Rheumatoid arthritis (RA) is associated with an unexplained increased cardiovascular risk. Autoantibodies recognizing oxidized low-density lipoprotein (oxLDL-ab) are associated with atherosclerosis in the general population and have been reported in several autoimmune diseases. We investigated relations between oxLDL-ab, inflammation, subclinical atherosclerosis, and cardiovascular disease (CVD) in patients with RA.
In a nested case-control study, serum concentrations of oxLDL-ab were measured in 140 RA patients. Ultrasound examination of the carotid artery [i.e., carotid intima-media thickness (CIMT)] was performed in a third of these patients. Correlations were calculated for oxLDL-ab, C-reactive protein (CRP), and high-density lipoprotein (HDL) cholesterol. Regression analyses were used to examine associations between oxLDL-ab and prevalent CVD, and oxLDL-ab and CIMT.
OxLDL-ab were positively correlated with CRP (r = 0.33, p < 0.001) and negatively correlated with HDL cholesterol (r = -0.28, p = 0.001). An indication for interaction was found (p = 0.09), suggesting that inflammation modifies the relation between HDL cholesterol and oxLDL-ab. OxLDL-ab were independently associated with intimal thickening, but not associated with prevalent CVD.
OxLDL-ab were strongly related with the degree of inflammation and may predispose to a higher risk for CVD, as they were independently associated with subclinical atherosclerosis in patients with RA.