The evidence linking psoriasis to metabolic syndrome and cardiovascular disease is overwhelming, classifying psoriasis as a systemic disease and not simply a disease of the skin.
According to experts, dermatologists must not only treat the cutaneous manifestations of psoriasis, but also address the comorbidities that are associated with it.
Metabolic syndrome consists of four major components: type II diabetes, hypertension, dyslipidemia and obesity. All are associated with an increased cardiovascular risk.
The new conventional wisdom is that psoriasis, metabolic syndrome and cardiovascular disease are linked to one another, and the one common denominator they appear to share is inflammation.
Interestingly, psoriasis patients with concomitant metabolic syndrome have a higher risk for these inflammatory cytokines, because the fat that is associated with metabolic syndrome is metabolically active, meaning it also produces these inflammatory cytokines. Therefore, patients with psoriasis can have two pathways of chronic inflammation - from the skin as well as from the fat - both routes resulting in a systemic inflammatory effect.
"The understanding of psoriasis has rapidly evolved over the last five years from primarily being thought of as a skin disease, with approximately 25 percent of patients also suffering from psoriatic arthritis, to a potentially serious and systemic inflammatory disease. The true nature of psoriasis is becoming more elucidated as new study data emerges," says Frank J. Dann, M.D., department of dermatology, Long Beach Veterans Affairs Medical Center, Long Beach, Calif.
Paolo Gisondi M.D., department of dermatology, Borgo Trento Hospital, Verona, Italy, recently conducted a hospital-based, case-controlled study looking at the prevalence of metabolic syndrome in 338 adult chronic plaque psoriasis patients compared to 334 patients with skin diseases other than psoriasis.
He found that the prevalence of metabolic syndrome was higher in psoriatic patients compared to controls (30.1 percent versus 20.6 percent), and that psoriatic patients with metabolic syndrome were older and had a longer disease duration, compared with psoriatic patients without metabolic syndrome. Additionally, waist circumference was higher in the psoriasis group.
"The presence of metabolic syndrome in psoriasis patients is a negative predictor of cardiovascular mortality," Dr. Gisondi says.
Other evidence showing psoriasis to be a systemic disease is seen in work from Joel Gelfand, M.D., medical director, Clinical Studies Unit, assistant professor of dermatology and associate scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia. It was found that psoriasis patients have a higher risk of myocardial infarction - with severe psoriasis patients showing a higher risk of mortality by five years, even when comorbidities such diabetes, obesity and smoking are corrected for.
Interestingly, both Dr. Gisondi's and Dr. Gelfand's research showed that psoriasis patients have a higher risk of comorbid conditions, whether they have features of metabolic syndrome or not. However, obesity appears to play a center role in the myriad comorbidities.