Psoriasis is a chronic inflammatory disease that affects 2-3% of the adult population. Its pathophysiology is characterized by immune responses mediated by type 1 and type 17 helper T lymphocytes and synthesis of various cytokines that produce inflammation of the skin and joints. Other inflammatory markers, such as C-reactive protein, are also increased at the systemic level.1 Proinflammatory mediators are involved in the onset of acute ischemic coronary artery disease (CAD), as in other chronic inflammatory diseases, such as rheumatoid arthritis or lupus erythematosus.2 The European Guidelines on cardiovascular disease prevention recently included psoriasis as a risk factor for ischemic heart disease.3

Although an association between psoriasis and acute ischemic CAD has been found in various populations,4 data for patients in the Mediterranean area are lacking, and differential characteristics for cardiovascular risk in this population have not been investigated. We designed a cross-sectional study to evaluate the association between psoriasis and risk of ischemic CAD in the province of Castellón, Spain.

The control population comprised patients with benign skin disease not caused by inflammatory processes, such as melanocytic nevus. The presence of nevus in all age groups and the absence of an association with inflammation enabled us to use these patients as a control group.

The objective of the study was to determine the prevalence of ischemic CAD in patients with psoriasis in our geographic area and to compare it with the prevalence of ischemic CAD in patients with melanocytic nevus.

Several studies have investigated the association between psoriasis and cardiovascular disease based on inflammatory mechanisms that are common to both diseases. The results of the studies are very different, and an association was found between the diseases in some7–10 but not in others.2,11 In their review of the association between psoriasis and cardiovascular disease, Dauden et al.4 examined 15 studies from the last decade in the United Kingdom, Germany, United States, Taiwan, and Israel. These studies revealed a greater risk among patients with psoriasis.4 Studies that evaluate cardiovascular risk cannot be directly extrapolated from one European country to another. Significant differences have been found in the incidence of ischemic CAD between European countries; therefore, it has been proposed that cardiovascular risk should be evaluated taking into account the relevant geographic area.12,13 In Spain, the various studies on psoriasis and cardiovascular risk were performed among hospital patients; therefore, no results are available for the general population.14

A meta-analysis of published studies revealed an association between psoriasis and cardiovascular disease, as well as between psoriasis and other cardiovascular risk factors. However, these associations disappear in studies from population databases.14 Unlike other studies,14,15 ours is not subject to bias stemming from the selection of hospital patients only, since it includes both hospital patients and outpatients seen by dermatologists and cardiologists or family physicians; therefore, it includes mild, moderate, and severe psoriasis in the same proportion as in the general population. This is possible because of the characteristics of our health system, which provides almost universal care. The age- and sex-adjusted multivariate analysis showed that psoriasis is an independent cardiovascular risk factor. The presence of an association between ischemic CAD and any type of psoriasis (whether extensive or not) confirms psoriasis as an independent cardiovascular risk factor, although this does not rule out the possibility that risk could increase with severity. Given that 2% to 3% of the Spanish population have psoriasis (80% mild and 20% moderate to severe),16 the number of patients potentially exposed to this risk factor is high. According to European guidelines on cardiovascular disease prevention,3 this observation would support prevention of cardiovascular disease from an early age, and more so in persons with risk factors such as psoriasis. Other unanswered questions requiring different types of study include whether a patient with psoriasis could benefit from primary prevention with drugs to treat ischemic CAD or whether more aggressive treatment of psoriasis would reduce cardiovascular risk.

An association between psoriasis and other cardiovascular risk factors such as hypertension, diabetes mellitus, dyslipidemia, and obesity has been reported in several countries.7,8,10,16 In our setting, where the presence of cardiovascular risk factors is greater in psoriatic patients, the fact that the population traditionally follows a Mediterranean diet, lives in small towns, enjoys universal health care, and is scarcely affected by the disadvantages typical of an urban lifestyle (eg, type of diet, frequent use of cars) leads us to ask, as did Gelfland et al.,10 whether psoriasis and ischemic CAD are not only associated with inflammation, but whether they are also the product of factors such as stress, a sedentary lifestyle, or low control of cardiovascular risks. Parodi et al.17 recently carried out a study in a Mediterranean population in Italy in which they found an association between psoriasis and other cardiovascular risk factors, although the study sample did comprise hospital patients. Population studies are necessary to determine whether psoriasis is associated with other cardiovascular risk factors.

The lack of an association between ischemic CAD and smoking in the present study is due to coding bias. Until recently, smoking was only routinely coded in the database when patients requested help with cessation. Although smoking is now recorded and coded at the primary care visit, our data were collected before this change was made.

The present study could be limited by the fact that diagnostic error cannot be ruled out during coding; however, we feel this possibility is minimal owing to the size of our database. Coding of ischemic heart disease is usually best recorded in the clinical history taken by the family physician because of its implications for prognosis and treatment. Furthermore, ours is a population-based, cross-sectional study with the methodological limitations inherent to its design, namely, it is not possible to establish the time sequence between ischemic CAD and psoriasis, and what we call risk factors could also be factors associated with more chronic disease or greater survival. Similarly, we do not distinguish between degrees of psoriasis. The diagnosis of psoriasis was taken as categorical, since we were interested in considering psoriasis as a risk factor. We excluded cases with concomitant diagnoses of psoriasis and nevus to differentiate clearly between the control group and the study group. We felt that the minimum bias this could cause was less important than the potential confusion of including it in the study.

Our results point to an increased risk of ischemic CAD in patients with psoriasis in the Mediterranean area. Further studies would be necessary to determine whether treatment of psoriasis or primary prevention based on drug therapy would reduce this risk.

The authors declare that they have no conflicts of interest.