Background: Juvenile idiopathic arthritis (JIA) is a heterogeneous group of disorders. Publications from different countries point to differences in the disease manifestation of JIA among different populations. The aim of the present paper was to evaluate the clinical and laboratory features of JIA in Turkish children.
Methods: A total of 196 JIA patients who fulfilled International League of Associations for Rheumatology (ILAR) diagnostic criteria were included in this retrospective study. The data collected were age, gender, age at disease onset and at diagnosis, and follow-up duration. Antinuclear antibody (ANA), rheumatoid factor (RF), and human leukocyte antigen B-27 were evaluated for each patient.
Results: There were 102 boys and 94 girls with a mean duration of disease of 4.1 years. The mean age at the first visit was 8.8 years, and the mean age at onset of disease was 6.8 years (range, 8 months-15 years). Polyarticular JIA was the most frequent onset type (37.2%). Other subtypes included oligoarthritis (34.2%), systemic arthritis (15.3%), psoriatic arthritis (1%), enthesitis-related arthritis (9.7%), and other arthritis (2.2%). ANA was positive in 28 patients (14.2%). Chronic uveitis occurred in two patients with oligoarthritis; and two patients with enthesitis-related arthritis had acute uveitis. Three patients (1.4%) developed amyloidosis.
Conclusion: Compared to reports from Western countries, remarkably different features of JIA were found in Turkish children, which included higher frequency of polyarticular JIA, higher prevalence among boys, lower rate of ANA positivity and uveitis. Further studies are required to understand how genetic and environmental differences affect JIA expression.