Poor sleep is a common problem for many patients, affecting approximately one out of three individuals, according to the Center for Disease Control (CDC). Chronic sleep dysfunction is associated with decreased concentration and impaired performance and is also associated with the following comorbid conditions: cardiovascular disease, hypertension, obesity, type 2 diabetes mellitus, and depression.
Chronic sleep dysfunction is divided into insufficient quantity of sleep and poor quality of sleep. Insufficient quantity is easy to assess and is defined as less than 7 hours of sleep per day. On the other hand, assessing sleep quality is far more complex and difficult to assess as sleep quality is measured by sleep latency, continuity, depth, and post-sleep restoration. Assessing sleep quality requires objective evaluation using polysomnography and other specialized methods.
Poor sleep is especially prevalent in patients with psoriasis with almost 90% of psoriasis patients reporting issues sleeping. Sleep dysfunction among psoriasis patients is particularly concerning because psoriasis is independently associated with many of the same comorbid conditions as sleep dysfunction compounding their impact. One study showed that psoriasis patients with sleep disorders had an increased incidence of ischemic heart disease and strokes.
In order to investigate chronic sleep dysfunction prevalence in psoriasis, Dr. Smith and colleagues from the Department of Dermatology, University of California, San Francisco, used the Citizen Pscientist (CP), an online patient portal developed by the National Psoriasis Foundation (NPF). The CP is an online forum that allows patients with psoriasis to connect with one another. When joining CP psoriatic patients fill out a survey that includes demographic details, symptoms and treatment histories, and quality of life topics such as the impact of their condition on diet, exercise, and of course sleep.
The CP survey was completed by 3118 patients. The CP Survey contained 79 questions of which 15 questions were analyzed. Psoriatic patient sleep characteristics were derived from survey questions about hours of sleep per day on average and trouble sleeping. ‘Low sleep quality’ was defined as patients that report sleeping less than 7 hours per day on average. ‘Sleep difficulty’ was defined as participants that answered “yes” to the question “Do you have trouble sleeping?”
Once survey data was collected two separate multivariate logistic regression models were used to determine whether the presence of psoriatic arthritis, age, gender, body mass index (BMI), comorbid sleep apnea, psoriasis severity, timing of worst itch, smoking status, or high-risk alcohol consumption were lined to sleep dysfunction.
Results showed 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]).
With regards to ‘low sleep quantity’ results showed an association with obesity (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]). Surprisingly ‘sleep difficulty’ and ‘low sleep quantity’ were not associated with age, alcohol consumption, or timing of worst itch.
This was a large study that shows that psoriasis is associated with sleep dysfunction, and that increased psoriatic activity may enhance sleep dysfunction. The study was limited by the CP instrument and patient reported unconfirmed data. It reinforces the need to better understand the role of sleep in psoriasis and vice versa to improve the quality of life of psoriatic patients and to prevent the associated comorbid conditions associated with psoriasis and sleep dysfunction.
Smith, Mary Patricia, et al. "Factors Influencing Sleep Difficulty and Sleep Quantity in the Citizen Pscientist Psoriatic Cohort." Dermatology and therapy (2019): 1-13.