Well before rheumatoid arthritis patients receive their diagnosis, they are three to six times more likely than are those without the disease to suffer acute myocardial infarction, results from a large retrospective study have shown.
The results support the idea that the heart disease associated with rheumatoid arthritis (RA) is not an issue for the back burner.
Physicians and their patients need to recognize that heart disease may not only be present, but well underway and quite serious at the time of RA diagnosis, the study's lead author, Hilal Maradit-Kremers, M.D., said in an interview.
Furthermore, the findings “certainly fit with the sense that a period of systemic inflammation antedates the clinical diagnosis of RA, and this systemic inflammatory burden increases cardiovascular risk,” said Mary Chester Wasko, M.D., of the division of rheumatology and clinical immunology at the University of Pittsburgh, who was not affiliated with the study.
Dr. Maradit-Kremers and her associates at the Mayo Clinic, Rochester, Minn., conducted the population-based cohort study, which involved 603 Rochester residents who fulfilled American College of Rheumatology (ACR) criteria for RA between January 1955 and January 1995, and 603 age- and gender-matched controls from the area (Arthritis Rheum. 2005;52:402-11).
They collected data on coronary heart disease (CHD) events and risk factors such as diabetes, hypertension, dyslipidemia, body mass index, and tobacco smoking.
CHD events included hospitalization for MI, unrecognized MI, coronary revascularization procedures, and sudden CHD deaths.
The investigators used conditional logistic regression and Cox regression to estimate the risk of CHD associated with RA before and after the RA diagnosis.
The mean age of study participants in both cohorts was 58 years, and nearly three-fourths (73%) were female.
The investigators observed that 2 years prior to being diagnosed with RA, patients with the disease were 3.17 times more likely than were their non-RA counterparts to have been hospitalized for acute MI and 5.86 times more likely to have experienced unrecognized MIs.
After receiving their diagnosis of rheumatoid arthritis, those patients were 1.09 times more likely than their non-RA counterparts to be hospitalized with MI, 2.13 times more likely to have unrecognized MI, and 1.94 times more likely to experience sudden cardiac death.
The risk estimates did not change significantly when the investigators adjusted for the CHD risk factors.
In an interview, Dr. Maradit-Kremers called the findings “another piece of evidence that inflammation is related to atherosclerosis and coronary heart disease.” The findings support the use of RA as a model to study the effects of chronic inflammation on the cardiovascular system.
“We haven't studied whether a more vigilant approach [to monitoring RA patients for heart disease] would be more beneficial, but our findings imply that it would be beneficial,” Dr. Maradit-Kremers added.
At baseline, 30% of the RA patients were current smokers and 26% were former smokers, compared with 24% and 20% of the non-RA patients, respectively. “When we think about interventions that a physician might implement to reduce cardiovascular risk, smoking is one that really stands out,” Dr. Wasko said. “Physicians need to be proactive about trying to minimize modifiable risk factors such as tobacco use.”
Limitations of the study, the investigators noted, include the fact that more than 95% of the study population was white and that only 57% of the RA patients received a disease-modifying antirheumatic drug.
Dr. Wasko pointed out that RA is more effectively controlled with disease modifying agents today than it was when the study ended in 1995. “One wonders if the study cohort were larger, or if the study were extended through the current era, perhaps the findings would be different,” Dr. Wasko said.
“Earlier diagnosis of RA and prompt initiation of effective disease-modifying agents such as methotrexate and anti-TNF [tumor necrosis factor] therapies may favorably impact CHD risk in patients with this disease,” Dr. Wasko said.
“This research is unique and is an interesting contribution to our understanding of both coronary heart disease and increased risk of CHD in RA,” she added.