Feb. 4, 2005 ROCHESTER, MINN. -- Mayo Clinic researchers have found that rheumatoid arthritis patients have twice the risk of heart failure, or a weakening of the heart's ability to pump blood, as those without rheumatoid arthritis, according to a new study to be published in the February edition of the journal Arthritis & Rheumatism, http://www.rheumatology.org. About one-third of the rheumatoid arthritis patients studied developed heart failure over 30 years of the disease.
"We decided to undertake this study because we knew that patients with rheumatoid arthritis die earlier than the general population, and mostly from heart disease," says Paulo Nicola, M.D., Mayo Clinic research fellow in the Department of Health Sciences Research and study author. "We thought heart failure could be a reason for early mortality in these patients. However, we were not expecting that the incidence of heart failure would be so high."
The study found that patients with rheumatoid arthritis are at an increased risk for heart failure soon after the onset of arthritis and that this elevated risk follows them throughout the course of the arthritis, a chronic disease. The researchers also found that the factors putting them at this increased risk for heart failure seem to be unrelated to heart attacks and to the traditional cardiovascular risk factors: diabetes; alcohol abuse; and elevated cholesterol, blood pressure and body mass index. The source of the increased risk remains a mystery, however.
"We expected heart attacks and traditional cardiac risk factors to contribute to the increased risk of heart failure in rheumatoid arthritis patients, but they did not," says Dr. Nicola. "This suggests another mechanism is at work. We suspect that it has something to do with the underlying inflammation that occurs in people with rheumatoid arthritis. Another possibility is that patients with rheumatoid arthritis are particularly vulnerable to develop heart disease through a mechanism that we don't yet understand. These observations may also suggest the potential presence of a common susceptibility for developing rheumatoid arthritis or cardiac heart failure, or a shared origination of these diseases."
The study's researchers also noted little difference between rates of heart failure in men and women with rheumatoid arthritis.
"This is quite different from what you'd find in the general population, where rates of heart failure are significantly higher among men than in women," says Dr. Nicola. "This suggests that whatever protects women from heart failure compared with men in the general population is not the same in patients with rheumatoid arthritis."
Heart failure is a serious disease, according to Dr. Nicola, causing a survival as short as most cancers. He indicates that in the general population, about one-half of heart failure patients die within three to five years.
At present, the study investigators cannot prescribe preventive measures for rheumatoid arthritis patients to take in order to avoid heart failure; they suggest that this is a subject for further study. The Mayo researchers also are conducting studies to find out which rheumatoid arthritis patients are at highest risk for heart failure and to identify whether arthritis medications are protective or contributors to heart failure.
In the meantime, Dr. Nicola says, "Patients with rheumatoid arthritis should be vigilant regarding reducing their traditional cardiac risk factors. Their physicians should have a high degree of suspicion of heart failure -- for example, they should be suspicious when rheumatoid arthritis patients relate that they are more tired than normal."
The Mayo Clinic study utilized the resources of the Rochester Epidemiology Project, http://mayoresearch.mayo.edu/mayo/research/rep, which allowed the researchers to study a broad spectrum of individuals from the Rochester, Minn., area with all ranges of rheumatoid arthritis severity. The arthritis patients' experiences were measured against other study subjects who did not have rheumatoid arthritis but who matched the arthritis patients in age and gender. The arthritis patients were initially diagnosed between 1955 and 1995, and all individuals in the study were followed until death, heart failure, moving from Rochester, or Jan. 1, 2001. The researchers found that rheumatoid arthritis increased an individual's risk of heart failure 1.9 times the risk of those without the disease.
This study's senior investigator is Sherine Gabriel, M.D., Mayo Clinic rheumatologist, epidemiologist and chair of the Department of Health Sciences Research. Other Mayo Clinic study collaborators include: Hilal Maradit Kremers, M.D.; Veronique Roger, M.D., Steven Jacobsen, M.D., Ph.D.; Cynthia Crowson; and Karla Ballman, Ph.D.
The paper detailing these findings is entitled, "The Risk of Congestive Heart Failure in Rheumatoid Arthritis: A Population-Based Study Over 46 Years."
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