To analyse the demographics, main clinical and laboratory features and subtype distribution of juvenile idiopathic arthritis (JIA) in an eastern Mediterranean country, based on a multicentre registry.
Between March 2008 and February 2009 with this cross-sectional study, consecutive patients seen with JIA in selected centres were registered through a web-based registry. All patients were classified according to the International League of Associations for Rheumatology (ILAR) criteria.
There were 634 patients with a mean age of 11.84 ± 4.66 years and the female/male ratio was 1.2. The distributions of JIA patients according to onset of disease were as follows: systemic 92 (14.5%), oligoarticular extended 26 (4.1%), oligoarticular persistent 234 (36.9%), rheumatoid factor (RF) positive polyarthritis 20 (3.2%), RF negative polyarthritis 129 (20.3%), enthesitis-related 120 (18.9%), psoriatic 13(2.1%). The frequency of uveitis was 15.7% among all of the oligoarthritis patients. Anti-nuclear antibody (ANA) was positive mainly among the oligoarticular onset patients. Twenty-one patients also had Familial Mediterranean fever (FMF). Among systemic JIA patients, the frequency of macrophage activation syndrome (MAS) was 15.2% (n=14). At the end of the mean follow-up of 7.6 ± 4.4 years, 305 (48.1%) patients were defined to have inactive disease on medication, and 106 (16.7%) were completely free of any disease symptoms without medication.
Enthesitis related arthritis had a high frequency whereas psoriatic arthritis was very rare compared to other series. We suggest that there are certain differences in the characteristics of JIA in our eastern Mediterranean population. Thus, genetic studies need to be assessed in these populations separately and findings of genome wide association studies need to be confirmed in different populations.