Measurement of health status, functional status, and quality of life in children with juvenile idiopathic arthritis: clinical science for the pediatrician.

There has been a tremendous emphasis on the development of measures of function and HRQoL for application in JIA over the past 15 years. Of the measures that are currently available, the CHAQ and the CHQ are the most widely used, although the use of others, including the JAQQ, the Peds QL, and the QoMLQ, is growing. As evidence emerges from better longitudinal studies with these measures, it will be possible to describe patient outcomes in JIA more accurately. From the outcome studies that have been conducted to date, one can conclude that JIA is not a benign disease. It frequently continues into adulthood, and most remissions occur in the first 5 years after disease onset. The probability of remission 10 years after onset approximates 30% to 35%, overall, and decreases progressively thereafter. Thus, if remission does not occur within 10 years of disease onset, it is unlikely to occur at all. Although remission rates have not changed substantially, functional outcomes have improved tremendously, with fewer patients exhibiting severe outcomes. Nonetheless, the degree of impaired functional outcome is still unacceptable and needs to be improved. Significant joint damage is still a consequence of this disease, with relatively high rates of arthroplasty, and increasing data reveal significant problems of osteopenia and osteoporosis that are not being addressed adequately. A large prospective study with strict application of the JIA classification, using the new definitions of remission and disease flare and coupled with the use of the newer functional and HRQoL measures will provide more accurate outcome data and better means of predicting good and poor outcomes. Such a study is under way in Canada. It will be interesting to see if there is a significant change in remission rates in this study, because the current approach to therapy, especially with the availability of biologic agents, is more aggressive than that used in most patients in the reported studies. Pediatricians need to be aware of this change in approach and should refer patients for evaluation to a pediatric rheumatologist early in the disease course to maximize ultimate patient outcomes.