"In patients under age 50 with severe disease, the risk is comparable to diabetes. This is the first study to show this," Joel M. Gelfand, MD, tells WebMD. Gelfand is an assistant professor of dermatology at the University of Pennsylvania School of Medicine.
Gelfand led a team of researchers who compared heart attack risks in almost 131,000 patients with psoriasis; 3,837 of those patients had severe psoriasis. The study also included 556,995 matched patients who did not have psoriasis for comparison.
The researchers found that psoriasis was associated with an elevated risk of heart attack in all age groups, but especially in younger patients with severe disease.
"This is an important finding because psoriasis patients need to be talking to their doctors about this. Likewise, doctors need to be talking to psoriasis patients about this possible risk," says Liz Horn, director of research at the National Psoriasis Foundation.
Gelfand's study appears in the Oct. 11 issue of The Journal of the American Medical Association.
Study Builds on Previous Research
Several smaller, hospital-based studies have shown a link between psoriasis and an increased risk of heart attack. "But none of these studies controlled for age, gender, elevated cholesterol, diabetes, smoking, and other risk factors," Gelfand says. "That's what's novel about our study."
According to the study, excess heart attack risk is higher among psoriasis patients who are younger. For example, a 40-year-old patient with mild disease has a 20% greater risk of heart attack than a 40-year-old patient without psoriasis. But a 40-year-old patient with severe disease has more than double the risk.
The risk appears to decline somewhat in older patients. For example, the study found that a 60-year-old patient with severe disease has a 36% higher risk than a 60-year-old patient without psoriasis.
"The absolute risk is still low, even for someone who has severe disease," Gelfand says. "If you're in your 40s or 50s, your risk of having a heart attack each year due to psoriasis is about one in 400 to one in 600. Over 10 years, that adds up to about one in 40-60. So it does become a significant risk factor over time."
Patient Awareness Low
"Most psoriasis patients are unaware that they have an increased risk of heart attack," Horn tells WebMD. "They just haven't made the connection."
Only in the past year has the National Psoriasis Foundation started addressing the issue in its patient-education materials, she says.
"When something new like this study comes out, we don't want to scare patients," Horn says. "But it's something they need to be aware of, so it's going to be an ongoing challenge for us as a national organization to educate our patient population and for doctors treating these patients."
Studies show that many psoriasis patients already have multiple risk factors for heart disease. "People with psoriasis are more likely to be smokers, be overweight, and have high blood pressure and diabetes ," Gelfand says.
So it's essential that they undergo a medical evaluation for risk factors and receive appropriate treatment for those that can be controlled, Gelfand says.
How Psoriasis Increases the Risk
"Only in the last 15 years have we come to understand that psoriasis is an autoimmune disease," Gelfand says. "Only in the past 10 years have we learned that psoriasis is promoted by the same immune pathways that are active in atherosclerosis." Atherosclerosis is hardening of the arteries, which contributes to coronary artery disease and heart attack risk.
More Study Needed
"We're learning so much about psoriasis and heart disease," Horn says. "But I don't think we understand enough about the risk to know how to modify it. For now, the best advice we can give patients is to work with their doctors to address the lifestyle and other risks that can be modified."
It's still unknown if psoriasis treatment -- which ranges from topically applied steroids to potent oral medications such as methotrexate -- has any effect on heart attack risk. "Patients should understand that," Gelfand says.
"It's also not clear how much skin disease you need to have before the risk increases," Gelfand says. Because the study defined severe psoriasis as "disease under treatment with oral medications" and mild psoriasis as "disease receiving milder or no treatment," it could not address that issue.
Further research is needed to confirm the new study's findings, focus on inflammatory markers common to psoriasis and atherosclerosis, explore whether or not some psoriasis treatments can reduce the risk of heart attack, and quantify the risk of heart attack by disease severity, Gelfand says.
"We're hoping to do that," Gelfand says. "Unfortunately, such studies are expensive to do."