Psoriasis is a multifactorial chronic inflammatory disease which leads to the serious medical and social problem and in the development of disease thegenetic, immunological and environmental factors have significant importance [1-3].

The 4—7% of world population affected by psoriasis and prevalence of disease steadily grows [4—6]. In approximately 30% of cases, the joint system is parallel included in the process (psoriatic arthritis, spondyroarthritis etc.) due to of which shows significant influence on the QOL of patients [7].

Psoriasis is often combined with number of severe pathologies such as metabolic syndrome, cardiovascular diseases, depressions, diabetes leading to the complication of the treatment course and the healing process makes refracted [8].

Psoriasis shows severe physical, social and psychological impact on the patients and their relative sand changes the QOL patient’s life (especially when the process located on the open areas of the skin it leads to the impossibility of social communication, work difficulties etc.). The patient’s self-esteem steadily decreases, they become shy and their mental health is disturbed [9, 10].

Among the patients with psoriasis many psychosocial disorders, included disadaptation, social phobia and suicide attempts in susceptible to depression people (especially in younger ages and predominantly in case of severe psoriasis) are registered [11, 12].

For the aim of value of affected area, degree of severity of process and CET, the PASI is used and for the evaluation of health-related QOL of patients, the DLQI is used. The correlation between PASI and DLQI is also studied [13-17].

In the SMC of dermatology and STI of Republic of Armenia (Yerevan) in 2015-2018 were surveyed the 132 patients with psoriasis of plaque form of moderate severity were studied, who were divided into 2 groups.

Group I includes the 65 patients from 18 to 64 years old with duration of disease from 0 year to 47 years. The traditional treatment (detoxification, antioxidant, antihistamine, multivitamin, membrane-stabilizing, topical anti-inflammatory therapy during the 1 month) was prescribed to the patients of group I.

Group II includes the 67 patients from 18 to 69 years old with duration of disease from 6 months to 48 years. The alternative treatment (the traditional therapy with the hepatoprotectors - Essential forte) was prescribed to the patients of group II.

The control group (for the determining the reference values of cytokines and comparing the values obtained) includes the practically healthy 18 people from 19 to 57 years old: the periodic donors (9 males and 9 females).

The patients of both I and II groups were divided into 3 subgroups according to following characteristics: by age (up to 45 years old and over 45 years old), by sex (male and female), by duration of disease (up to 10 years and more than 10 years).

For the value of patient's conditions, the PASI (calculated by the accepted methodology and PASI score can make from 0 to 72 points) and DLQI indexes (DLQI score can make from 0 to 30 points) are used [Adaskevich VP, 2014].

For each group of patients the correlation between the PASI-changed and DLQI-changed (CET of psoriasis according to PASI and QOL according to DLQI) and the age, sex and duration of disease is analyzed.

The CET was valued by the decrease of PASI and the QOL — by the DLQI indexes by the following formula: deference of PASI before treatment and after treatment, divided into the PASI before the treatment and multiplied by 100% (PASI (before treatment) — PASI (after treatment)/ PASI (before treatment) * 100% and deference of DLQI before treatment and after treatment, divided into the DLQI before the treatment and multiplied by 100% (DLQI (before treatment) — DLQI (after treatment)/ DLQI (before treatment) * 100% [Adaskevich VP, 2014].

The statistical package SPSS 16.0 was used to perform statistical analysis of data. In particular, the Student’s t-test for independent samples was applied, at that as the test uses a bit different formulas for the cases depending on whether the variances of compared groups are statistically different or not, first the Levene’s test was applied to test variances equality (using F-statistics from Fisher’s distribution). Besides confidence-interval approach was used to test the null hypothesis (means are statistically equal). Significance level considered p≤0,05 [18].

The correlation between patient's age and QOL according to the DLQI score (DLQI-changed) of patients of group I is presented in the table 1 (the descriptive statistics of DLQI-changed is done).

Group I of patients is divided into following age-related 2 subgroups: patients up to 45 years old and over 45 years old. In the 1st subgroup the 34patients and in the 2nd subgroup the 31 patients are included.

The average of 1st subgroup is 56.61 and for 2nd subgroup is 50.22.

The standard deviation of 1st subgroup is 10.700 and for 2nd subgroup is 11.106.

The standard error of 1st subgroup is 1.835 and for 2nd subgroup is 1.995.

As demonstrated, the values of age and DLQI score are correlated in the group I of patients (see also Table 2).

In the Table 2, results of Student's t-test are presented by two lines for 2 independent groups.

In the Table 2 averages of age-related subgroups of patients of group I are compared by Student’s t-test. The table consists of two rows. The first row corresponds to the case when assumed that there is no significant difference between variances of groups (equal variances assumed), while the second row corresponds to the case when assumed that there is significant difference between variances of groups (equal variances not assumed). The hypothesis of equality of variances is tested by Leven’s test by the following two columns: F (Fisher’s statistics) and Sig (the probability of F in the Fisher distribution, when the variances are equal, i.e. reliability of null hypothesis):

It is assumed that if reliability (Sig) is less than 0.05, then hypothesis of equal variances is denied and the second row should be taken into account, otherwise the first row.

In our example (Table 2), the reliability is more than 0.05 (Sig=0.585), so the second row is taken into account.

In the next column is presented Student’s statistic (t), then degree of freedom (df) and then reliability of Student’s statistic (Sig. 2-tailed).

It is accepted that if reliability of Student's statistic) is less than 0.05 then the averages of groups (according to the DLQI-changed) are statistically different.

It has been shown that in the real population, the difference of averages of groups ranges from 1.019 to 11.833.

As is evident in Tabel 1 and Table 2, in the group I of patients, the patient’s age and DLQI score are correlated. In the 1st subgroup (up to 45 years old), the QOL reliably (reliability of Student’s t-test is p = 0.021) and statistically is higher than that of 2nd subgroup (more than 45 years old), correspondingly 56.65 and 50.22.

Below (Figure 1),

The correlation between patient's sex and QOL according to the DLQI score (DLQI-changed) of patients of group II is presented in the Table 3 (the descriptive statistics of DLQI-changed is done).

Group II of patients is divided into 2 subgroups: female (37 patients) and male (30 patients).

The average of 1st subgroup is 74.093 and for 2nd subgroup is 78.346.

The standard deviation of 1st subgroup is 5.6534 and for 2nd subgroup is 5.2044.

The standard error of 1st subgroup is 0.9294 and for 2nd subgroup is 0.9502.

As is evident, there is a correlation between patient's sex and DLQI score in the group II of patients (see also Table 4).

In the Table 4 (see bellow), the results of Student's t-test are presented by two rows for 2 independent groups.

In case of comparison of group’s variances, the reliability of Levene’s test is 0.765 (more than 0.05), so the variances are not statistically different and the first row should be taken into account.

Comparison of averages of groups shows that reliability of t-statistics is less than 0.05 (0.002), so the averages arestatistically different.

It has been shown that in the real population, the difference of averages of groups ranges from –6.9313 to –1.5756.

So, in the group II of patients, the patient’s sex and DLQI score are correlated. In the female’s subgroup, the QOL reliably (reliability of Student’s t-test is p=0.002) is lower than that of male’s subgroup (correspondingly 74.09and 78.35).

Below (Figure 2),

The correlation between patient's age and CET according to the PASI score (PASI-changed) of patients of group II is presented in the Table 5 (the descriptive statistics of PASI-changed is done).

Group II of patients is divided into following age-related 2 subgroups: patients up to 45 years old and over 45 years old. In the 1st subgroup the 38patients and in the 2nd subgroup the 29 patients are included.

The average of 1st subgroup is 88.24 and for 2nd subgroup is 85.238.

The standard deviation of 1st subgroup is 3.7958% and for 2nd subgroup is 7.7489%.

The standard error of 1st subgroup is 0.6158 and for 2nd subgroup is 1.4389.

So, there is a correlation between patient's age and PASI score in the group II of patients (see also Table 6).

In the Table 6, the results of Student's t-test are presented by two rows for 2 independent groups.

In case of comparison of group’s variances, the reliability of Levene’s test is 0.001 (less than 0.05), so the variances are statistically different and the second row should be taken into account.

It has been shown that in the real population, the difference of averages of groups ranges from 0.3178 to 6.6535 interval.

So, in the group II of patients, the patient’s age and PASI-changed are correlated. Among patients up to 45 years old, the CET reliably (reliability of Student’s t-test is p=0.032) is higer then among patients more than 45 years old, correspondingly 88.724 and 85.238.

Below (Figure 3),

The correlation between duration of disease and CET according to the PASI score (PASI-changed) of patients of group II is presented in the Table 7, the descriptive statistics of PASI-changed is done).

Group II of patients is divided into following 2 subgroups: patients up to10 years of duration of disease (35 patients) and more than 10 years duration (32 patients).

The average of 1st subgroup is 88.61 and for 2nd subgroup is 85.687.

The standard deviation of 1st subgroup is 4.8187% and for 2nd subgroup is 6.9134%.

Thestandard error of 1st subgroup is 0.8145 and for 2nd subgroup is 1.2221.

So, there is a correlation between duration of disease and PASI score in the group II of patients (see also Table 8).

In the Table 8, the results of Student's t-test are presented by two rows for 2 independent groups.

In case of comparison ofgroup’s variances, the reliability of Levene’s test is 0.080 (more than 0.05), so the variances are not statistically different and the firts row should be taken into account.

It has been shown that in the real population, the difference of averages of groups ranges from 0.3178 to 6.6535 interval.

Comparison of averages of groups shows that reliability of t-statistics is less than 0.05 (0.047), so the averages arestatistically different.

It has been shown that in the real population, the difference of averages of groups ranges from 0.0381 to 5.8128 interval.

So, in the group II of patients, the duration disease and PASI-changed are correlated. Among patients patients up to 10 years of duration of disease, the CET reliably (reliability of Student's t-test is p=0.032) is higher then among patients more than 10 years of duration of disease, correspondingly 88.612 and 85.687.

Below (The confidence intervals of avarege of PASI-changed by 95% probability according to duration of disease of patients of group II, Figure 4),

Among the 1st subgroup of patients of group I up to 45 years old, the QOL according to the DLQI reliably and statistically is higher then that of patients more than 45 years old (correlation between age and QOL according to the DLQI).

In the group II of patients, the QOL of male patients according to the DLQI is reliably higher than QOL of female patients (correlation between patient's sex and QOL according to the DLQI).

In the group II of patients up to 45 years old, the CET according to the PASI is reliably higher than that of patients more than 45 years old (correlation between age and CET according to the PASI).

In the group II of patients up to 10 years of duration of disease, the CET according to the PASI is reliably higher than in patients of more then 10 years duration of disease.

So the registered data show that the the QOL of psoriasis according to the DLQI is higher in young age period and among males and the CET according to the PASI is also higher among male patients and in case of less then 10 years duration of disease.

Сведения об авторах

Карапетян Ш.В. — https://orcid.org/0000-0003-2162-1423

КАК ЦИТИРОВАТЬ:

Автор, ответственный за переписку: Карапетян Ш.В. —
e-mail: karapetyan.doc@gmail.com