Pattern of disease onset, diagnostic delay, and clinical features in juvenile onset and adult onset ankylosing spondylitis.

Objective: To assess the frequency of juvenile onset ankylosing spondylitis (JOAS) in Turkish patients with AS and to compare with adult onset AS (AOAS) in a cross-sectional study design.
Methods: A total of 322 patients were recruited from the joint database of 5 university hospitals in eastern Turkey.
Results: Patients with JOAS (n = 43, 13.4%) had significantly longer diagnostic delay (9.21 vs 5.08 yrs), less severe axial involvement and more prevalent uveitis (OR 2.92, 95% CI 1.25-6.79), and peripheral involvement at onset (OR 3.25, 95% CI 1.51-6.98, adjusted for current age; and OR 2.26, 95% CI 1.07-4.76, adjusted for disease duration). Patients with AOAS had higher radiographic scores and more restricted clinimetrics but similar functional limitations and quality of life.
Conclusion: JOAS and AOAS had distinctive courses and Turkish patients with AS had similar features compared to other Caucasian patient populations.