Early intestinal ultrasound in severe ulcerative colitis identifies patients at increased risk of 1-year treatment failure and colectomy.

Background and aims: Reliable and easily accessible objective markers of disease activity to predict long-term treatment outcomes in severe ulcerative colitis (UC) are missing. We aimed to investigate if intestinal ultrasound (IUS) might predict long-term outcomes in hospitalized patients with severe UC treated with intravenous corticosteroids.

Methods: Hospitalized patients with severe UC and IUS inflammation (bowel wall thickness (BWT)>3.0mm) starting IV corticosteroids were recruited at three university hospitals in Denmark. IUS was performed before treatment, 48±24 hours (h), 6±1 days, and 3 months after treatment initiation. Time until colectomy or need for new interventions was registered together with Mayo score at 3 months and partial Mayo score (pMayo) at 12-months. Follow-up time was 12 months.

Results: Fifty-six patients were included in the final analysis. Forty-five (80%) patients needed intervention, including 9 colectomies, during the 12-month follow-up. After 48±24h: No patient with a BWT<3mm needed a colectomy, p=0.04. BWT≥4mm showed an increased risk of colectomy (odds ratio 9.5 (95%CI 1.5-186), p=0.03), while a BWT≥3mm showed an increased risk of intervention (3.6 (1.1-12.5), p=0.03). A BWT≥4mm resulted in a significantly shorter time until both colectomy, p=0.03, and treatment intensification (mean days 75 (95%CI24-127) vs. 176 (119-233), p=0.005. However, neither IUS parameters nor pMayo score, CRP, hemoglobin, or p-albumin could predict remission at 3- and 12-months.

Conclusion: BWT assessed at 48h post intravenous corticosteroid initiation in patients hospitalized with severe UC may identify patients with an increased risk of short- and long-term colectomy and predict a more aggressive short-term disease course.