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-alpha blockade yield a rapid improvement of endothelial function, we have sought to assess whether TNF-alpha 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-alpha 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.
Conclusion: 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 long-term use of drugs that act blocking TNF-alpha function to reduce the mechanisms implicated in the development of atherosclerosis in patients with RA.