Epidemiology and comorbidity of juvenile idiopathic arthritis in Poland – a nationwide study

Abstract

Background Over time, the revised juvenile idiopathic arthritis (JIA) classification and a shift towards goal-oriented treatment with disease-modifying drugs (DMARDs) may have changed the epidemiologic landscape of JIA. Methods Public healthcare utilization records from the National Health Fund (NHF) were screened between 2010–2022. For individuals aged < 16 years, we utilized a narrow JIA case definition combining repeat ICD-10 encoding with DMARDs prescription based on ATC codes. Results Of 37 mln patients in the NHF database, 29 758 individuals fulfilled our case definition. Over time, the number of newly detected cases ranged between 1381–2394. In 2022, the incidence and prevalence rate per 100,000 persons was calculated at 4.14 and 73.9, respectively. Stable incidence trends were observed with mean incidence rate estimated at 5.65 (95%CI 4.80–6.50). Gender-related differences confirm JIA susceptibility among females. Among JIA-related comorbidities, allergic rhinitis (N = 5 200, 17.5%), bronchial asthma (N = 3 661, 12.3%) and growth restriction (N = 2 311, 7.8%) were common. Over 214 285 visits, we calculated the total and median cost of JIA treatment at over 3.54 mln€ and 232 000€, respectively. Conclusions This is a comprehesive, nationwide study that provides a contemporary estimate for JIA burden and cost in Poland.