Epidemiology of Psoriasis. A Population-Based Study

Psoriasis is a chronic immunoinflammatory skin disease very frequent in the western world. Several authors have tried to calculate its prevalence in different regions, although most of them obtained the data from surveys and there are few publications from Mediterranean areas. The objective of our study was to analyze the prevalence and severity of psoriasis in Lleida (a northeastern region in Spain), identify age and sex specific differences and compare our results with other European series.

A joint database of primary care medicine and the dermatology department was obtained from the entire province of Lleida with epidemiological data and psoriasis diagnosis and treatment codification.

A corrected database was obtained with 398,701 individuals and 6,868 of them (1.72%) were coded with the diagnosis of psoriasis. The prevalence was significantly higher in men than in women (1.88% vs 1.56%, OR=1.21, 95% CI: 1.15-1.27). The highest prevalence of psoriasis was found in the 61-70 years group (2.90%) and psoriasis in population under 18 years of age was 0.30%. In our sample, 7.27% of the patients were classified as moderate-severe psoriasis (499/6,868).

This study reports the prevalence and severity of psoriasis in a large Mediterranean region sample, obtaining the information through a electronic database. This study reveals a lower prevalence of psoriasis compared to other European countries, and the proportion of severe psoriasis (based on treatment criteria) is lower than in other studies. We emphasize that these differences could probably due to genetic background, life style and diet.