Association of an impaired GH-IGF-I axis with cardiac wasting in patients with advanced cancer.

BACKGROUND: Growth hormone (GH) resistance is characterized by high GH levels but low levels of insulin-like growth factor-I (IGF-I) and growth hormone binding protein (GHBP) and, for patients with chronic disease, is associated with the development of cachexia. OBJECTIVES: We investigated whether GH resistance is associated with changes in left ventricular (LV) mass (cardiac wasting) in patients with cancer. METHODS: We measured plasma IGF-I, GH, and GHBP in 159 women and 148 men with cancer (83% stage III/IV). Patients were grouped by tertile of echocardiographic LVmass/height(2) (women, < 50, 50-61, > 61 g/m(2); men, < 60, 60-74, > 74 g/m(2)) and by presence of wasting syndrome with unintentional weight loss (BMI < 24 kg/m(2) and weight loss ≥ 5% in the prior 12 months). Repeat echocardiograms were obtained usually within 3-6 months for 85 patients. RESULTS: Patients in the lowest LVmass/height(2) tertile had higher plasma GH (median (IQR) for 1(st), 2(nd), and 3(rd) tertile women, 1.8 (0.9-4.2), 0.8 (0.2-2.2), 0.5 (0.3-1.6) ng/mL, p = 0.029; men, 2.1 (0.8-3.2), 0.6 (0.1-1.7), 0.7 (0.2-1.9) ng/mL, p = 0.003). Among women, lower LVmass was associated with higher plasma IGF-I (68 (48-116), 72 (48-95), 49 (35-76) ng/mL, p = 0.007), whereas such association did not exist for men. Patients with lower LVmass had lower log IGF-I/GH ratio (women, 1.60 ± 0.09, 2.02 ± 0.09, 1.88 ± 0.09, p = 0.004; men, 1.64 ± 0.09, 2.14 ± 0.11, 2.04 ± 0.11, p = 0.002). GHBP was not associated with LVmass. Patients with wasting syndrome with unintentional weight loss had higher plasma GH and GHBP, lower log IGF-I/GH ratio, and similar IGF-I. Overall, GHBP correlated inversely with log IGF-I/GH ratio (women, r =  - 0.591, p < 0.001; men, r =  - 0.575, p < 0.001). Additionally, higher baseline IGF-I was associated with a decline in LVmass during follow-up (r =  - 0.318, p = 0.003). CONCLUSION: In advanced cancer, reduced LVmass is associated with increased plasma GH and reduced IGF-I/GH ratio, suggesting increasing GH resistance, especially for patients with wasting syndrome with unintentional weight loss. Higher baseline IGF-I was associated with a decrease in relative LVmass during follow-up.