Objectives Juvenile idiopathic arthritis (JIA) is subdivided into seven categories. Even within these categories, the prognosis varies markedly. To start appropriate treatment in patients with JIA and to inform patients and their parents correctly, it is essential to know the individual prognosis, preferably at the time of diagnosis. The aim of this study was to identify variables that predict disease activity, joint damage, functional ability and quality of life (QoL) early in the disease course.

Methods A systematic literature review was performed, and 3679 articles were identified. The results were screened and critically appraised using predefined criteria. Articles that described validated outcomes, such as the Wallace criteria, the childhood health assessment questionnaire (CHAQ) and the juvenile arthritis damage index (JADI), and that determined predictors in the first 6 months of disease were selected.

Results Forty mostly retrospective articles were selected. Polyarticular onset predicted a worse prognosis for all outcomes, except QoL. A diagnostic delay and the systemic category predicted continuation of active disease. Notably, antinuclear antibodies (ANA) did not predict disease activity. Symmetric involvement and rheumatoid factor positivity predicted less damage. More disease activity was mainly associated with worse functional outcome. However, most predictors were not validated.

Conclusions Few predictors for the selected outcomes were found. Prospective, longitudinal studies using standardised outcome measurements, and evaluating a broader range of predictors, such as genetics, immunological and imaging data, should be performed. For the outcomes joint assessment and quality of life, standardised and validated outcomes should be developed.