By Anne Harding

NEW YORK - People with severe forms of the inflammatory skin disease psoriasis are more likely to die of heart-related causes and stroke than those without the condition, new research shows.

In fact, for people with the severe form of psoriasis, the condition is a bigger risk factor for heart- and stroke-related death than high blood pressure, Dr. Joel M. Gelfand of the University of Pennsylvania School of Medicine in Philadelphia, one of the researchers on the study, told Reuters Health.

The findings "should be a very strong message" for people with severe psoriasis to get other risk factors like high blood pressure, high cholesterol, and excess weight under control, Gelfand said.

In psoriasis, cells build up on the skin surface and form itchy and sometimes painful scales and red patches. Joint inflammation may also occur. Up to one in 25 of adults have psoriasis, and about one in five of those have severe disease that warrants treatment with powerful inflammation-suppressing drugs like methotrexate.

Because such drugs carry a high risk of side effects, Gelfand noted, most people with severe psoriasis actually go untreated. "In the last 10 years or so there's been an explosion in new drugs approved for psoriasis," he added. "They're too new to know what their full use will be in the psoriasis population."

Gelfand and his colleagues first reported in 2006 that severe psoriasis upped a person's heart attack risk. The illness has since been linked to an increased risk of stroke.

In the current study, he and his colleagues matched 3,603 patients with severe psoriasis to 14,330 people who were free from the disease and followed them for about three years, on average. Three per cent (108) of those with severe psoriasis died of heart- or stroke-related causes, compared with about two per cent (301) of those without psoriasis.

People with severe psoriasis were nearly 60 per cent more likely to die of causes related to heart disease or stroke than those without the disease, the researchers found.

Even once Gelfand and his team accounted for smoking, high blood pressure, and diabetes, the psoriasis patients' risk of death due to these causes was still 57 per cent higher, suggesting that the skin disease in and of itself was the link.

This meant that there was one extra death per 283 people with severe forms of psoriasis per year, compared to those without the disease.

The relationship among factors that increase heart and blood vessel disease risk and psoriasis is very complex, Gelfand noted; for example, smoking and obesity both boost psoriasis risk, while people with psoriasis are known to be more likely to develop diabetes, which in turn ups heart disease risk.

Genes that make people susceptible to psoriasis have been linked to heart disease as well, he added, and the type of inflammation associated with heart- and stroke-related disease is very similar to that involved in psoriasis.

Teasing out the reasons for the link, and figuring out whether treating psoriasis could reduce heart disease risk, will require more research, he and his colleagues conclude.

SOURCE: European Heart Journal, online December 27, 2009.