Objective: Several factors have been implicated in the high prevalence of premature coronary artery disease (CAD) in patients with systemic lupus erythematosus (SLE). We hypothesize that variables independent of traditional risk factors contribute significantly to the development of CAD in SLE. We investigated the relative contribution of traditional risk factors in SLE patients with CAD compared to non-SLE patients with premature CAD.
Methods: An age matched retrospective cohort analysis. The prevalence of traditional cardiovascular risk factors (hypertension, hypercholesterolemia, diabetes, smoking, family history) in patients with SLE who developed CAD during the course of their illness was compared to a group of age matched non-SLE subjects with premature CAD. Sexes were analyzed separately using Fisher's exact test and unpaired t tests.
Results: Thirty-five patients with SLE (27 women, 8 men) with definite ischemic heart disease were identified along with 397 non-SLE subjects (83 women, 314 men). In women with SLE the mean number of CAD risk factors per cardiac event was 2.0 +/- 0.77 versus 2.90 +/- 1.19 for the comparison group (p = 0.0008). In men with SLE the mean number of CAD risk factors was 1.87 +/- 0.83 versus 2.73 +/- 0.99 in the comparison group (p = 0.016).
Conclusion: SLE patients with a cardiac event have fewer traditional risk factors than non-SLE patients with premature CAD. Thus premature CAD in SLE cannot be attributed solely to an excess of traditional risk factors.