Children with a chronic disease face more obstacles than their healthy peers, which may impact their physical, social-emotional, and cognitive development. In the long run, children with a chronic disease reach developmental milestones later than their healthy peers and many children will remain dependent on medication and/ or will be limited in their daily life activities. The PROactive Cohort Study aims to assess fatigue, participation, and psychosocial well-being across children with various chronic diseases over the course of their lifespan since their increased vulnerability is a fact. These factors have the potential to influence their identity and how they grow into autonomous adults that take part in our society. Also the PROactive Cohort Study is aimed at supporting people with chronic and/or life-threatening conditions to increase their ability to adapt, and their self-manage capacities. This means that PROactive also systematically monitors the child's capacity and ability to play and the well-being of the patients and their families. This knowledge can be used as an innovative and interactive method for creating prevention and treatment strategies. This will help to assess vulnerabilities and resilience among children with chronic and/or life-threatening conditions and their families. This cohort study follows a continuous longitudinal design. It is based at the Wilhelmina Children's Hospital in the Netherlands and has been running since December 2016. Children with a chronic disease (e.g. cystic fibrosis, juvenile idiopathic arthritis, chronic kidney disease, or congenital heart disease) in a broad age range (2-18 years) are included, as well as their parent(s). Patient-reported outcome measures (PROMs) are collected from parents (children between 2-18 years) and children (8-18 years). The PROactive Cohort Study uses a flexible design in which the research assessment is an integrated part of clinical care. Children are included when they visit the outpatient clinic and are followed up annually, preferably linked to another outpatient visit.

Children with a chronic disease face more obstacles than their healthy peers, which may impact their physical, social-emotional, and cognitive development. In the long run, children with a chronic disease reach developmental milestones later than their healthy peers and many children will remain dependent on medication and/ or will be limited in their daily life activities. The PROactive Cohort Study aims to assess fatigue, participation, and psychosocial well-being across children with various chronic diseases over the course of their lifespan since their increased vulnerability is a fact. These factors have the potential to influence their identity and how they grow into autonomous adults that take part in our society. Also the PROactive Cohort Study is aimed at supporting people with chronic and/or life-threatening conditions to increase their ability to adapt, and their self-manage capacities. This means that PROactive also systematically monitors the child's capacity and ability to play and the well-being of the patients and their families. This knowledge can be used as an innovative and interactive method for creating prevention and treatment strategies. This will help to assess vulnerabilities and resilience among children with chronic and/or life-threatening conditions and their families. This cohort study follows a continuous longitudinal design. It is based at the Wilhelmina Children's Hospital in the Netherlands and has been running since December 2016. Children with a chronic disease (e.g. cystic fibrosis, juvenile idiopathic arthritis, chronic kidney disease, or congenital heart disease) in a broad age range (2-18 years) are included, as well as their parent(s). Patient-reported outcome measures (PROMs) are collected from parents (children between 2-18 years) and children (8-18 years). The PROactive Cohort Study uses a flexible design in which the research assessment is an integrated part of clinical care. Children are included when they visit the outpatient clinic and are followed up annually, preferably linked to another outpatient visit.