Els van de Vijver

104 Ethical considerations This study was conducted according to the principles of the Declaration of Helsinki (59th version, October 2008). The independent Medical Ethical Committees of the Zuyderland Medical Center (Heerlen, the Netherlands) and the University of Antwerp (Antwerp, Belgium) approved the study (NL42995.096.12; BE17/50/56). Secondary approval was obtained from the boards of the other participating centers. All parents or legal guardians and participants aged 12–18 years gave informed consent. Statistical analysis Patients were considered fatigued when the PedsQL TM fatigue was below -2.0 Z for age, while non-fatigued patients had scores above this cut-off point. Baseline characteristics were compared between fatigued and non-fatigued patients using a Chi-square test for categorical variables and an independent-samples t-test for continuous variables. In case of non-normal distribution, we used non-parametric alternatives (Fischer’s exact test and Mann-Whitney test, respectively; median and IQR are reported). Distributions of PedsQL TM and 6MWD Z-scores among IBD patients were compared with the healthy reference population using the Kolmogorov Smirnov test. RESULTS Baseline characteristics of the study population Patients were recruited between June 2014 and January 2019. Of 124 patients who were assessed for eligibility, 18 were excluded for reasons listed in Figure 1 . A total of 106 patients were included in the final analysis. Chapter 6 104