Insulin-like growth factor I: a predictor of long-term glucose abnormalities in patients with acute myocardial infarction.

Low levels of IGF-I are associated with increased risk of cardiovascular disease and type 2 diabetes. The aim of this study was to investigate the IGF-I system in patients with acute myocardial infarction (AMI) without previously known diabetes. One hundred and sixty-eight AMI patients were classified before hospital discharge by means of an OGTT as having NGT, IGT or newly detected type 2 diabetes. Age- and sex-matched subjects from the background population (n=185) served as the control group. The associations between fasting levels of IGF-I and IGF binding proteins 1 and 3 (IGFBP-1, IGFBP-3) and glucose metabolism during a follow-up period of 12 months were studied. At hospital discharge, age-adjusted IGF-I (IGF-I SD) was significantly lower in patients with abnormal glucose tolerance (AGT=IGT or type 2 diabetes) compared with patients with NGT (p=0.014) and control subjects (p<0.001). IGF-I was strongly correlated with IGFBP-3 (r=0.730, p<0.001), which was significantly lower in patients with AGT compared with patients with NGT (p=0.009) and control subjects (p<0.001). Fasting levels of IGFBP-1 did not differ significantly between patients with NGT and AGT or between patients and control subjects. In a multiple logistic regression analysis in patients, IGF-I at hospital discharge was a significant predictor of AGT at discharge and after 12 months (adjusted odds ratio 0.29, p=0.022, and adjusted odds ratio 0.29, p=0.034, respectively). Low levels of IGF-I may be a useful predictor of abnormal glucose metabolism in patients with AMI.