Developing outcome measures for paediatric rheumatic diseases.

This review provides a theoretical background and approach for developing outcome measures that are often used to assess the state and course of paediatric rheumatic diseases. It describes the important steps in scale development such as item generation and reduction, the assessment of scale reliability and various forms of validation. The second part of this review described the newly developed outcome measures as well as their state of validation. These outcome measures include therapeutic response measures, composite disease activity scores for juvenile idiopathic arthritis (JIA), global disease activity tools for juvenile systemic lupus erythematosus and juvenile dermatomyositis, disease status measures in JIA, measures of physical function, measures of health-related quality of life, clinical measures of damage and radiographic scoring systems in JIA.