Rheumatoid arthritis patients had significantly higher long-term mortality after myocardial infarction than did matched MI patients without RA in a review of a population-based cohort of patients.
RA patients also exhibited an increased risk of recurrent ischemia, compared with patients who did not have RA, reported Dr. Sara S. McCoy of the Mayo Clinic, Rochester, Minn., and her colleagues (J. Rheumatol. 2013 Feb. 15 [doi:10.3899/jrheum.120941]).
Dr. McCoy and her coinvestigators analyzed data from the Rochester Epidemiology Project, which includes records from all health care providers for the population of Olmsted County, Minn. They targeted 77 RA patients and 154 age- and sex-matched patients without RA who had an MI between Jan. 1, 1979, and Jan. 1, 2010.
Overall, 55% of patients in both cohorts were female; the mean age at MI was 72.4 years. There were no significant differences between cohorts regarding MI risk factors such as hypertension, dyslipidemia, diabetes, smoking status, and obesity. MI characteristics, severity, and electrocardiogram findings were also similar between groups.
Additionally, RA patients and their unaffected counterparts had no differences in treatment during and after MI and in-hospital mortality (5% of RA patients vs. 8% of controls, P = .37). Mortality at 30 days post MI and at 1 year post MI was also similar.
The similarities ended for long-term mortality. Dr. McCoy and her associates found that during a median follow-up of 2.6 years among the RA cohort, 55 patients died, compared with 85 patients over a median 2.7 years in the control cohort, for a hazard ratio of mortality among RA patients of 1.47, compared with their counterparts (95% confidence interval, 1.04-2.08).
The finding held when extended out to 5 years, with the mortality rate among RA patients at 57%, compared with 36% among controls (log rank P = .036).
"Cardiovascular causes [of death] were found in 28 deaths among patients with RA and in 40 deaths among patients without RA," added the authors, although "there was no apparent difference between groups in the proportion of deaths due to CV causes."
Recurrent ischemia also was more pronounced among the RA patients. At 5 years, 80% of RA patients and 50% of controls had experienced ischemia (log rank P = .043).
The conclusions that can be drawn from the study are limited by its retrospective design, as well as the fact that very few data were collected on RA disease activity at the time of MI.
"Erythrocyte sedimentation rate was documented in less than half the cohort in the months prior to MI, and no other measure of disease activity was consistently used or documented over the study time period," the investigators wrote.
The study also was underpowered to assess any associations between mortality and RA characteristics.
"If RA disease characteristics do indeed play a role in determining long-term survival after MI in persons with RA, this would argue for a more personalized, disease-specific approach to post-MI management for patients with RA, similar to post-MI management in patients with diabetes mellitus," they wrote.
"More research is needed to understand the determinants of long-term outcomes after MI in patients with RA, in particular, the role of RA disease characteristics."
Dr. McCoy and her colleagues disclosed no relevant conflicts of interest. They disclosed funding from the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Heart, Lung, and Blood Institute. The Rochester Epidemiology Project is funded by the National Institute on Aging.