Nationwide epidemiological survey of juvenile idiopathic arthritis during transition to young adulthood in Japan using the National Database of Designated Incurable Diseases of Japan.

This article focuses on assessing the unmet medical needs and treatment patterns of young adults aged 20-29 with juvenile idiopathic arthritis (JIA) using data from the National Database of Designated Incurable Diseases of Japan (NDDIDJ). Analysis of 322 patients revealed frequent use of methotrexate and biological disease-modifying antirheumatic drugs (bDMARDs) across all JIA subtypes, with higher methotrexate use in rheumatoid factor-positive polyarthritis (RF(+)pJIA) and oligoarthritis/polyarthritis compared to systemic arthritis (sJIA). The study highlights that many patients transitioning to adulthood require high-cost treatments, particularly bDMARDs, indicating ongoing disease activity and financial burden. Limitations include the database's focus on severe cases requiring costly care, excluding patients in remission or with low disease activity, and lack of detailed dosage or quality-of-life data. The authors call for further research on medical interventions and support systems for this population.