Sleep Disturbances in Korean Patients with Ankylosing Spondylitis are Associated with Increased Disease Activity

Abstract

Objective. To evaluate the prevalence of sleep disturbance in Korean patients with ankylosing spondylitis (AS), and its association with disease activity and depression. Methods. Forty patients with AS and eighty healthy controls were included in this study. Sleep quality was assessed using the Korean version of Pittsburgh sleep quality index (PSQI). Depression was assessed by the Korean version of Beck depression inventory second edition (BDI-2). Ankylosing spondylitis disease activity score-C-reactive protein (ASDAS-CRP) was used to evaluate disease activity. Patients were dichotomized into a good sleeper group (PSQI≤5) and a poor sleeper group (PSQI>5). Results. The mean total PSQI score of patients with AS was 7.23±3.84. It was higher than that of the control subjects. AS patients had higher scores in all of the PSQI components, except for the use of sleep medication. Sixty percent of the AS patients were classified as poor sleepers. The mean BASDAI, ASDAS-CRP, and BDI-2 scores of the poor sleeper group were higher than that of the good sleeper group. Significantly, higher disease activity according to ASDAS-CRP was associated with poor sleep quality and depression. Multiple regression analysis revealed that the duration of morning stiffness and depression were independent risk factors that influenced poor sleep quality. Conclusion. Sleep disturbances are prevalent amongst Korean patients with AS. Lower quality of sleep is significantly associated with higher disease activity and depression. Therefore, optimal management to improve sleep quality in patients with AS is important.