Objective. Systemic inflammation, insulin resistance, and endothelial dysfunction have been implicated in the development of cardiovascular disease in rheumatoid arthritis (RA). Since insulin resistance can promote endothelial dysfunction and anti-TNF-α blockade yield a rapid improvement of endothelial function, we have sought to assess whether TNF-α blockade may also result in a reduction of insulin serum levels and improvement of insulin resistance in RA patients who require this therapy because of severe and refractory disease.

Methods. We recruited patients with RA seen over a period of 1 month at Hospital Xeral-Calde, Lugo, Spain, that were on treatment with anti-TNF-α monoclonal antibody-infliximab. Patients with diabetes mellitus or plasma glucose> 110 mg/dl were excluded. Fasting blood samples were taken for determination of plasma glucose and serum insulin levels immediately prior to and after infliximab infusion. Results. Twenty-seven RA patients (21 women; mean age: 57.1 years; mean DAS28: 4.43) fulfilled the inclusion criteria. Dramatic reduction in the serum insulin levels and insulin/glucose index was observed following infliximab infusion. Also, a significant improvement of insulin resistance and insulin sensitivity was found. Conclusions. Our study confirms a rapid beneficial effect of infliximab on insulin resistance and insulin sensitivity in RA patients treated periodically with this drug. It may support the longterm use of drugs that act blocking TNF-α function to reduce the mechanisms implicated in the development of atherosclerosis in patients with RA.