Use of Tumor Necrosis Factor-Alpha Inhibitors in Children and Young Adults With Juvenile Idiopathic Arthritis or Rheumatoid Arthritis

Objective To characterize the use of tumor necrosis factor‐α inhibitors (TNFIs) in children with juvenile idiopathic arthritis (JIA) and young adults with rheumatoid arthritis (RA). Methods Patients with incident JIA or RA were identified by using the Truven Health MarketScan Commercial Claims and Encounters database from 2009 to 2013. The incident diagnosis was defined as no prior claims with a JIA/RA code and no JIA/RA medications recorded during the previous 6 months. TNFI use patterns were examined, including switching among TNFIs, adherence, persistence, and time from diagnosis to TNFI use. Earlier TNFI treatment without prior use of traditional disease‐modifying antirheumatic drugs (DMARDs) and use of specific TNFIs were analyzed by age group. Results Of 6929 children and young adults with new diagnoses of JIA/RA, 18.6% were treated with TNFIs. In these TNFI users, 39.1% received earlier TNFI therapy without prior use of DMARDs. The use of TNFIs was higher in patients diagnosed between 2012 and 2013 than that in patients diagnosed between 2009 and 2011 (hazard ratio 1.13, 95% confidence interval 1.00–1.28). Etanercept was the most commonly used, especially by children aged < 12 (75.5%) and adolescents aged 12 to 17 (62.5%) years. Adherence measured as mean proportion of days covered ranged from 70.4% to 93.2% for individual TNFI agents. Only about 60% of patients continuously took TNFIs for 12 months. When switching occurred, switching from etanercept to adalimumab was the most common pattern. Conclusion Earlier TNFI therapy was observed in 39.1% of children and young adults taking TNFIs. In addition, the time to the first TNFI prescription became shorter over the study period. Future research should evaluate the long‐term effectiveness and safety of this more aggressive TNFI therapy.