Insulin resistance is closely associated with an increased risk of subclinical atherosclerosis in patients with rheumatoid arthritis (RA). Anti-TNF therapy reduces insulin resistance and improves insulin sensitivity in patients with severe RA. New findings have shown, however, that the efficacy of these agents in this regard is impaired by obesity. Gonzalez-Gay, M. A. & Gonzalez-Juanatey, C. Nat. Rev. Rheumatol. 8, 641-642 (2012); published online 25 September 2012; doi:10.1038/nrrheum.2012.158