Prevalence of ankylosing spondylitis and related spondyloarthritides in an urban area of Izmir, Turkey.

Abstract

To determine the prevalence of ankylosing spondylitis (AS) and related spondyloarthritides (SpA) in an adult urban population of Izmir, Turkey. A survey was conducted of 2887 subjects aged 20 years or over, selected by cluster sampling. Those who responded positively to the screening questions were contacted by 2 rheumatologists and evaluated in detail to establish presence of AS (modified New York criteria) or related SpA (ESSG criteria). In the initial screening, 2835 subjects participated; 422 were considered screening-positive and a telephone interview was done with 328 (78%). Based on their clinical history, 145 subjects were invited to the hospital and 120 (83%) agreed to do so. After detailed evaluation, 31 subjects were classified as having SpA (including 14 with AS). The age- and sex-adjusted prevalence was estimated to be 0.49% for AS (95% CI 0.26-0.85), and 1.05% for SpA (95% CI 0.70-1.50). The prevalence of AS was 0.54% in men (95% CI 0.19-1.20) and 0.44% in women (95% CI 0.19-0.88), and that of SpA was 0.88% in men (95% CI 0.42-1.59) and 1.22% in women (95% CI 0.73-1.89). This epidemiological study suggests a high prevalence (0.49%) of AS in an adult urban population from western Turkey, which equals that of rheumatoid arthritis in the same population. The overall prevalence of SpA, including AS, was 1.05%. A minimal male predominance was noted among AS patients, which disappeared among the whole group of patients with SpA.