FRIDAY, May 20 (HealthDay News) -- People who have psoriasis and hypertension are more likely to have more severe high blood pressure, requiring more medications to control it, a new study suggests.
About 4 percent of the U.S. population has psoriasis, which causes itchy, thickened, dry, red patches on the skin.
Researchers from the University of California, Davis Health System examined 835 patients who had psoriasis and hypertension. Their cases were compared with more than 2,400 people who had hypertension but not psoriasis.
The patients with psoriasis were more likely to need the highest level of blood pressure treatment, which relies on a central-acting agent (also known as adrenergic inhibitors) that's used in people whose high blood pressure can't be controlled with conventional medications.
Hypertensive patients with psoriasis were also nearly 20 times more likely to be on four drugs or on a central-acting agent than hypertensive patients without psoriasis.
The study is published online in PLoS One.
The study's authors noted the findings were significant even after other risk factors associated with hypertension, including diabetes, smoking and high cholesterol, were taken into account. The researchers also pointed out it is unlikely that drugs used to treat psoriasis are responsible for the increased severity of hypertension.
"Our study makes a strong case that psoriasis is not just a skin-deep disease," said lead study author Dr. April W. Armstrong, UC Davis assistant clinical professor of dermatology, in a university news release. "We are beginning to find that psoriasis may represent a window into detecting cardiovascular conditions, including hypertension."
Armstrong added that the findings may alert physicians who treat hypertension, a risk factor for heart disease and stroke. "Hypertensive patients who also have psoriasis are likely to need closer monitoring and a more aggressive drug regimen to achieve adequate blood-pressure control," she said.
Over the past four decades, researchers have developed several theories to explain the link between psoriasis and hypertension, including:
- People with psoriasis may be more likely to develop constricted blood vessels, which increases blood pressure.
- Patients with psoriasis have elevated levels of a protein produced by skin cells (endothelin I), which constricts blood vessels and increases blood pressure.
- As an inflammatory disease, psoriasis can result in damage to blood vessels and the heart.
"Our understanding of psoriasis as a systemic disease is rapidly evolving," concluded Armstrong. "A better appreciation of the other conditions that tend to accompany psoriasis could potentially drive our therapy of the disease in the future."
While the new study found an association between psoriasis and high blood pressure, it did not demonstrate a cause-and-effect.
The U.S. National Institutes of Health offers more detailed information on psoriasis.
SOURCE: UC Davis Health System, news release, May 12, 2011
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