Doeleman MJH, de Roock S, Buijsse N, et al. - In this retrospective monocentric study, experts aspired to explore whether self-assessment with the EuroQol five-dimensional ‘youth’ questionnaire with five levels (EQ-5D-Y-5 L) inside a mobile E-health application could identify juvenile idiopathic arthritis (JIA) patients in need of possible treatment adjustments. Between October 2017 and January 2019, the EQ-5D-Y-5 L was completed through a mobile application (Reuma2Go). Sixty-eight JIA patients finished the EQ-5D-Y-5 L questionnaire. The results show that in the studied population, the EQ-5D-Y-5 L was able to identify JIA patients in need of possible treatment adjustments. Remote monitoring of the health-related quality of life and patient-reported outcomes via E-health applications could provide valuable additional information for determining the frequency of clinical visits, assessing therapeutic efficacy, and guiding treat-to-target strategies in pediatric JIA patients.