Circulating interleukin-6 and cardiovascular disease risk in patients with rheumatoid arthritis with low disease activity due to active therapy.

Objectives: Interleukin-6 (IL-6) has been implicated in the pathophysiology of rheumatoid arthritis (RA) and in the development of atherosclerosis in the general population. In the present work we aimed to study if IL-6 serum levels have an influence on factors associated with cardiovascular (CV) disease in a cohort of Spanish patients with RA.
Methods: Cross-sectional study that encompassed 407 patients with RA. Serum IL-6 levels were assessed. Multivariable analysis was performed to examine the relationship of IL-6 to subclinical carotid atherosclerosis and classic CV risk factors, including a comprehensive lipid molecule profile and indices of insulin resistance and beta-cell function.
Results: Circulating levels of IL-6 showed a correlation with acute phase reactants, disease activity, and other features of RA. However, classic CV risk factors, lipid profile and indices of insulin resistance, as well as subclinical carotid atherosclerosis, were not associated with serum IL-6 levels.
Conclusions: Although a direct association between IL-6 levels and traditional CV risk factors and subclinical carotid atherosclerosis was not observed, circulating IL-6 was associated with disease activity and acute-phase reactants, which have been associated with an increased risk of CV in these patients.