Maarten Cozijnsen

147 Chapter 7 General discussion Routine registration of treatment outcomes would facilitate observational research Two additional aims of this thesis focused on assessing benefits and risks of treatment given in routine clinical practice: to evaluate the real-world effectiveness of adalimumab and to compare the benefits and risks of combining anti-TNF and immunomodulator therapy with anti-TNF monotherapy. We used two different approaches to answer these research questions (a retrospective, observational case series and a literature review). • We evaluated the real world effectiveness and safety of adalimumab therapy for pediatric CD in an observational case series ( Chapter 5 ). Because of its observational character, it reflects daily practice and includes a broad spectrum of patients. However, the retrospective design had several limitations. We missed information on endoscopic remission in the patients treated with adalimumab. A score for mucosal inflammation – such as the SESCD – after endoscopic examination was not routinely registered in clinical practice. Furthermore, for part of the patients and timepoints, we had missing data. And thirdly, not all patients were treated in the same way with respect to dosing and concomitant medication, and also the reasons to initiate adalimumab varied. • We compared the benefits and risks of combining anti-TNF and immunomodulator therapy with anti-TNF monotherapy using a literature review ( Chapter 6 ). Unfortunately, there were not many high quality publications to review that make this comparison in pediatric CD and ulcerative colitis (UC) patients. Because of this lack of information, we partly based our conclusions on results of trials performed in adult patients. If physicians would register treatment outcomes more systematically and completely as part of routine clinical practice, these research questions could have been answered more easily and reliably with observational research. Also, physicians and hospitals would need to register the data uniformly so that data of multiple centers can be analyzed combinedly. Routinely and uniformly registered data could be collected in a national (or international) patient registry. This would make observational research less time consuming and costly. For research purposes, the larger the registry the better (for statistical power) and the more information the better (more information allows conclusions on more diverse topics). The biggest challenge for registries is getting the required structural finances to sustain their activities. Besides research funds, potential additional funding sources include the government, healthcare payers and for profit companies active in healthcare (such as pharmaceutical companies).