NEW ORLEANS – Patients with severe psoriasis face a 6% higher 10-year risk for a cardiovascular event than do comparable people without psoriasis, according to the findings of a prospective cohort study of nearly 18,000 people.
This added cardiovascular risk can have substantial implications, as it can move psoriasis patients into a higher Framingham Risk Score category and shift the way physicians need to think about cardiovascular risk management of these patients, Dr. Nehal N. Mehta said at the annual meeting of the American College of Cardiology.
In his practice that focuses on adults with psoriasis, the average background Framingham Risk Score based on low density lipoprotein cholesterol is a 7% 10-year risk for having a cardiovascular event, a level defined as low risk. However, adding the 6% additional risk linked with their psoriasis results in many patients having a 10-year risk of 13% or higher, placing them in the intermediate risk category (generally defined as a 10%-20% risk of having a cardiovascular event).
Patients at that intermediate risk category usually have more stringent targets for lipid levels, blood pressure, and weight although, in this context, it's unclear whether patients who leap into a higher cardiovascular risk level because of their psoriasis require more aggressive medical management; cardiovascular risk management guidelines have yet to elucidate optimal management for this patient subgroup.
Dr. Mehta deals with this dilemma by implementing aggressive lifestyle interventions for these patients, and also by suggesting naturally occurring risk-reduction interventions, such as the consumption of fiber, red yeast rice, soy, phytoestrogens, fish oil, and niacin. If, after all these interventions, a patient's low density lipoprotein cholesterol or blood pressure remains at a questionably high level, he discusses the option of starting treatment with a statin or an antihypertensive medication, making clear that these steps have not yet been endorsed by most society management guidelines.
"Ultimately, about 5% of my psoriasis patients end up on a statin," said Dr. Mehta, a cardiologist and director of the inflammatory risk clinic in preventive cardiology at the University of Pennsylvania, Philadelphia.
Dr. Mehta and his associates derived an estimate of cardiovascular disease risk attributable to psoriasis by reviewing follow-up data maintained on 3,603 patients with severe psoriasis and 14,330 control participants without psoriasis enrolled in the General Practice Research Database, a collection of records from more than 5 million people seen by U.K. general practice physicians. The researchers identified cases of severe psoriasis based on their receiving systemic therapy or phototherapy and excluded people with a prior history of cardiovascular events. The average age of all the people in the analysis was about 50 years and, on average, people were followed for about 3 years.
In a multivariable analysis that controlled for diabetes, hypertension, hyperlipidemia, age, gender, body mass index, and smoking status, the risk for a myocardial infarction, stroke, or death from a cardiovascular cause was 53% higher among the psoriasis patients, compared with the controls, a statistically significant difference. This higher cardiovascular risk among patients with psoriasis matched the 50% increased risk proposed last year for patients with rheumatoid arthritis and other forms of inflammatory arthritis including psoriatic arthritis, according to a panel convened by the European League Against Rheumatism (Ann. Rheum. Dis. 2010;69:325-31).
To translate the 1.53 relative risk into an attributable risk, Dr. Mehta and his associates multiplied that factor against the background cardiovascular risk for someone in the general population of the study to derive an adjusted risk. They then subtracted the background risk from the adjusted risk. Over a 10-year period, this translated into an excess risk for a cardiovascular event of 6.2%.
To illustrate the potential impact of this estimate, the researchers then applied this to a consecutive sample of 103 psoriasis patients seen in Dr. Mehta's psoriasis clinic at the Penn Heart and Vascular Center, including nine patients with psoriatic arthritis. The baseline risk for these men and women averaged 7.3%, a low-risk level, but with the additional 6.2% risk added their functional risk jumped to an average of 13.5%, or to the intermediate-risk level. For individual patients, this signaled a substantial shift in their Framingham Risk Score risk level. Dr. Mehta conceded that the risk adjustment he applied derived from patients with severe psoriasis, while only 10% of patients in his practice have severe disease. About 60% have mild psoriasis, and about 30% have moderately severe disease, he said.
"This is the best we can do" for the time being, he said. "We applied the severe psoriasis metric to everyone to get a hazard estimate. We believe this is better than just multiplying" to recalculate a person's risk, the approach suggested by the EULAR committee. He hopes that a larger, prospective study he has begun in collaboration with Dr. Joel M. Gelfand, a dermatologist at the University of Pennsylvania and the senior investigator for this work, will eventually provide a more nuanced risk adjustment for all levels of psoriasis severity. But he said that the current estimate of the increased risk will help persuade psoriasis patients to adopt healthier lifestyles. Patients with psoriasis, at all severity levels, tend to have relatively high rates of obesity, smoking, diabetes, hypertension, and inactivity.