Patients with rheumatoid arthritis have a significantly higher risk to develop heart attacks and other complications of their blood vessels. New therapies are needed to prevent this complication. The purpose of this study is to establish the role of the medication pioglitazone in improving the function of the blood vessels and heart and decreasing the risk of future atherosclerosis development in individuals with rheumatoid arthritis. As a secondary aim-point, we will evaluate the efficacy of pioglitazone in improving rheumatoid arthritis disease activity and markers of inflammation.