Many people who have juvenile idiopathic arthritis (JIA) have the condition well into adulthood. In adult rheumatology clinics, polyarticular JIA (pJIA) is frequently mislabeled as rheumatoid arthritis (RA), and therapy for adult pJIA patients is not well established. For this study researchers wanted to describe clinical characteristics and medication usage in an adult pJIA population in comparison to a RA control cohort. From 2013 to 2017, they conducted cross-sectional research on 45 persons with pJIA and 94 adults with RA. The χ2 and McNemar tests were used to compare clinical features, including RA categorization criteria. Medication use was examined with a focus on tumor necrosis factor inhibitor (TNFi) survival, and an accelerated failure time model for time to methotrexate initiation was developed.

Patients with polyarticular JIA were less likely to have a rheumatoid factor or cyclic citrullinated peptide antibody positivity; less than half of pJIA cases fulfilled the RA 2010 American College of Rheumatology/European League Against Rheumatism Classification Criteria.  In both groups, the time from diagnosis to methotrexate beginning was linked with a longer illness duration (p < 0.01). Current TNFi usage was higher in pJIA patients (49% vs. 18%, p < 0.01), and TNFi use, particularly for etanercept, was maintained for a longer period of time, with a median drug survival of 4.41 years compared to 0.70 years in RA patients (p < 0.01).

Adults with pJIA are separate from those with RA, despite the fact that they are frequently regarded together in adult rheumatology therapy. Medication usage differed significantly between the two populations, with pJIA patients having a higher prevalence and duration of TNFi use. More research is required to enhance results in this specific demographic.