Risk of Heart Attack Nearly Doubles within First 10 Years of RA Diagnosis

Released: 22-Oct-2008 1:00 PM EDT
Embargo expired: 25-Oct-2008 8:00 PM EDT
Source Newsroom: American College of Rheumatology (ACR)
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Newswise — A person's risk of heart attack nearly doubles within the first ten years after being diagnosed with rheumatoid arthritis, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Francisco, Calif.

Rheumatoid arthritis is a chronic disease that causes pain, stiffness, swelling, and limitation in the motion and function of multiple joints. Though joints are the principal body parts affected by RA, inflammation can develop in other organs as well. An estimated 1.3 million Americans have RA, and the disease typically affects women twice as often as men.

Using the Swedish RA Register, researchers identified 7,954 patients who were newly diagnosed with RA, and—for comparison—matched them with 38,913 individuals from the general population. Patients in the RA group were, on average, 57 years old and 69 percent female. The two groups were followed for over 10 years, and researchers collected information from both groups on heart attacks and deaths from heart attacks, as well as death from other causes.

After adjusting for high blood pressure and diabetes, researchers assessed the average rate at which participants experienced a heart attack, died from a heart attack, and died from all other causes compared with people without RA. Their investigation showed that before diagnosis, those who were eventually diagnosed with RA were not more likely to have had heart attacks. However, once diagnosed with RA, these numbers changed dramatically. The relative risk for heart attack in the RA group increased continuously after diagnosis, and death from a heart attack increased over time (beginning five or more years after diagnosis). During their first decade with the disease, these patients had nearly double the number of heart attacks and deaths due to heart attacks.

"This study shows that having rheumatoid arthritis confers an increased risk of having a myocardial infarction, and that this risk increase is manifest already early in RA disease progress, explains Marie Gunnarsson, PhD student; Institute of Environmental Medicine, department of cardiovascular epidemiology; Karolinska Institutet, Stockholm, Sweden. "The fact that there is no increased risk prior to RA diagnosis suggests that there is something in the RA disease itself, such as inflammatory processes that lead to this increased risk. Measures to bring down inflammation in RA might, thus, be beneficial also from a cardiovascular prevention point of view in this population."

Editor's Notes: Dr. Gunnarsson will present this research during the ACR Annual Scientific Meeting at the Moscone Center from 9:00 " 11:00 AM on Monday, October 27, in Hall A.


Presentation Number: L5

From No Increase to Doubled Risk After Ten Years: Morbidity and Mortality from Myocardial Infarction in Newly Diagnosed Rheumatoid Arthritis

Marie Gunnarsson1, Lars Alfredsson1, Lennart Jacobsson2, Lars Klareskog3, Solbritt Rantapää Dahlqvist4, Johan Askling3. 1Karolinska Institute, Institute of Environmental Medicine, Stockholm, Sweden; 2Rheumatology Unit, Department of Medicine, Malmö University Hospital, Malmö, Sweden; 3Rheumatology Unit, Department of Medicine, Karolinska University Hospital, Stockholm, Sweden; 4Department of Rheumatology, Umeå University Hospital, Umeå, Sweden

Background: While cardiovascular disease (CVD) morbidity and mortality are known to be increased in patients with rheumatoid arthritis (RA), less is known about how these risks evolve from RA onset and onwards.

Objectives: To assess the relative risk of incident myocardial infarction (MI), death from MI, and all cause mortality at RA onset by time since RA diagnosis.

Methods: From the Swedish RA registry, ongoing since 1995, we identified 7,954 patients with newly diagnosed RA (<18 months of symptoms at inclusion). As a comparator cohort, 5 individuals from the general population were selected for each RA patient, matched for age, sex, calendar year, residential area and marital status (n=38, 913). Information on incident MI was retrieved from the nationwide Swedish Hospital Discharge Register (through 2006). Information on death from MI was retrieved from the Cause of Death Registry (through 2005), and on all-cause deaths from the Population Registry (through January 2008). To assess the risk of a history of MI up until RA-diagnosis, we used conditional regression models taking the matching variables into account, and with adjustments for diabetes and hypertension. To assess relative risks of MI morbidity and mortality following RA-diagnosis we used Cox' proportional hazard regression models, adjusting for diabetes and hypertension regarding MI morbidity.

Results: Mean age at start of follow-up was 57 years. 69% were women. Follow-up amounted to 32247 person-years in the RA cohort and 198877 person-years in the general population cohort. Mean time of follow-up for MI was 5.0 years, death from MI 4.7, and all-cause death 5.8 in both cohorts. By the time of RA-diagnosis, patients were not more likely to have a history of MI than their controls (OR 1.0, 95% CI 0.9-1.2). By contrast, from RA-diagnosis and onwards the relative risk of incident MI increased continuously. Mortality from MI, also increased over time of follow-up, beginning 5 or more years after RA diagnosis.

Conclusion: By the time of diagnosis of RA, patients do not have an increased morbidity from MI, which also, based on other materials, has been reported elsewhere1. During their first decade with disease, the risks of incident MI and death from MI increase to an almost doubling of the background risk.
Footnotes
1 ACR 2008, Presentation no 690

[Table included with press release and full abstract at www.rheumatology.org.]

Disclosure Block: M. Gunnarsson, None; L. Alfredsson, None; L. Jacobsson, None; L. Klareskog, None; S. Rantapää Dahlqvist, None; J. Askling, None.


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