RESUMEN
We report herein the results of the cross-cultural adaptation and validation into the Chilean language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Chilean CHAQ-CHQ were derived from the European Spanish version with changing of the few words whose use is different in the 2 countries. A total of 126 subjects were enrolled: 72 patients with JIA (29% systemic onset, 39% polyarticular onset, 4% extended oligoarticular subtype, and 28% persistent oligoarticular subtype) and 54 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the JIA patients having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the JIA patients having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Chilean version of the CHAQ-CHQ is a reliable, and valid tool for the functional, physical and psychosocial assessment of children with JIA.