In a long-term follow-up study, many people with juvenile idiopathic arthritis (JIA) still had active disease with a heavy medication burden and low remission rates 18 years after diagnosis, according to a report published in Arthritis Care & Research. Data show that those with enthesitis-related arthritis (ERA) had the poorest outcomes.

Since biologic medication first became available 20 years ago, there has been ongoing debate regarding extended outcomes. Investigators sought to characterize disease activity, medication use, and remission rates in patients with JIA in a population-based setting.

The trial enrolled 510 consecutive patients with JIA diagnosed between 1997 and 2000 to assess clinical outcomes 18 years later. Clinical examination and serology were performed at the follow-up visit for those able to be seen in person (n=329), and phone interviews were conducted for the remaining participants. Primary outcomes were disease activity, medication regimen, and clinical remission status. Measures used to evaluate outcomes included the Juvenile Arthritis Damage Indexes (JADI-A and JADI-E), and the composite juvenile arthritis disease activity score (JADAS71), which ranges from 0 to 101 (<1 showing inactive disease).

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A total of 434 of 510 patients (mean age, 23.9 years; 68.4% women; mean age at onset, 6.5 years; mean disease duration, 17.5 years) were analyzed at follow-up. Although the entire cohort had relatively mild active disease, with a median JADAS71 of 1.5, those with ERA (10.4%) had considerably greater disease activity, with a median JADAS71 of 4.5, which was the highest of all JIA subtypes (P =.003). At 18 years, 45.6% of the entire cohort still had active disease, whereas disease in 48.3% was categorized as inactive. Of those with ERA, 64.9% had active disease. There were 65 (19.8%) individuals with articular damage (JADI-A) and 41 (12.5%) with extra-articular damage (JADI-E).

At 18 years, 66 (15.2%) people were receiving synthetic disease-modifying antirheumatic drugs (DMARDs) and 84 (19.4%) were taking biologics, while 306 people (70.5%) were receiving no medication. Patients with ERA were taking significantly more biologics (37.8%) than those with all other subtypes (P =.01). There were 189 (43.5%) participants who had received no medication in the past 10 years. In addition, 259 (59.7%) had used DMARDs at some point and 128 (29.5%) had been taking biologic medications. Patients with ERA were most likely to receive biologic treatment (51%) and those with rheumatoid factor-negative polyarticular arthritis most often received DMARDs (87%).

Complete remission off medication was achieved by 32.8% of the cohort seen in person at follow-up, with another 10% achieving remission on medication for ≥6 months. Those with systemic JIA and persistent oligoarticular subtypes saw the highest remission rates, at 53.8% and 54.2%, respectively. Those with ERA subtype had the lowest rate of remission, at 8.1%, which was significantly lower than for all other categories (P <.001).

Study strengths included a prospective design, population-based setting, acceptable drop-out rate (15%), validated outcome metrics, and low genetic variability within the sample.

Study limitations included questionable validity of telephone responses, use of uncertain subjective remission from phone interviewees, lack of reported data between 8 and 18 years, and low levels of early biologic therapy.

“The study adds to the evidence that a substantial proportion of patients continue to have active disease, and the burden of medication is extensive in JIA, even 18 years after disease onset,” the authors noted.

Reference

Glerup M, Rypdal V, Arnstad E D, et al. Long-term outcomes in juvenile idiopathic arthritis: 18 years of follow-up in the population-based Nordic juvenile idiopathic arthritis (JIA) cohort [published online February 14, 2019]. Arthritis Care Res (Hoboken). doi:10.1002/acr.23853