A cross-sectional survey of the nature and correlates of sleep disturbance in people with psoriasis

BACKGROUND: Research suggests that sleep disturbance is common in psoriasis. Despite 32 studies conducted in sleep, many demonstrate methodological flaws, often using unvalidated measurement, with no study examining multiple dimensions of sleep-wake functioning. Moreover, research has yet to comprehensively examine the range of physical and psychological factors that may affect sleep in people with psoriasis.

OBJECTIVE: To characterise sleep disturbance using validated measures and identify physical and psychological predictors of sleep quality in people with psoriasis.

METHODS: An online survey was conducted (n=186;Mage =39.2) comprising validated measures assessing sleep (Pittsburgh Sleep Quality Index [PSQI], Berlin Questionnaire, Pre-Sleep Arousal Scale), chronotype (Morningness-Eveningness Questionnaire), mood (Hospital Anxiety and Depression Scale), itch (5-D Itch Scale) and psoriasis severity (Simplified Psoriasis Index). Group comparisons and regression analyses were used to examine predictors of poor sleep.

RESULTS: Mean PSQI score was 9.24 (SD=4.32), with 76.3% scoring above the threshold for poor sleep (≥ 6 on the PSQI) and 32.5% scoring 'positive' for probable obstructive sleep apnoea. Poor sleep and high likelihood of OSA was associated with more severe psoriasis (p<.05; η(2) =.07; η(2) =.005). Cognitive arousal (β=.264, p=.001), itch (β=.260, p<.001) and depression (β=.236, p=.001) were the most robust predictors of poor sleep quality which, together with somatic arousal (β=.168, p=.022), accounted for 43% of variance in PSQI scores.

CONCLUSIONS: Poor sleep is common in psoriasis and associated with psychological and physical factors. Rates of probable obstructive sleep apnoea are also high. Given the importance of restorative sleep for health, sleep complaints should receive greater clinical attention in the management of psoriasis. This article is protected by copyright. All rights reserved.