Supplementary Material for: Clinical utility of intestinal ultrasound for guiding therapy in IBD: A retrospective real-world cohort from a Swiss tertiary center

Background: Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), are chronic immune-mediated disorders that significantly impact patients' quality of life. Proper IBD management often requires invasive diagnostic procedures such as endoscopy. Transabdominal intestinal ultrasound (IUS) offers a promising alternative due to its non-invasive, inexpensive, and widely available nature. This study aims to evaluate the effectiveness of IUS combined with clinical parameters in guiding treatment decisions for IBD patients in remission or relapse.
Methods: Retrospective cohort study of University Hospital Zurich (January-August 2022), which included consecutive adult IBD patients undergoing a single transabdominal IUS for treatment decision-making. IUS influenced clinical decisions by guiding therapy continuation, modification, or cessation and addressing complications.
Results: The study analyzed 103 consecutive IBD patients, 66% diagnosed with CD and 34% with UC. The majority (69.9%) were in clinical remission, and two-third of the remission patients claimed also no symptoms. (32% of the whole cohort were asymptomatic). Bowel wall thickness (BWT) in the terminal ileum and left colon also significantly influenced treatment decisions (p = 0.014 and p = 0.042, respectively). In a multivariable logistic regression, both diarrhea (p = 0.013) and maximal BWT (p = 0.020) remained statistically significant predictors for a change in treatment.
Conclusion: The study demonstrates that IUS, along with clinical symptoms such as diarrhea, plays a significant role in guiding treatment decisions for IBD patients. Diarrhea and BWT were strong predictors for adjusting therapy, highlighting the value of integrating non-invasive imaging with clinical assessment to optimize IBD management.