**1. Introduction**

Psoriasis is a chronic, inflammatory, genetically determined skin condition, with a frequency of 1–3% in the general population [1]. The onset of the disease frequently occurs around the age of 20 or around the age of 40, and the negative consequences of psoriasis should be emphasized: in young people at the beginning of their careers it often leads to their underestimation, and in working adults it often leads to premature retirement. Among the dermatological conditions, psoriasis takes the first place in terms of deterioration of life quality index, ahead of malignant skin diseases. Psoriasis impairment to psychological quality of life is comparable to cancer, myocardial infarction, and depression [2]. Psoriasis therefore has a debilitating influence both physically and mentally on the patient's daily life. Standard diagnostic criteria for epidemiological studies of psoriasis are currently lacking. In their absence, clinical examination and diagnosis of psoriasis by dermatologists provides the gold standard to underpin epidemiological research in psoriasis [3].

Psoriasis has been declared by the World Health Organization the fifth most important chronic non-contagious disease, along with diseases such as diabetes, cancer, cardiovascular

**Citation:** Nicolescu, A.C.; Bucur, S, .; Giurc ˘aneanu, C.; Gheuc ˘a-Solov ˘astru, L.; Constantin, T.; Furtunescu, F.; Ancut ,a, I.; Constantin, M.M. Prevalence and Characteristics of Psoriasis in Romania—First Study in Overall Population. *J. Pers. Med.* **2021**, *11*, 523. https://doi.org/10.3390/ jpm11060523

Academic Editor: Mircea Tampa

Received: 10 May 2021 Accepted: 5 June 2021 Published: 7 June 2021

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or respiratory diseases. Statistics show that there are over 125 million patients in the world and Romania ranks first in Europe, having approximately 400,000 people with this condition [4]. A total of 20–30% of patients with psoriasis also develop psoriatic arthritis, which over time leads to severe, deforming joint injuries, which often cause disability [5]. In the absence of a set of specific criteria for the diagnosis of psoriatic arthritis, the most commonly used method for recognizing and monitoring this condition remains the clinical aspect [6].

In Romania, psoriasis remains a common, immune-mediated disease, with increasing prevalence. This publication quantifies the prevalence of psoriasis in Romania, its potentially genetic background, and the importance of environmental factors in triggering it [7], including the role of the diet [8,9] and other factors, such as vitamin D deficiency [10].

Psoriatic subjects represent an important target for health care issues and further epidemiological studies. The estimates provided can help guide countries and the international community when making public health decisions on the appropriate management of psoriasis.

#### **2. Objectives**

It is thought that there are more undiagnosed or untreated patients beyond those who have been diagnosed. This study aims to develop and validate a screening questionnaire for the early, presumptive identification of psoriasis in the general population and to estimate the prevalence of people suffering from this condition at a national level.

In order to achieve the objectives, quantitative research was conducted at a national level among the general adult population (people over 18 years old in urban and rural areas in Romania).

#### **3. Materials and Methods**

The study was performed in two stages. Stage 1 involved the development of the questionnaire and construction of the predictive model. Within this stage, the questionnaire was developed by a mixed team of experts (dermatologists, epidemiologists, sociologists), the methodology was finalized, and standardized working procedures were developed.

Stage 2 involved the validation of the questionnaire and the estimation of the national prevalence. At this stage, a national study was conducted on a representative sample of 1500 adult individuals. From this total of 1500 people to whom the questionnaire was applied, a subgroup of 500 people was randomly selected and received in addition a clinical examination aiming to diagnose the eventual presence of psoriasis.

Detailed description of the study.

The first stage of the study was conducted between November 2018–February 2019, on two groups of subjects: the group with psoriasis (288 patients with psoriasis selected from the offices of dermatologists from all over the country) and the control group (222 healthy people randomly selected from the general population). The inclusion criteria were: adults over 18 years old, from rural and urban areas in Romania, without a diagnosis of psoriasis (healthy group); or those with a previous diagnosis of psoriasis (affected group). The only exclusion criterion was represented by institutionalized persons. Both groups received a questionnaire applied through face-to-face interviews and underwent parallel dermatologic examination.

The questionnaire included three sections: (i) a general part referring to demographic characteristics; (ii) a screening part with specific questions regarding the existence of symptoms and the history of dermatological diseases; (iii) a section of a detailed characterization of the person from a social and clinical point of view. During this first stage, both the research tool (questionnaire) and the logistical organization and field activity management tools were tested. This activity was carried out by field operators with experience in conducting household surveys.

A predictive model has been elaborated by performing a logistic regression applied to the pilot data. The discriminative variables were: (1) the symptoms of psoriasis (presence

and nature of skin and nail lesions, including the occurrence of stress for all forms of psoriasis) and the symptoms and signs of arthritis for the arthropathic form; (2) the presence of hereditary collateral antecedents; (3) smoking at the time of the study; (4) history of pharyngitis in childhood for the presence of arthropathy; (5) history of obesity, but not obesity at the time of the study; (6) depression due to the arthropathic nature of psoriasis; (7) treatment; (8) some psycho-emotional and contextual characteristics. The proposed questionnaire was reviewed and updated according to the relevant variables.

The second stage of the study was conducted in 2019 on a group of 1500 respondents over the age of 18 on a nationally representative group. The national study used a three-stage stratified probabilistic grouping model. The questionnaire was applied in a "face-to-face" interview by specialized interview operators. A total of 500 randomly selected individuals from this group underwent clinical examination performed by a dermatologist at the nearest medical unit to the home of the person included in the group. The application of the questionnaire at the same time with the performance of clinical examinations allowed the validation of the questionnaire and the establishment of its specific parameters (sensitivity, specificity, accuracy, predictive value).

In a further step, the prevalence of psoriasis was estimated at the national level.

The national sample selection used a stratified three-step probabilistic grouping pattern in which places were selected with PPS (probability proportional to size) in the first step. Households were systematically selected in the second step and only one individual from each household was selected by SRS (simple random sample) using mobile data collection devices. The first step consisted in the selection of localities (stratification was performed according to the environment of residence (urban or rural) and type of urban/rural locality: in urban areas, stratification was performed by size of locality: small town (less than 50,000 inhabitants), medium town (50,000–199,999 inhabitants) and large city (over 200,000 inhabitants). In rural areas, the stratification was carried out taking into account two types of rural localities: localities with up to 5000 inhabitants and localities with over 5000 inhabitants, depending on the number of questionnaires required, the sampling points were calculated for each locality. In the following step, starting from the selected group points, the systematic selection of households that were included in the research was performed. Prior to this stage, the households were identified and included in a list from which the selection of those that were part of the group was made (mapping and listing). In the last step, 1500 individuals were randomly selected.

The interviews were conducted with people over the age of 18 who actually lived at the address selected from the group. In each identified household, the questionnaire was applied to one person. If there were several eligible persons in the household (more than two over the age of 18) the questionnaire was applied to one person who was randomly selected. If the selected person was not at home at the time of the first visit and was absent for less than 30 days (the person was at work, on a delegation, on holiday etc.), a new visit to the household was scheduled. In this regard, at least three attempts (visits) were made to interview the selected person. The validation of the group was performed according to the official statistical data provided by the National Institute of Statistics [11].

Within the project, a software application was developed that allowed both data collection and management of the activity of conducting clinical examinations at a national level. The application was a client server type. The samples and the collected data were stored in the server component both after applying the questionnaire and as a result of clinical examinations. The clients of the application were represented by the face-to-face interview operators and by the doctors involved in performing the clinical examinations.

The coordination, monitoring, and supervision of the field activity were carried out by a field coordinator with experience. The activity which involved data collection at a local level was coordinated and supervised by the county coordinators, the data collection being ensured by a specialized network of interview operators. Dermatologists and nurses were recruited to perform clinical examinations from the dermatology medical offices who expressed their acceptance to participate in the study. After performing the clinical examinations, the specialists sent the results to the headquarters according to the established working procedures.

The statistical analysis was performed with the R system. Mean ± standard deviation and/or median have been calculated for the scale variables and proportions for the qualitative ones. Comparisons were performed using the *t*-test and ANOVA for quantitative research, normally distributed variables and the chi-square or Fisher test for qualitative. The logistic regression has been used to construct the predictive model. Sensitivity and specificity have been calculated for the questionnaire in relation to the gold standard dermatological diagnosis for psoriasis. A 95% confidence interval was calculated for the psoriasis prevalence in general population.

The demographic profile included: gender, age group, level of education, occupation, residence environment (urban, rural), region of economic development (Northeast, Southeast, South, Southwest, West, Northwest, Center, Bucharest). The clinical profile and personal medical history of the respondents included details on symptoms, frequency of symptoms, determining factors, associated conditions, previous diagnosis of dermatological disease, the age of onset of symptoms, personal medical history. The use of medical services for dermatological diseases was analyzed in terms of the following characteristics: previous treatments for dermatological conditions and their type, specific clinical examinations performed, accessed services.

The diagnosis in psoriasis for the subjects performing the dermatological examination was a clinical one (observation of erythematous and squamous patches, generalized or localized in specific areas, itching, burning or soreness, thickened, pitted or ridged nails, swollen and stiff joints). During the medical consultation, personal and family history and risk factors were also evaluated. A subgroup of 500 people randomly selected were invited to participate in a specialized clinical examination performed by a dermatologist in a medical office in order to analyze the association between the questionnaire and the real status of the subjects and to explore the validity and prediction of the questionnaire. The subgroup had similar geographic and demographic characteristics and similar history of the disease (Table 1).


**Table 1.** Comparative analysis of the groups according to the main demographic variables in stage 2 of the study.


**Table 1.** *Cont.*

**\*** Test Chi<sup>2</sup> .

Selected subjects were asked to give their consent for the examination. From the 500 selected subjects, 18 did not agree to participate to the clinical examination and another 21 agreed, but did not show up at the dermatologist. The study algorithm is shown in Figure 1.

**Figure 1.** The study algorithm.

The diagnosis in psoriasis was a clinical one (observation of erythematous and squamous patches, generalized or localized in specific areas, itching, burning or soreness, thickened, pitted or ridged nails, swollen and stiff joints). During the medical consultation personal and family history and risk factors were also evaluated.
