Early predictors of outcome in juvenile idiopathic arthritis.

The definition and management of "early arthritis" in children differ from those in adults because juvenile idiopathic arthritis (JIA) is markedly different from adult rheumatoid arthritis. Since a significant proportion of patients with JIA develop articular damage and enter adult life with persistently active disease, it is important to predict early in the disease course the long-term outcome in order to tailor treatment to the risk of disability. Over the past 3 decades a number of studies have evaluated the long-term outcome of cohorts of patients with JIA and some of them have also attempted to identify early prognostic factors. In summary, greater severity/extension of arthritis at onset, symmetric disease, precocious hip/wrist involvement, the presence of rheumatoid factor, and prolonged active disease were the best predictors of a poor outcome. Specific correlates for systemic JIA were persistent systemic features and thrombocytosis at 6 months following presentation, whereas joint symmetry and a higher erythrocyte sedimentation rate at onset were associated with a more severe course in oligoarticular JIA. However, although data is accumulating on prognostic factors in JIA, prediction of long-term outcome in the first few months remains difficult. To better define prognostic factors in future analyses, a considerable effort should be made to increase standardization among studies. Furthermore, a radiographic scoring system and a set of remission criteria specific for JIA should be developed.