A call for improved sleep research in psoriasis populations

Factors Influencing Sleep Difficulty and Sleep Quantity in the Citizen Pscientist Psoriatic Cohort

INTRODUCTION

Sleep is essential for overall health and well-being, yet more than one-third of adults report inadequate sleep. The prevalence is higher among people with psoriasis, with up to 85.4% of the psoriatic population reporting sleep disruption. Poor sleep among psoriasis patients is particularly concerning because psoriasis is independently associated with many of the same comorbidities as sleep dysfunction, including cardiovascular disease, obesity, and depression. Given the high prevalence and serious consequences of disordered sleep in psoriasis, it is vital to understand the nature of sleep disturbance in this population. This study was designed to help meet this need by using survey data from Citizen Pscientist, an online patient portal developed by the National Psoriasis Foundation.

METHODS

Our analysis included 3118 participants who identified as having a diagnosis by a physician of psoriasis alone or psoriasis with psoriatic arthritis. Demographic information, psoriasis severity and duration, sleep apnea status, smoking and alcohol consumption, itch timing, and sleep characteristics were included. Two separate multivariate logistic regression models in STATA were used to determine whether the presence of psoriatic arthritis, age, gender, body mass index, comorbid sleep apnea, psoriasis severity, timing of worst itch, smoking status, or high-risk alcohol consumption were associated with sleep difficulty or low sleep quantity, defined by the American Academy of Sleep Medicine as less than 7 h of sleep per night on average.

RESULTS

Results from the multivariate logistic regressions found that sleep difficulty was associated with psoriatic arthritis (OR 2.15, 95% CI [1.79-2.58]), female gender (2.03 [1.67-2.46]), obese body mass index (BMI ≥ 30) (1.25 [1.00-1.56]), sleep apnea (1.41 [1.07-1.86]), psoriasis severity of moderate (1.59 [1.30-1.94]) or severe (2.40 [1.87-3.08]), and smoking (1.60 [1.26-2.02]). Low sleep quantity was associated with obese BMI (1.62 [1.29-2.03]), sleep apnea (1.30 [1.01-1.68]), psoriasis severity of moderate (1.41 [1.16-1.72]) or severe (1.40 [1.11-1.76]), and smoking (1.62 [1.31-2.00]). Sleep difficulty and low sleep quantity were not associated with age, alcohol consumption, or timing of worst itch.

CONCLUSION

These results are potentially meaningful in several aspects. We identify an important distinction between sleep difficulty and sleep quantity in psoriatic disease, whereby having psoriatic arthritis and being female are each associated with sleep difficulty despite no association with low sleep quantity. Furthermore, there is conflicting evidence from prior studies as to whether psoriasis severity is associated with sleep difficulty, but this well-powered, large study revealed a strong, graded relationship between psoriasis severity and both sleep difficulty and low sleep quantity. Overall, our results show that both sleep difficulty and low sleep quantity were associated with multiple factors in this analysis of a large psoriatic cohort. These findings suggest that dermatologists may gather clinically useful information by screening psoriatic patients for trouble sleeping and low sleep quantity to identify potential comorbidities and to more effectively guide disease management.

Sleep disturbance in psoriasis: a case-controlled study

BACKGROUND

Sleep is essential for daytime functioning and health. Given the physical symptoms of psoriasis, a higher prevalence of sleep disorders can be expected. So far, the studies examining sleep disturbance in psoriasis have been of less-than-optimal methodological quality and with mixed results.

OBJECTIVES

To examine the prevalence of sleep disturbance in patients with plaque psoriasis compared with a control group, to evaluate associations with health-related quality of life (HRQoL) and examine possible disease-related predictors of disturbed sleep.

METHODS

We used a cross-sectional, case-controlled design. Participants included 179 consecutively recruited patients with plaque psoriasis and 105 controls. Measures included psoriasis severity (Psoriasis Area and Severity Index); HRQoL (Dermatology Life Quality Index); insomnia severity [Insomnia Severity Index (ISI)]; sleep quality [Pittsburgh Sleep Quality Index (PSQI)]; stress (Perceived Stress Scale); itch (Itch Severity Scale); and depressive symptoms (Beck Depression Inventory). Analyses included group comparisons and regression analyses to identify predictors of sleep disturbance.

RESULTS

A total of 25% of patients with psoriasis reported clinical insomnia (ISI > 15), compared with 10·5% of controls. In all, 53·6% of patients with psoriasis were poor sleepers (PSQI > 5), compared with 21·9% of controls. Itch was statistically significantly associated with all sleep-related outcomes.

CONCLUSIONS

A higher proportion of patients with psoriasis experience poor sleep than controls from the general population. Itch was the main predictor of impaired sleep. Improved control of psoriasis with decreased itch may improve sleep disturbance in psoriasis.

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. While several sleep investigations have been conducted in psoriasis populations, many have methodological shortcomings, and no study has examined multiple dimensions of sleep-wake functioning. Moreover, research has yet to be performed comprehensively examining the range of physical and psychological factors that may affect sleep in people with psoriasis.

OBJECTIVES

To characterize sleep disturbance using validated measures and to identify physical and psychological predictors of sleep quality in people with psoriasis.

METHODS

An online survey was conducted (186 respondents; mean age 39·2 years) 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

The mean PSQI score was 9·2 ± 4·3, with 76·3% scoring above the threshold for poor sleep (≥ 6 on the PSQI) and 32·5% scoring 'positive' for probable obstructive sleep apnoea (OSA). Poor sleep and high likelihood of OSA were associated with more severe psoriasis (P < 0·05; η = 0·07; η² = 0·005). Cognitive arousal (β = 0·26, P = 0·001), itch (β = 0·26, P < 0·001) and depression (β = 0·24, P = 0·001) were the most robust predictors of poor sleep quality, which, together with somatic arousal (β = 0·17, P = 0·022), 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 OSA are also high. Given the importance of restorative sleep for health, sleep complaints should receive greater clinical attention in the management of psoriasis.