The connection between psoriasis and heart disease has been in the news lately, and is naturally of great concern to psoriasis patients. We try to make sense of it in this article.
The Journal of the American Medical Association (JAMA) reported in October 2006 that psoriasis increases a person’s chances of having a heart attack.1 People whose psoriasis was severe enough to require treatment with a whole body medication such as methotrexate were at the greatest risk, although even those with milder disease were detectably affected. Psoriasis appeared to play a bigger role in heart disease in young people—a 30-year old with severe psoriasis was approximately three times (300%) more likely to suffer a heart attack than a 30-year old from the general population, but a 60-year old with severe psoriasis had only a 36% higher risk than his same-aged peers. Importantly, in this study heart attacks were, as always, rare among young people, so despite the 300% increased risk, the number of heart attacks that occurred in young psoriasis patients was extremely low. For those with mild psoriasis, the increased risk was 29% at age 30 and 8% at age 60.
The idea that psoriasis can contribute to heart disease is not new; there have been suggestions of a link in the medical literature since the 1970’s.2,3 However, the JAMA study, conducted by Joel M. Gelfand, MD, MSCE and colleagues at the University of Pennsylvania, is by far the largest and most comprehensive investigation of its kind. Using electronic medical records, they collected data on nearly all adult psoriasis patients who were seen by more than 1500 general practitioners in the United Kingdom between 1987 and 2002. All in all, they followed approximately one hundred thousand psoriasis patients and half a million patients without psoriasis who attended the same medical practices. They used those without psoriasis as “controls,” so they could compare people with psoriasis to similar people without the disease. In addition to tracking the severity of psoriasis and the occurrence of heart attacks, the researchers took note of other known heart disease risks, including high blood pressure, high cholesterol, and smoking and subtracted out the influence of these factors in their analysis.
Michael T. Nurmohamed, MD, PhD, a rheumatologist at VU University Medical Center and the Jan van Breemen Institute in Amsterdam, the Netherlands who has investigated heart disease in psoriatic arthritis patients4, praised the study for being “well designed.” “Although these kinds of studies have inherent methodological problems most … were adequately addressed,” he added.
Although the work clearly indicates a connection between psoriasis and heart attacks, it does not explain why the connection exists. One possibility is that the immune system dysfunction associated with psoriasis may directly contribute to heart attacks. Most heart attacks are the result of atherosclerosis, the development of plaques, or thickenings, in the walls of the arteries within the heart.5 Plaques form at the sites of cholesterol deposits and can be stable and harmless for many years. However, if a plaque becomes inflamed it can rupture, blocking blood flow in the artery and triggering a heart attack. In psoriasis patients, immune cells congregate in the skin and, among other things, release inflammatory molecules into the bloodstream that could raise the risk of plaque rupture. “Nowadays, we know that atherosclerotic disease should be seen as an inflammatory disease,” said Nurmohamed. “Hence, it appears that inflammation [could be] the coupling between [psoriasis and heart disease].”
If inflammation is the key, said Nurmohamed, then patients with psoriatic arthritis, who have higher levels of inflammatory molecules than those with skin disease alone, might be expected to have the highest risk of heart attacks. Unfortunately, the JAMA study did not distinguish between patients with and without arthritis.
Another possible explanation for higher heart attack risk in psoriasis patients is medication usage. For example, patients with psoriatic arthritis may take large doses of non-steroidal anti-inflammatory drugs, which have been shown in some other studies to modestly increase heart attack risk.6
Nurmohamed also raised the possibility that early heart disease may be under-treated in psoriasis patients, leading to higher heart attack rates. Studies have shown that patients with chronic diseases (such as psoriasis) that demand considerable time and attention during doctor visits often receive less than optimal care for other medical conditions.7
Interestingly, the study by Gelfand et al. also indicated that patients with psoriasis are more likely than the general population to have diabetes, high cholesterol, and other “traditional” risk factors for heart disease.1,8 The presence of these other factors further increases heart attack risk over and above the risk due to psoriasis alone. The explanation could again be immunological. Patients suffering from the metabolic syndrome, a combination of disorders including obesity, high blood pressure, high cholesterol, and pre-diabetes, exhibit immune system abnormalities similar to those seen in psoriasis patients and also have a high rate of heart attack. However, the explanation could also be behavioral. The psychological stress of living with psoriasis could contribute to poor diet choices and to an increased tendency to smoke, and both psychological and physical effects of psoriasis could impair exercise habits.
“Obviously, confirmatory research is needed. Another aspect which needs to be addressed is whether the cardiovascular risk decreases with tight [psoriasis] disease control,” said Nurmohamed. Some experts theorize that aggressive treatment of psoriasis could minimize the increased heart disease risk. In the meantime, both the study’s authors and Nurmohamed recommend that psoriasis patients should do what they can to control other heart disease risk factors. Therefore, just like everyone else, they should try to maintain a healthy weight, avoid smoking, and should seek treatment for conditions such as high blood pressure and high cholesterol.
1. Gelfand et al. “Risk of Myocardial Infarction in Patients with Psoriasis.” JAMA. 2006 Oct 11;296(14):1735-41. [return to article text]
2. McDonald and Calabresi. “Complication of Psoriasis.” JAMA. 1973 Apr 30;224(5):629. [return to article text]
3. McDonald and Calabresi. “Occlusive Vascular Disease in Psoriatic Patients.” N Engl J Med. 1973 Apr 26;288(17):912. [return to article text]
4. Peters et al. “Cardiovascular Risk Profile of Patients with Spondylarthropathies, Particularly Ankylosing Spondylitis and Psoriatic Arthritis.” Semin Arthritis Rheum. 2004 Dec;34(3):585-92. [return to article text]
5. Hansson. “Inflammation, Atherosclerosis, and Coronary Artery Disease.” N Engl J Med. 2005 Apr 21;352(16):1685-95. [return to article text]
6. Cheng. “Use of Non-aspirin Nonsteroidal Antiinflammatory Drugs and the Risk of Cardiovascular Events.” Ann Pharmacother. 2006 Oct;40(10):1785-96. [return to article text]
7. Redelmeier et al. “The Treatment of Unrelated Disorders in Patients with Chronic Medical Diseases.” N Engl J Med. 1998 May 21;338(21):1516-20. [return to article text]
8. Neimann et al. “Prevalence of Cardiovascular Risk Factors in Patients with Psoriasis.” J Am Acad Dermatol. 2006 Nov;55(5):829-35. [return to article text]