Three studies scheduled to be presented this week at the American College of Rheumatology's annual meeting in San Francisco (Oct. 24-29) found that rheumatoid arthritis nearly doubles the risk of having a heart attack. Moreover, people with rheumatoid arthritis who do suffer a heart attack are prone to have more heart-related complications compared with people without the condition.

Rheumatoid arthritis is an autoimmune disease caused by a malfunctioning immune system. How can you recognize arthritis? Well if you feel pain and stiffness in your body or have trouble moving around, you might have arthritis. Most kinds of arthritis cause pain and swelling in your joints. Over time, a swollen joint becomes severely damaged, but the negative impact on your body doesn’t end here, as some kinds of arthritis can also cause problems in your organs, such as your eyes or skin.

The disease is determined partly by genes and partly by factors such as smoking and drinking. Previous studies have shown that smoking increases the risk of the disease.

The Arthritis Foundation estimates that 1.3 million Americans suffer from rheumatoid arthritis.

The three studies were the work of Dr. Hilal Maradit Kremers, an epidemiologist at the Mayo Clinic in Rochester, Minn., Marie Gunnarsson, a doctoral student at the Institute of Environmental Medicine at the Karolinska Institute in Stockholm, Sweden and Dr. Kimberly Liang, an assistant professor at the University of Pittsburgh.

Dr. Kremers and colleagues tracked 38 patients with rheumatoid arthritis who had suffered a heart attack and compared them with patients without the condition who also had a heart attack.

The study showed that patients with rheumatoid arthritis had a 45 percent greater risk of developing heart failure after a heart attack compared with the general population, and a 75 percent greater risk of dying.

“Rheumatoid arthritis patients not only have more heart attacks and heart failures, but they also have worse prognosis once they have a cardiovascular event,” said Dr. Kremers.

In the second study, Gunnarsson and colleagues tracked data on 7,954 newly diagnosed rheumatoid arthritis patients and compared that information with 38,913 people from the general population in Sweden. The researchers found that rheumatoid arthritis had almost doubled the risk of a heart attack and dying from a heart attack over 10 years of follow-up.

The third study found that diastolic dysfunction occurred in 38.9 percent compared to 28.8 percent in the non-rheumatoid arthritis group. Diastolic dysfunction impairs the ability of the ventricles to fill with blood and can lead to heart failure.

“We also found that patients in the rheumatoid arthritis group had higher average pulmonary arterial pressure, which is high blood pressure in the lungs and the right side of the heart,” Dr. Liang said.

Given the findings, people diagnosed with rheumatoid arthritis should pay particular attention to cholesterol and blood pressure, known to increase heart attack risk, Dr. John Hardin, chief science officer at the Arthritis Foundation, said.