C-reactive protein levels following acute myocardial infarction: effect of insulin infusion and tight glycemic control.

A cute myocardial infarction (AMI) triggers an inflammatory reaction, which plays an important role in myocardial injury (1). Inflammatory markers such as C-reactive protein (CRP) reflect the extent of myocardial necrosis and correlate with cardiac outcomes following AMI (2–4). Hyperglycemia has proinflammatory effects, inducing the release of inflammatory cytokines (5) and is associated with increased mortality from AMI (6,7). Conversely, insulin-based therapy in patients following AMI may confer survival benefits, but the mechanism is unclear (8–11). Insulin suppresses the inflammatory response (12), but it is uncertain if the antiinflammatory effect of insulin therapy depends on glycemic status. The Hyperglycemia: Intensive Insulin Infusion In Infarction (HI-5) study is a multicentered randomized trial of insulin infusion for hyperglycemic patients with AMI. In this substudy, we examined the relationship between blood glucose levels (BGLs) and the inflammatory response (CRP levels) following AMI and evaluated the effect of insulin-based infusion therapy.