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

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.

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.

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.

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.