The prevalence of obstructive sleep apnoea syndrome in ankylosing spondylitis patients

To assess the prevalence of obstructive sleep apnoea syndrome (OSAS) in AS patients.

Thirty-one patients with AS were included in the study. The demographic data, spinal mobility measures and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores were recorded for each patient. All participants underwent one night of sleep recording, which was performed using a polysomnography (PSG). Pulmonary function test (PFT) was performed for all subjects and symptoms of OSAS were questioned.

Seven (22.6%) of 31 AS patients had OSAS according to PSG assessments. The mean BMI, disease duration, BASDAI score, neck circumference and occiput-wall distance were higher in patients with OSAS, but the differences were not significant. The mean ages of patients with OSAS were significantly higher than the patients without OSAS. The prevalence of OSAS in patients under the age of 35 years was found to be 6.3%, whereas the prevalence of OSAS in patients at the age of 35 years or over was 40.0% (P = 0.037). The prevalence of OSAS in AS patients with a disease duration <5 years was 11.8% and its prevalence in AS patients with a disease duration of >or=5 years was 35.7% (P = 0.198). PFT was restrictive in 16 (53.3%) patients and obstructive in none.

The prevalence of OSAS in AS patients is higher than reported in the general population. The diagnosis of OSAS should be kept in mind and OSAS symptoms should be considered especially in AS patients at the age of >or=35 years and in AS patients with a disease duration of >or=5 years.