Metabolic syndrome in rheumatic diseases: epidemiology, pathophysiology, and clinical implications

Abstract

Subjects with metabolic syndrome--a constellation of cardiovascular risk factors of which central obesity and insulin resistance are the most characteristic--are at increased risk for developing diabetes mellitus and cardiovascular disease. In these subjects, abdominal adipose tissue is a source of inflammatory cytokines such as tumor necrosis factor-alpha, known to promote insulin resistance. The presence of inflammatory cytokines together with the well-documented increased risk for cardiovascular diseases in patients with inflammatory arthritides and systemic lupus erythematosus has prompted studies to examine the prevalence of the metabolic syndrome in an effort to identify subjects at risk in addition to that conferred by traditional cardiovascular risk factors. These studies have documented a high prevalence of metabolic syndrome which correlates with disease activity and markers of atherosclerosis. The correlation of inflammatory disease activity with metabolic syndrome provides additional evidence for a link between inflammation and metabolic disturbances/vascular morbidity.

Figure 1

Pathophysiology of the metabolic syndrome: both insulin resistance and lipid overflow contribute to MetS evolution. IL-6, interleukin-6; MAP, mitogen-activated protein; TNF-α, tumor necrosis factor-alpha.