Objective: Previous research revealed that a low concentration of serum insulin-like growth factor-1 (IGF-1) is associated with risks of myocardial infarction and heart failure. We hypothesized that the serum IGF-1 level affects clinical outcome in acute myocardial infarction (AMI). We examined the impact of serum IGF-1 in acute phase of AMI on 90-day mortality.
Patients and methods: In 54 patients with AMI, we measured serum total IGF-1 concentration on admission, in acute phase (1.9+/-0.5 days) and in chronic phase (28.5+/-6.7 days). We measured plasma brain natriuretic peptide (BNP), glucose and insulin in acute phase, and calculated insulin resistance (HOMA-R).
Results: Serum IGF-1 was 135.6+/-51.1 ng/ml on admission and significantly decreased to 105.5+/-42.2 ng/ml in acute phase, and then returned to baseline of 136.7+/-52.2 ng/ml in chronic phase. Five patients died of cardiac reasons within 90 days, all of whom had lower IGF-1 on admission and lower IGF-1 in acute phase than their median of 54 patients. Patients with the concentration of IGF-1 on admission below the median (<131 ng/ml) had significantly lower survival rate than those at or above the median (log-rank test p=0.0169). However, patients with BNP concentration at or above the median (> or =227 pg/ml) had a similar survival rate to those below the median (log-rank test p=0.6797). Multivariate analysis clarified that IGF-1 on admission was the sole independent predictor of 90-day mortality (p=0.007, risk ratio=0.927).
Conclusion: A low concentration of serum IGF-1 on admission was associated with a poor early prognosis of acute myocardial infarction.