To determine the risk of myocardial infarction (MI) in patients with rheumatoid arthritis (RA) compared with that in patients with noninflammatory rheumatic disorders and to determine risk factors for MI in RA, the relationship between cardiovascular risk factors and corticosteroid use, and the relationship between RA treatment and MI.
We conducted a cohort study of MI in 17,738 patients with RA and 3,001 patients with noninflammatory rheumatic disorders who were assessed at 6-month intervals between 1999 and July 2006. We evaluated treatment effect in a nested case-control study of RA participants who were matched by age, sex, study duration, and date of study entry.
The covariate-adjusted risk of first MI in RA versus that in noninflammatory rheumatic disorders was 1.9 (95% confidence interval 1.2-2.9) (P = 0.005). In RA, MI was predicted by age, sex, education level, hypertension, smoking, exercise, prior MI, diabetes, a comorbidity index, use of low-dose aspirin and antilipemic agents, RA severity and treatment variables, and corticosteroid use. Except for obesity, predictors were of equal strength in RA and noninflammatory rheumatic disorders. The increased risk for MI in RA compared with that in noninflammatory rheumatic disorders lessened when corticosteroid users were excluded. Use of corticosteroids was associated with future development of diabetes and hypertension.
MI in RA is associated with demographic and cardiovascular risk factors and corticosteroid use. Study data support the hypothesis that RA activity causes MI and that corticosteroids are primarily a marker of RA activity. However, corticosteroids increase the risk of diabetes and hypertension and contribute to the overall risk of MI.