Aims: To study the impact of disturbances in glucose metabolism on total mortality in non-diabetic patients with acute myocardial infarction.
Methods and results: Four hundred and ninety four patients with a verified myocardial infarction and no history of diabetes were studied. The study population comprised a subgroup of patients screened for participation in the Trandolapril Cardiac Evaluation (TRACE) study. At baseline, fasting insulin, fasting glucose, glycosylated haemoglobin (HbA1c), and urinary albumin excretion were measured. Survival status was determined after 6-8 years. Patients with hyperinsulinaemia were more obese and more frequently suffered from hypertension, previous myocardial infarction and congestive heart failure. In a univariate regression analysis, values in the upper quartile of insulin, glucose, HbA1c, and urinary albumin were associated with an excess mortality risk (RR=1.8 (1.2-2.7), p=0.002; RR=1.6 (1.2-2.1), p=0.001; RR= 1.9 (1.3-2.9), p=0.001; RR=1.6 (1.2-2.1), p=0.02 respectively). However, only a high insulin level remained significant in a multivariable analysis (RR=1.54 (1.03-2.31), p=0.04) including baseline variables, left ventricular systolic function and in-hospital complications.
Conclusions: High fasting plasma insulin is an independent risk factor of all-cause mortality in non-diabetic patients with acute myocardial infarction. This justifies future intervention studies aiming at reducing insulin resistance and using fasting insulin as the target variable.