Maarten Cozijnsen

148 • Both government and healthcare payers are more inclined to contribute financially to registries if all hospitals in the nation participate in the registry. Scientific associations, such as pediatric IBD working group (KICC) of the Dutch Association of Pediatrics (NVK), the Initiative on Crohn and Colitis (ICC) and the IBD working group of the Dutch Association of Gastrointestinal Liver Physicians (NVMDL), can facilitate national collaboration in registries. • Additionally, both government, healthcare payers and pharmaceutical companies are more inclined to contribute if the registry provides the information they need or desire. For government and healthcare payers this includes healthcare costs and outcomes. For pharmaceutical companies this includes information they (may) need for post- authorization safety studies (PASS) and post-authorization efficacy studies (PAES) required by EMA. Currently, multiple registries exist, such as the IBDream registry (adult IBD patients), the international ImproveCareNow Registry (both adult and pediatric IBD patients), and the international PIBD-NET Inception Cohort and Safety Registry (pediatric IBD patients). These registries were either founded recently and/or their data was not available for us to use in this thesis. For pediatric CD patients, routine, systematic and uniform registration of treatment outcomes is even more important than for adult CD patients, because most phase 3 clinical trials for innovative medicines only include adults while pediatric phase 3 trials at best are performed with an average delay of 10 years. Registries could provide high quality data on the real-world effectiveness and safety of these medicines in pediatric patients.