Outcome following onset of juvenile idiopathic inflammatory arthritis: I. frequency of different outcomes.

OBJECTIVE: To determine the outcome, following the onset of juvenile idiopathic inflammatory arthritis, in terms of remission of disease activity, loss of function and structural damage based on a review of the available published data.
METHODS: Electronic databases were searched for major studies publishing outcome data in the past 10 yr in juvenile idiopathic arthritis, juvenile rheumatoid arthritis and juvenile chronic arthritis, and 21 studies were selected. The proportions of children in the different categories of the outcomes of interest are described. Data were stratified where possible by disease subtype.
RESULTS: There were major differences between the studies reviewed in terms of study design, case selection and the results obtained. In general, children with systemic- or polyarticular-onset disease were much less likely to go into remission than those with oligoarticular onset, although the remission rates in the latter group ranged from 36 to 84%. Several different approaches were used to assess functional outcome but the pattern of results between the different subgroups was the same as with remission. Similarly, children with polyarticular disease in all the cohorts reviewed were substantially more likely to have erosive radiological damage on follow-up. The rates of individual outcomes, even within a subgroup, varied considerably between studies and this does not appear to be explained solely by differences in methodology.
CONCLUSIONS: There remains a considerable lack of clarity in the prognosis following onset of juvenile idiopathic arthritis for the major outcomes considered, although those with oligoarthritis at presentation have the best outcome. The ability to offer accurate prognosis is particularly important to both reassure parents and guide treatment at disease onset. To achieve this, large definitive prospective studies will be required.