Novel cardiovascular risk factors and cardiac event predictors in female inactive systemic lupus erythematosus patients

Abstract

Systemic lupus erythematosus (SLE) is associated with severe and premature cardiovascular disease, which cannot be explained by traditional risk factors alone. This study aims to investigate novel cardiovascular risk factors and cardiac event predictors in inactive SLE female patients who do not have any major cardiovascular risk factors. Twenty-five inactive (SLE disease activity index score <4) SLE female patients and 22 healthy control women were studied. SLE patients with a history of diabetes mellitus, hypertension, hyperlipidemia, smoking, or coronary artery disease (CAD) were excluded. Venous blood samples were analyzed for lipid subfractions and novel cardiovascular risk factors such as lipoprotein (a), homocysteine, fibrinogen, high-sensitivity C-reactive protein (hs-CRP), and serum amyloid A (SAA) levels. Endothelial dysfunction was assessed by flow-mediated dilatation (FMD) from the brachial artery at baseline and during reactive hyperemia. SLE patients and controls were similar in terms of age (40+/-10 years vs 38+/-10 years, p = NS). No significant difference was found between the groups regarding family history of premature CAD, blood pressure, body mass index, lipoprotein (a), homocysteine, fibrinogen, SAA, apoprotein A-1 and B levels. Compared with the controls, SLE patients had higher levels of hs-CRP [median (range): 1.82 (0.02-0.98) vs 0.68 (0.02-0.35), p=0.04]. FMD was lower in SLE patients than controls (7.1+/-2.1 vs 11.4+/-1.2%, p<0.001). Increased levels of hs-CRP and decreased FMD were found in inactive SLE patients. Increased hs-CRP levels may reflect ongoing low-grade inflammation that could be a cause of impaired FMD in SLE patients. These findings suggest that SLE patients without traditional major cardiovascular risk factors may have increased risk of cardiovascular disease and future cardiac events.