People with rheumatoid arthritis can have clogged arteries withouthaving traditional cardiovascular risk factors. The likely culprit is chronic inflammation.

People with rheumatoid arthritis (RA) have a higher-than-average risk of suffering a heart attack or stroke. As a result, they’re advised to take steps to control any of the well-known heart disease risks, such as high blood pressure, elevated cholesterol, diabetes, and smoking. But, research has shown that the cardiovascular danger posed by RA goes beyond these traditional risk factors. (Cardiovascular refers to the heart and blood vessels.)

Now a new study has documented the buildup of plaque in the artery walls of many people with RA. Even when their other cardiovascular risk factors generally appear normal, plaque is present, clogging blood vessels. Plaque consists of hardened deposits of cholesterol, calcium, and other substances. Atherosclerosis is the accumulation of this plaque along artery walls.

People with RA tend to die earlier than those without the disease, usually from a heart attack or stroke. Normal findings on tests for traditional cardiovascular risk factors may be giving some people with RA a false sense of security, leading them to overlook atherosclerosis.
Assessing risk factors

The recent study was designed to detect signs of cardiovascular disease in people with RA. The study group consisted of 98 people with RA and 98 people of similar age and background without the disease (the control group). Cardiovascular risk factors were assessed in all participants. They included

• a family history of heart attack (in a father, brother, or son younger than age 55 or a mother, sister, or daughter before age 65)
• a smoking habit
• high blood pressure
• diabetes
• a high blood cholesterol level.

Other laboratory tests included blood work to measure rheumatoid factor (a marker of RA) and to detect signs of inflammation.

Among those with RA, the investigators also assessed the severity of their arthritis. They recorded the number of actively involved joints, evidence of disease beyond the joints (such as leg ulcers or the dry eyes and mouth associated with Sjögren’s syndrome), the number of severely damaged or replaced joints, and scores on a test of overall health. Information about participants’ medication use was obtained through interviews and a review of medical records.

Unrecognized danger

To look for evidence of undiagnosed cardiovascular disease, researchers focused on plaque in the carotid arteries, the 2 vessels in the neck that supply blood to the brain. They used ultrasound imaging to identify and measure plaque deposits that protruded from the artery lining into the hollow of the vessel through which blood flows. The condition of the carotid arteries usually predicts that of heart arteries.

Results of the ultrasound exams showed that people with RA were 3 times more likely (44% versus 15%) to have carotid atherosclerosis than those in the control group—despite having fewer other cardiovascular risk factors. The higher prevalence of atherosclerosis in people with RA was especially noticeable in younger participants. This points to RA as an independent risk factor for atherosclerosis.

Among people in the RA group, those who had carotid atherosclerosis were older, had suffered their arthritic disease longer, or had high blood pressure. (They were also more likely to have used a biologic drug called a tumor necrosis factor inhibitor to treat their RA. The researchers pointed out that this fact may simply indicate that their disease was more severe, not that the drug was a factor.) Blood levels of inflammatory substances were similar and higher than normal among all those with RA.

Chronic inflammation is the key

The researchers noted that the increased risk of carotid atherosclerosis in RA is similar to that found in people with systemic lupus erythematosus, another autoimmune disease (a condition in which the immune system turns on the body’s own tissues). This suggests that early onset of atherosclerosis may be common to chronic inflammatory diseases such as RA and lupus.

The researchers concluded that carotid ultrasound imaging is a simple way to identify atherosclerosis in people with RA before they develop symptoms of heart disease. It is important, they note, to treat RA aggressively in order to minimize inflammation.

From Annals of Internal Medicine