RESUMEN
The Juvenile Arthritis Multidimensional Assessment Report (JAMAR) is a new parent/patient-reported outcome measure that enables a thorough assessment of the disease status in children with juvenile idiopathic arthritis (JIA). We report results of the cross-cultural adaptation and validation of the parent and patient versions of the JAMAR in the Czech language. The reading comprehension of the questionnaire was tested in ten JIA parents and patients. The participating centre was asked to collect demographic and clinical data along the JAMAR questionnaire in 100 consecutive JIA patients or all consecutive patients seen in a 6-month period and to administer the JAMAR to 100 healthy children and their parents. The statistical validation phase explored descriptive statistics and the psychometric issues of the JAMAR: the three Likert assumptions, floor/ceiling effects, internal consistency, Cronbach's alpha, interscale correlations, test-retest reliability, and construct validity (convergent and discriminant validity). A total of 103 JIA patients (5.8% systemic, 35.9% oligoarticular, 37.9% RF-negative polyarthritis, 20.4% other categories) and 100 healthy children, were enrolled. The JAMAR components discriminated well healthy subjects from JIA patients. Notably, there was no significant difference between healthy subjects and their affected peers in the school-related problems variable and in the Psychosocial Health of the Paediatric Rheumatology Quality of Life scale. All JAMAR components revealed good psychometric performances. In conclusion, the Czech version of the JAMAR is a valid tool for the assessment of children with JIA and is suitable for use both in routine clinical practice and clinical research.