Prevalence and factors associated with disturbed sleep in outpatients with ankylosing spondylitis

Sleep disturbance is prevalent among patients with ankylosing spondylitis (AS) and is considered a multifactorial issue. The study was designed to investigate sleep disturbance and its associated factors in AS outpatients in Southwest China. Patients were recruited by convenience sampling in this cross-sectional study. The Pittsburgh Sleep Quality Index (PSQI), the Bath AS Disease Activity Index (BASDAI), the Bath AS Functional Index (BASFI), the Bath AS Patient Global Score (BAS-G), and the Hospital Anxiety and Depression Scale (HADS) were used to assess sleep quality, disease activity, function status, global well-being, depression, and anxiety. Spearman's correlation, t test, ANOVA, and multiple linear regression analysis were used to explore the associated factors of sleep disturbance. Of the 281 outpatients included in the study, 190 (67.6%) patients had sleep disturbance. The married patients, the patients with extra-spinal manifestation, depression and anxiety, longer duration of diagnostic delay, higher disease activity, worse functional status and global well-being, high level of pain, and fatigue, had poorer sleep quality (P < 0.05). Multiple linear regression analysis revealed age (β = 0.087, P = 0.102), BAS-G (β = 0.181, P = 0.003), fatigue (β = 0.170, P = 0.002), anxiety (β = 0.151, P = 0.002) and nocturnal back pain (β = 0.192, P = 0.001), extra-spinal manifestation (β = 0.120, P = 0.012), and duration of diagnostic delay (β = 0.174, P = 0.001) were the contributors to PSQI. Sleep disturbance is common in AS patients in Southwest China. It may be useful to keep regular exercise, strengthen the management of pain, relieve anxiety, and prevent and treat extra-spinal manifestation for improving sleep quality.