[Sleep quality in patients with ankylosing spondylitis]

Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease characterized by the inflammation of the pelvis and spine that results in a restriction in the mobility of the spine. Due to the altered posture and nocturnal inflammatory pain, sleep disturbances are likely to occur in patients with AS.

This cross-sectional study aimed at determining the differences between the patients with AS and healthy controls in sleep quality, as well as assessing the relationship between the sleep quality and disease activity.

In order to assess sleep quality, fifty-five patients with AS (40 men, 15 women; mean age, 43 ± 1 yrs) who fulfilled the modified New York criteria and fifty-five comparable controls (40 men, 15 women; mean age, 42 ± 9 yrs) completed the Pittsburgh Sleep Quality Index (PSQI) questionnaire. The disease activity was assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

Ankylosing spondylitis was associated with a significantly impaired sleep quality according to the total PSQI scores (p = 0.001). Significant differences were found between the patients with AS and healthy controls in PSQI domains, including "subjective sleep quality" (p = 0. 010), "sleep duration" (p = 0. 011), "habitual sleep efficiency" (p = 0. 034), "sleep disturbances" (p = 0. 003) and "daytime dysfunction" (p = 0. 009) but not in "sleep latency", "use of sleep medication". There was a significant positive correlation between the BASDAI and PSQI scores (r = 0.612, p = 0.001).

In the current study, we found that the sleep disturbances were significantly higher in patients with AS in comparison to controls. Patients with active disease had worse sleep quality. In addition, disease activity was correlated with the scores of most of the PSQI subscales. Sleep quality assessment should be a tool for evaluating patients with AS.