with concurrent MES, with IBUS-SAS demonstrating the strongest association (BWT, ρ = 0.54; MUC, ρ = 0.55; IBUS-SAS, ρ = 0.69). IBUS-SAS at 4-6 months was the most accurate predictor of long-term endoscopic remission (area under the curve (AUC) 0.767) and endoscopic improvement (AUC 0.770). On multivariable analysis, an IBUS-SAS score <25.5 at 4-6 months was the only independent predictor of endoscopic remission (odds ratio (OR) 7.6, p = 0.005), while an IBUS-SAS score <38.0 was the only independent predictor of endoscopic improvement (OR 5.8, p = 0.006).

Conclusion: The IBUS-SAS score at early follow-up may serve as a valuable predictor of long-term endoscopic outcomes in UC.