Intestinal ultrasound as a prognostic tool in new-onset ulcerative colitis—a Copenhagen IBD Cohort Study

Abstract Background and Aims This study assesses the prognostic role of intestinal ultrasound (IUS) in determining the disease course of ulcerative colitis (UC) in the first year after diagnosis. Methods A prospective, multicenter population-based inception cohort study was conducted on patients newly diagnosed with UC. Patients with left-sided or extensive UC underwent IUS assessments at diagnosis, 3 months, and 12 months, alongside symptomatic, biochemical, and endoscopic evaluations. Transmural remission was defined as bowel wall thickness ≤3 mm without color Doppler signal in all segments. Results From May 2021 to April 2023, 193 patients with left-sided or extensive UC were included. Inflammatory findings on IUS at diagnosis were associated with symptomatic, biochemical, and endoscopic markers of inflammation, but not with diagnostic delay. IUS-detected inflammation at diagnosis was an independent predictor for colectomy within the first 3 months, with bowel wall thickness >6 mm as the optimal cutoff (odds ratio 38, 95% confidence interval, 8–270, P < .0001). Three months after diagnosis, 59% of patients achieved transmural remission, which was associated with higher rates of steroid-free clinical remission in all subsequent follow-ups, as well as a reduced need for steroids during follow-up (6% vs. 19%, P = .036). Furthermore, transmural remission at 3 months increased the likelihood of steroid-free clinical remission, as well as transmural and complete remission, at 12 months. Conclusions Findings by IUS at the time of diagnosis predict early colectomy risk in UC. Our results underscore that transmural remission is a feasible treatment target in early UC, and significantly impacts the disease course.