Study Highlights Prevalence of Sleep Disturbances Among Patients with Psoriasis

Sleep disturbances and quality of life impacts are prevalent in those living with psoriasis, new data suggest, and addressing sleep dysfunction may improve disease management and the well-being of patients.1

Zahra Sami—from the Skin Research Center at Shahid Beheshti University of Medical Sciences—led a team of investigators who identified these findings. This case–control study was carried out at 2 tertiary dermatology centres, with Sami et al comparing sleep quality, obstructive sleep apnoea (OSA) risk, and life quality between patients with psoriasis and healthy controls.

“Despite the growing recognition, sleep disturbances remain underdiagnosed in psoriasis patients,” Sami and colleagues wrote.1,2 “We conducted a case–control study at two tertiary dermatology centres to compare sleep quality, obstructive sleep apnoea (OSA) risk and quality of life between psoriasis patients and healthy controls.”

Trial Design and Findings

A prior study informed the sample size calculation, and the investigative team determined that 65 participants were needed per group in their analysis. To enable their subgroup analysis, the team recruited 60 individuals with severe psoriasis, 60 with moderate disease, and 120 healthy controls. Ultimately, they would include data on 119 subjects living with psoriasis and 119 matched controls within their final analysis.

These trial participants were aged 18 - 65 years were recruited from a pair of tertiary dermatology centers and from the Iranian Psoriasis Registry. The control arm of the study consisted of individuals attending the same clinics for cosmetic concerns. Matching was performed based on age as well as sex.

Sami and coauthors highlighted that across the groups, personal characteristics such as marital status and levels of physical activity were similar. All of the study subjects provided written informed consent, and standardized protocols were followed by the investigators to ensure uniform recruitment, assessment, and collection of data via validated instruments, thereby minimizing the risk of missing data.

The severity of psoriasis among these participants was assessed using the Psoriasis Area and Severity Index (PASI), a visual analogue scale (VAS) for itch, and the Dermatology Life Quality Index (DLQI). A variety of validated measures were implemented to assess sleep quality, including:

• The Pittsburgh Sleep Quality Index (PSQI);
• Epworth Sleepiness Scale (ESS);
• Insomnia Severity Index (ISI);
• STOP-BANG questionnaire;
• The International Restless Legs Syndrome Study Group (IRLSSG) criteria.

Overall, those living with psoriasis had significantly poorer sleep quality compared to the control group. Sami and colleagues noted that the mean PSQI scores had been 8.4 ± 3.5 compared to 5.9 ± 3.1 in the control arm (P < .001). Additionally, 81.5% of those in the psoriasis cohort were classified as being poor sleepers. Because of distinctions between groups in terms of BMI and age, the investigative team utilized conditional logistic regression to control for such confounding variables.

After the adjustment, psoriasis was still significantly linked with diminished sleep quality (adjusted odds ratio [OR]: 1.23, 95% CI: 1.13–1.34). The risk of obstructive sleep apnea was also noted by the team as higher among the subjects with psoriasis (adjusted OR: 1.60, 95% CI: 1.26–2.02). While ISI scores were raised in the psoriasis arm, such differences lost statistical significance after the team's adjustment.

Sami and coauthors did not identify significant differences in ESS scores or the prevalence of restless legs syndrome. However, they did find diminished sleep efficiency in the psoriasis cohort (adjusted OR: 0.93, 95% CI: 0.89–0.97, P = .005). They also noted that such patients had increased reports of daytime dysfunction (adjusted OR: 1.26, 95% CI: 1.08–1.45, P = .003).

Among those included in the psoriasis arm of the study, those living with joint involvement reported more pronounced disturbances in their sleep, with the exception of ESS scores. DLQI-evaluated quality of life was shown to be significantly correlated with most sleep-related outcomes (P < .05). Conversely, the coauthors found a lack of meaningful links with severity of pruritus, PASI scores, and duration of their condition.

Sami et al concluded that these data were consistent with prior research, suggesting that sleep disruption in psoriasis may stem from factors such as systemic inflammation, itch, and psychological stress.

“However, our study has limitations, including a relatively small sample size, potential recall bias in self-reports and age/BMI differences between groups, which were statistically adjusted,” they concluded.1 “Additionally, the impact of medications and comorbidities was not fully explored.”

References

1. Sami Z, Pourgholi E, Mozafari N, et al. Psoriasis and sleep disturbances: A case–control study. J Eur Acad Dermatol Venereol. https://doi.org/10.1111/jdv.20869.

2. Saçmacı H, Gürel G. Sleep disorders in patients with psoriasis: a cross-sectional study using non-polysomnographical methods. Sleep Breath. 2019; 23(3): 893–898.