Systemic onset juvenile idiopathic arthritis: A retrospective study of 80 consecutive patients followed for 10 years

Objective. To investigate the relationships between systemic onset juvenile idiopathic arthritis disease activity, course of the disease, and function al class according to Steinbrocker. Methods. The records of all children with systemic onset juvenile arthritis (JA) according to the American College of Rheumatology criteria attending our center since 1971 with a minimum followup period of 3 years were review ed, A cohort of 80 consecutive patients entered the study: 42 males, 38 fem ales, mean age at onset 6.3 years (range 0.7-16), mean followup period 10.7 years (range 3-33), The cumulative duration of the active periods (CDAP) i n months was calculated for every patient. Results. Three patterns of disease course were apparent: monocyclic (subtyp e I), intermittent (subtype II), and persistent (subtype III). At the last control the functional class and disease activity status were evaluated. In all subtype I patients (9 cases) the disease was in remission and no patie nt was in class II, III, or IV. In subtype II patients (27 cases), 16 were inactive or in remission and 6 in class III. In subtype III (44 cases) 21 w ere inactive or in remission and 17 were in class III or IV. The equation r elating the Steinbrocker class to the CDAP was calculated considering the f unctional outcome as the dependent variable. The linear regression equation y = 0.0083 x + 1.266 was found with a correlation coefficient r = 0.586 (p < 0.0001). The majority of our patients were treated with disease modifyin g antirheumatic drugs, which in many cases were effective in reducing the d uration of the active phases of disease. Conclusion. Systemic onset JA may present with different clinical courses; the functional outcome is always good in subtype I (monocyclic), but can be poor in subtypes II and III. The severity of disability evaluated accordin g to Steinbrocker classes is dependent on the cumulative duration of the ac tive periods of the disease.