Inactive disease in polyarticular juvenile idiopathic arthritis: current patterns and associations

OBJECTIVES: To describe the achievement of inactive disease (ID) and remission in polyarticular juvenile idiopathic arthritis (JIA) and to measure the associations among patient characteristics, imaging results and these outcomes. METHODS: We performed a retrospective cohort study of children with polyarticular JIA diagnosed and treated at Seattle Children's Hospital between 1 January 2000 and 31 December 2006. Each patient's disease status (active disease vs ID) was determined for every clinic visit. Adjusted relative risk estimates were obtained using Mantel-Haenszel methods. RESULTS: One hundred and four children were included. Patients were followed up for an average of 30 months. Patients achieved 138 episodes of ID. Fifty-one patients achieved 69 episodes of clinical remission on medication. When duration of active disease was summed over each patient's follow-up, patients spent a mean of 66.3% of their follow-up with active disease. Patients with evidence of joint damage on imaging studies obtained within 6 months of their first clinic visit spent a mean of 79% of their follow-up with active disease. Patients without these findings spent a mean of 58.5% of their follow-up with active disease (P < 0.001). Children who were RF(+) and children with early evidence of joint damage tended to have a higher prevalence of active disease during the follow-up period. CONCLUSIONS: In this cohort, children with polyarticular JIA spent the majority of their follow-up with active disease. Because children with early radiographic evidence of joint damage and children who were RF(+) tended to have the most active disease, improving outcomes for these subgroups may be an important goal for prospective study.