Effects of growth hormone and insulin-like growth factor-1 on cardiac hypertrophy of hypertensive patients.

Objectives Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) interfere with cardiac mass (left ventricular mass; LVM) development. We investigated the role of the GH/IGF-1 axis on LVM and ventricular geometry in a group of 230 never-treated hypertensive patients. Methods Partition values for left ventricular hypertrophy (LVH) were 125 g/m 2 for both women and men. Insulin resistance was estimated by the homeostasis model assessment (HOMA) index. Results A significant inverse correlation was observed between IGF-1 and both fasting insulin (r=-0.249; P<0.0001) and GH (r= -0.218; P<0.0001). Systolic blood pressure (157.3 ± 13.6 versus 149.4 ± 12.8 mmHg; P< 0.001), fasting insulin (17.4 ± 8.5 versus 11.4 ± 6.0 μU/l; P<0.0001), HOMA (4.4 ± 2.3 versus 2.9 ± 1.6; P<0.0001) and GH (1.0±1.0 versus 0.4±0.5 ng/ml; P<0.0001) were significantly higher in patients with LVH; on the contrary, IGF-1 values (119.1 ± 47.8 versus 160.1 ± 75.5 ng/ml; P<0.0001) were higher in patients without LVH. In a logistic regression analysis, the strongest independent predictors of LVH were GH [relative risk (RR) = 2.078; 95% confidence interval (CI) = 1.364-3.163], HOMA (RR=1.345; 95% CI = 1.133-1.596), IGF-1 (RR = 0.993; 95% CI = 0.998-0.999) and systolic blood pressure (RR = 1.036; 95% CI = 1.013-1.060). IGF-1 showed an opposite trend in patients with eccentric and concentric hypertrophy. Conclusions Present data demonstrate that the increase in LVM prevalent in human essential hypertension is directly associated with serum GH levels and inversely related to circulating IGF-1.