RESUMEN
OBJECTIVES: To describe the methodology, objectives, and initial data of the registry of young adult patients diagnosed with Juvenile Idiopathic Arthritis (JIA), JUVENSER. The main objective of the project is to know the sociodemographic and clinical characteristics, and disease activity of patients with JIA reaching the transition to adulthood. MATERIAL AND METHOD: Longitudinal, prospective, multicentre study, including patients between 16 and 25 years old, with a diagnosis of JIA in any of its categories. The main objective is to determine the characteristics and activity of JIA in the young adult. It includes sociodemographic variables, clinical variables, disease activity and joint damage rates, data on the use of health resources, and treatments used. The total duration of the project will be 3 years. A cohort of 534 young adult patients was obtained. CONCLUSIONS: The JUVENSER registry will constitute a cohort of young adults with JIA, which will allow the evaluation of the clinical characteristics and response to treatment of patients with disease onset in childhood, moving to adult clinics.