Evaluation of sleep quality and pruritus severity in psoriatic patients and their impact on quality of life: a cross section correlational study

Psoriasis is a chronic inflammatory condition associated with genetic and immunological susceptibility. The objective of the study was to evaluate pruritus and sleep quality in correlation (r) to psoriasis severity and to detect their impact on quality of life. Two hundred (200) patients with psoriasis were included. Psoriasis severity was determined using the psoriasis area severity index (PASI), the quality of life (QoL) was assessed by the psoriasis disability index (PDI) questionnaire, and the sleep quality was evaluated by the Pittsburgh sleep quality index (PSQI). Finally, the severity of itching was evaluated using a 12-item pruritus severity scale (PSS). Poor sleep quality was found in 16.0% of patients in this study. Poor sleep was detected among 50.0% of cases with severe psoriasis. PASI scores correlated significantly with sleep quality, duration and sleep disturbances (p < 0.001). The global PSQI and PASI were also significantly correlated (p = 0.004). In conclusion patients complaining of psoriasis exacerbated by pruritus and sleep problems demonstrated lower quality of life in all domains. Sleep disturbances and depressive symptoms impairing quality of life should be taken into consideration when screening patients suffering from psoriasis.


PASI Psoriasis area severity index QoL
Quality of life PDI Psoriasis disability index PSQI Pittsburgh sleep quality index PSS Pruritus severity scale Th-1) T-helper cells APCs Antigen presenting cells Psoriasis is a chronic inflammatory skin disease with genetic and immunological background and is exacerbated and triggered by environmental factors 1 .Sleep disturbances (SDs) are experienced by psoriatic patients and affect their quality of life.A close relationship exists between psoriasis and SDs, the pathophysiological mechanisms of which are not fully understood.
Psoriasis is characterized by activation of T-helper cells (Th-1), antigen presenting cells (APCs) and by recruitment of Th-1 cytokines characterized by expansion and activation of T-helper cells (Th-1), antigen presenting cells, and Th-1 cytokines and interleukins.It had been revealed that increased serum levels of inflammatory cytokines such as tumor necrosis factor alpha and interleukin 6 are responsible for sleep restriction in psoriasis 2,3 .Moreover; higher concentration of substance P discovered in perilesional skin of psoriatic patients had been related to disturbed sleep cycles and their regulation 4 .In addition to the above, the lower melatonin

Patients and methods
This study was a cross sectional study that included 200 patients diagnosed clinically with psoriasis that were recruited from the outpatient clinics.Twenty three subjects were excluded earlier due to being on topical or systemic medications at the time of data collection.Following the study's approval by the local ethics committee at the Faculty of Medicine at Al-Azhar University in Damietta (IRB 00012367-21-03-003), all cases included in the study provided their verbal or written informed consent.
Patients were included if they had established psoriasis of more than 6 months and were able to read and write for completing the questionnaire.Exclusion criteria included pregnant or lactating females, other concomitant dermatological or systemic disorders that might cause pruritus such as chronic uremia or cholestasis, and usage of medications that could influence the sensation of itch.Moreover Subjects with cognitive impairment, present psychiatric disorders, active depression, substance use, and smoking as well as those pustular psoriasis and cases with concomitant psoriatic arthritis (PsA) were also excluded.
(4) Any coexistent chronic diseases (diabetes mellitus, hypertension, heart disease, chronic kidney disease, chronic liver disease, thyroid disease, stroke).( 5 (III) Psoriasis grading with Psoriasis Area Severity Index (PASI) PASI score was used for severity and extent assessment of psoriasis.It ranges from zero (no disease) to 72 (severe disease) (maximal disease severity.Scores below 10 mark mild psoriasis and scores above 20 are regarded as severe while scores falling between 10 and 20 are regarded as moderate psoriasis (6).

(IV) Evaluation of Disease-related Quality of Life of the subjects using Arabic version of Psoriasis Disability Index (PDI)
The effect of psoriasis on daily activities, work or school, relationships, leisure, and treatment were assessed using the psoriasis disability index questionnaire (PDI) 7 .The reliability of the Arabic version of the DPI was validated and was found to be reliable for evaluating the QOL for Egyptian patients with psoriasis and was used in the current study 8 .The PDI is made up of 15 simple, disease-related questions.Each question is scored on a scale of 0 to 4, with a maximum score of 45.The lower the score, the lower is the quality of life.The PDI can also be reported as a percentage of a maximum possible score of 45.The overall score indicates how psoriasis has affected the patient over the last four weeks.(V) Evaluation of sleep quality using arabic translation of Pittsburgh sleep quality index (PSQI) Sleep quality was assessed using the Arabic validated version 9 of the PSQI 10 .Seven components are used; subjective sleep quality, latency of sleep, duration of sleeping, habitual sleep efficiency, disturbances of sleep, whether or not sleep medications are used, and dysfunction of the following day over the last month.Each component is scored from 0 to 3, resulting in a global PSQI score between 0 and 21, with higher scores indicating lower quality of sleep.The PSQI score ≥ 5 was considered as a cut-off for poor sleep quality.

Statistical analysis
The data was anonymized and fed to personal computer software statistical package of social sciences (SPSS), version 16 (SPSS Inc., Chicago, USA).Data had been presented by their mean, median, standard deviation, relative frequency and percentages according to its type and normality of distribution.Groups compared by independent samples "t" test, Chi square test or any equivalent according to type of data.Pearson's correlation (r) coefficient was calculated to address possible correlation (r) between variables and p value < 0.05 was set as statistically significant.

Study approval statement
This study protocol was reviewed and approved by ethics committee on human research by Al Azhar Damietta faculty of medicine (No. 00012367-21-03-003).All methods were performed in accordance with the relevant guidelines and regulations.

Consent to participate statement
Written informed consents were received from participants upon explanation of the study.Consent for publication were obtained from the participants for publishing the images in the manuscript.

Results
The mean age of the studied cases was 38.9 ± 17.84 years ranging from 6 to 75 years among which half of them were females.One hundred and fifty six cases (78.0%) were diagnosed as plaque type psoriasis, 32 cases (16.0%) suffered from palmo plantar psoriasis and only 12 (6.0%) of cases had scalp psoriasis.The median disease duration was 7.3 ± 6.2 years and ranged from 1 to 30 years.The median PASI score was 5.6 and ranged from 0.5 to 22.8.Of the studied cases; 76% had mild PASI, 20.0% demonstrated moderate PASI and only 4.0% presented with severe PASI.The pruritus severity scale ranged from 3 to 20 with a median score of 9; with 34.0% of cases presenting with mild pruritus, 32.0% with moderate pruritus and 34.0% with severe pruritus.Psoriasis disability index ranged from 0 to 26 with a median score of 5. Poor sleep quality was found in 16.0% of patients in this study (Tables 1, 2).
Among all sleep quality domains, a statistically significant relation was established between sleep efficiency and the type of psoriasis (p = 0.036).A sleep efficiency score of 0 was detected among 56.2% of cases with palmoplantar psoriasis versus 78.2% of cases with plaque type psoriasis and 83.3% of cases with scalp psoriasis.Scores of 2 and 3 among the efficiency domain was only detectable among cases with plaque type psoriasis when compared to subjects with palmpolantar psoriasis or scalp psoriasis.Sleeping efficiency was significantly lower among subjects with plaque type psoriasis when compared to the other two groups (p = 0.036).The median disease duration among cases with poor sleep was higher than cases with good sleep (10 years vs. 6.5 years; p = 0.039).Longer disease duration was associated with significantly lower quality of sleep in all domains (Tables 3, 4).disturbance and daytime dysfunction had significant correlation (r)s with PASI (p < 0.001).The global PSQI and PASI were also significantly correlated (p = 0.004).Cases with severe pruritus were associated with higher incidence of sleep disturbance in all domains (p < 0.001).The global PSQI and pruritus severity were also significantly correlated (p < 0.001).A median higher psoriasis disability index percent was associated with poor sleep than cases with good sleep (20.5% vs. 4.0%).The lower global PSQI was significantly associated with more psoriasis disability (p < 0.001) (Tables 5, 6, 7, 8).

Discussion
The current study showed that 16.0% of psoriatic subjects included reported poor sleep quality.Moreover; we determined a significant impact of psoriasis severity and pruritus on the disability index and quality of sleep.Different studies investigated the reciprocal effect of sleep impairment and its relation to psoriasis or its severity using different assessment tools such as the PSQI, the Functional Outcomes of Sleep Questionnaire (FOSQ), the General Sleep Disturbance Scale (GSDC) and the general health questionnaire (GHQ-H)  (Table 11).
Sleep disturbances (SDs) were found to be higher among patients with psoriatic arthritis (45.1%) when compared to patients with psoriasis (16.0%) 29 .The current study confirmed previous reports demonstrating that psoriasis severity is associated with increased risk of having sleep disturbances (SDs) 20,24,36 .Melikoglu found out that in 48 recruited patients of psoriasis PSQI and SDs significantly correlated with PASI scores (p = 0.03) 24 .
Samaci et al. and Khalaf et al. recruited 60 and 100 patients complaining of psoriasis with a mean PASI score of (10.1 ± 9.7) and (4.97 ± 5.24) respectively.On the contrary to our results, both authors did not find any correlation (r) between either PASI severity or psoriasis duration and the degree of sleep affection 12,35 .The small percentage  www.nature.com/scientificreports/without pruritus.Pruritus intensity correlated with PASI severity and cases with severe pruritus were associated with higher incidence of sleep disturbance in all domains (p < 0.001).Studies determined that psoriatic patients complaining of pruritus show difficulty in falling asleep and have an increased frequency of sleep fragmentation and nocturnal awakening 16,37 .Meanwhile it was established that good sleep significantly reduces the intensity of itching related to psoriasis 33,38,39 .In the current study patients with higher psoriasis disability index (PDI) had significantly diminished components of all sleep components and daytime dysfunction than those patients with lower score of PDI (p < 0.001).We also observed that total PDI was significantly higher among those subjects with moderate to severe psoriasis when compared to those with mild psoriasis (9.5 vs. 4.0, p < 0.001).Severity of psoriasis had been linked to impaired Quality of life (QoL) in a number of studies 22,40 .

Table 2 .
Distribution of sleep quality scores among studied cases.PSQI Pittsburgh sleep quality index, n number, % percentage.

Table 3 .
32lation between psoriasis type and sleep quality in studied cases.MC Monte Carlo test, PSQI Pittsburgh sleep quality index, n number, % percentage.*Statisticallysignificant.Moreover, 20.3% (n = 60) woke up during sleep almost every night, and a further 33.6%(n=99) reported such problem sporadically33.A study by Nowowiejska et al. reported poor sleep quality, was noticed in 47 patients (78.3%), 24 patients (40.0%) subjectively assessed their sleep quality as fairly bad or bad32.Pruritus is characterized by uncomfortable burning sensation, numbness or even pain.Psoriatic patients with prutiris experienced less sleep quality and more sleep disturbances and daytime dysfunction than those patients Vol:.(1234567890) Scientific Reports | (2023) 13:17541 | https://doi.org/10.1038/s41598-023-44757-5www.nature.com/scientificreports/ of poor sleep quality in the current research could be explained by the fact that mild disease was reported in the majority of our patients.Nevertheless; we detected a significant (p-value = 0.008) positive correlation (r) (r = 0.37) between sleep disturbances and PASI severity.Jaworecka et al. demonstrated that 39.3% (n = 116) of patients reported occasional difficulties in falling asleep, and 22.7% of them (n = 67) had such problems almost every day.

Table 4 .
Relation between psoriasis duration and sleep quality in studied cases.KW Kruskal Wallis test, Z Mann Whitney U test, PSQI Pittsburgh sleep quality index.*Statistically significant.

Table 5 .
Relation between PASI score and sleep quality in studied cases.MC Monte Carlo test, PSQI Pittsburgh sleep quality index, PASI psoriasis area severity index, n number, % percentage.*Statistically significant.

Table 6 .
Relation between PSS score and sleep quality in studied cases.MC Monte Carlo test, PSQI Pittsburgh sleep quality index, PSS Pruritus severity score, n number, % percentage.*Statistically significant.

Table 8 .
Factors affecting sleep quality in studied cases.MC Monte Carlo test, MC Monte Carlo test, χ 2 Chisquare test, Z Mann Whitney U test, PASI psoriasis area severity index, n number, % percentage.*Statistically significant.

Table 9 .
Predictors of poor sleep in studied cases.PASI psoriasis area severity index, PSS Pruritus severity score, PDI Psoriasi disability index, CI confidence interval, β regression coefficient.*Statistically significant.

Table 10 .
Linear regression for prediction of global sleep score.PASI psoriasis area severity index, PSS pruritus severity score, PDI psoriasi disability index, β regression coefficient, t t test.*Statistically significant.

Table 11 .
Prevalence of sleep disorders (SDs) among psoriatic patients in different studies.PSQI Pittsburgh sleep quality index, GSDS general sleep disturbance scale, GHQ-H general health questionnaire, DLQI dermatology life quality index (DLQI).