Objective: To assess whether obesity and systemic inflammation are potential determinants of circulating adiponectin concentrations and whether low adiponectin levels cluster with metabolic syndrome features that are previously documented cardiovascular risk factors in rheumatoid arthritis (RA).
Methods: We investigated 33 RA patients who were treated with the TNF-alpha antagonist infliximab, immediately prior to an infliximab infusion. Adiponectin levels were also determined immediately after administration of an infliximab dose.
Results: Adiponectin concentrations correlated with age (R=0.465, p=0.008) and were higher in women (mean [95% confidence interval]=21,595 [15,366 to 30,349] ng/ml) than in men (9,310 [5,653 to 15,335] ng/ml)(p=0.008). C-reactive protein (CRP) levels correlated with circulating adiponectin concentrations (partial (p) R=-0.370, p=0.04), independent of age and gender. By contrast, the body mass index (BMI) did not correlate with adiponectin levels (pR=-0.039, p=0.8). Adiponectin concentrations correlated with triglycerides/HDL cholesterol ratios (pR=-0.396, p=0.03), total cholesterol/HDL cholesterol ratios (pR=-0.444, p=0.01) and high fasting plasma glucose levels (pR=-0.366, p=0.04), independent of CRP levels and the BMI. Adiponectin levels did not change (p=0.3) upon infliximab administration.
Conclusion: In this cohort, high-grade inflammation was independently and negatively correlated with circulating adiponectin concentrations whereas low adiponectin levels clustered with metabolic syndrome features that reportedly contribute to atherogenesis in RA. Circulating adiponectin may be involved in cardiovascular disease in RA. The impact of inflammation on circulating adiponectin concentrations is not likely to be TNF-alpha mediated in RA.