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/m2 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 microU/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.