Data collection and measures
Castor EDC
Clinical data of the children were prospectively collected by trained clinicians using a standardized electronic case report form (Castor EDC), including age at onset (years), sex (male/female), cumulative prednisolone dose (mg/mParents completed a survey on sociodemographics (age, sex, family situation, marital status, education). For Belgian children, versions appropriate for language (Flemish or French) were available. Two PROMs (Pediatric Quality of Life Inventory and Strengths and Difficulties Questionnaire) with appropriate versions for different age groups, were used to measure HRQoL and EBD.