Implementation of intestinal ultrasound and optimal use of biologics in inflammatory bowel disease

Part I of this thesis focuses on optimal implementation of intestinal ultrasound (IUS) for inflammatory bowel disease (IBD) patients. Firstly, we reviewed existing IUS scoring indices for grading of disease severity and concluded that the existing indices were developed with suboptimal methodology. Subsequently, we developed a novel IUS index for grading of disease severity in ulcerative colitis patients, using colonoscopy as the reference standard. We also studied point-of-care (POC) implementation of IUS at our clinic and developed a POC IUS algorithm based on our findings. Finally, we studied contrast enhanced ultrasound (CEUS) and conventional ultrasound for treatment follow-up in Crohn’s disease patients. We concluded that CEUS is of little added value and that bowel wall thickness and colour Doppler signal are the most useful parameters for this purpose. Part II of this thesis includes several studies on biologic treatment in IBD patients. We reviewed anti-drug antibody (ADA) formation against all available biologics for treatment of IBD and concluded that combination treatment with immunomodulators reduces ADA formation in most agents. Furthermore, we studied patterns of anti-TNF use in the Netherlands, showing the increasing use of these agents. Finally, we studied relapse rates in IBD patients that discontinued anti-TNF treatment while in remission. Although a significant proportion of patients had a relapse, we concluded that anti-TNF agents can be safely and effectively reintroduced in more than 80% of patients.