LAUSR

To evaluate the drug treatment trends in patients with incident juvenile idiopathic arthritis (JIA) in 2006–2014. In Finland, patients are entitled to a special reimbursement for medication if their condition meets certain criteria. We gathered all reimbursement decisions with the ICD-10 diagnosis of M08 for patients under 16 years of age from a nationwide register maintained by Kela, the Social Institution of Finland. A total of 2439 incident cases of JIA were identified. We surveyed their reimbursable drugs purchased for the first time for JIA upon a doctor’s prescription in 3-year cohorts (2006–2008, 2009–2011, 2012–2014). Changes of drug treatment for JIA became more active during our study years. Between 2006–2008 and 2011–2014, the introduction of methotrexate (MTX) for the first time within the first 3 months increased from 73% (2006–2008) to 90% (2011–2014) of the patients, IRR (incidence rate ratio) was 1.23 (95% CI 1.10–1.37). The use of parenteral MTX increased even more; IRR was 1.97 (95% CI 1.61–2.41). During the first 2 years of their disease, 18% of the first cohort received subcutaneous biologic agents, while the corresponding proportion in the last cohort was 31%. Biologic agents were more likely to be introduced for patients with early (3 months) MTX administration than for patients without early MTX introduction; HR (hazard ratio) 2.19 (95% CI 1.63–2.93). During the follow-up, MTX administration became more prevalent for the treatment of JIA soon after diagnosis, mostly because of the increase in the use of parenteral MTX. Key Points • The drug therapy for treating juvenile idiopathic arthritis has changed during recent years. • Methotrexate, some other conventional DMARDs, and biologic DMARDs are introduced earlier.