Juvenile idiopathic arthritis (JIA) is one of the most common chronic diseases in children. The results of several epidemiologic studies have shown surprisingly wide variety in the incidence (0.8 to 22.6 per 100,000 children) and prevalence (7 to 400 per 100,000) of this disease.
We performed a retrospective epidemiological study to identify all patients born after 1989 and resident in Asturias who were diagnosed with JIA using the criteria of the International League of Associations for Rheumatology (ILAR) criteria.
Data were obtained from 60 patients (23 boys and 37 girls). The mean age of symptom onset was 5.6 years, with onset of spondyloarthropathies occurring most frequently in the oldest group. An incidence rate of 2.5/10(5) (3.5 at the present time) and a prevalence rate of 51.4/10(5) children and adolescents aged less than 16 years old were calculated. In 50% of patients, JIA started with inflammation in one of the knees. The most frequent form of onset was persistent oligoarticular arthritis (41.7%), followed by spondyloarthropathies (11.7%), conditions that did not meet the criteria for any category (11.7%), polyarticular arthritis (11.7%), systemic disease (10%), psoriatic arthritis (6.7%), and extended oligoarticular arthritis (6.7%). Chronic anterior uveitis was found in 5 patients (pauciarticular group in all 5 patients). Methotrexate was used in 25 children with good response and no relevant adverse events were observed. Only 10% of our patients are currently in the active phase of arthritis.
An incidence rate of 3.5/10(5) and a prevalence rate of 51.4/10(5) children and adolescents aged less than 16 years old in Asturias were calculated (taking into account the possible bias of our study). The most frequent form of onset was persistent oligoarticular arthritis and the most commonly involved joints were the knees.