Autonomic nervous system and cardiovascular risk assessment during one year of growth hormone (GH) replacement therapy in adults with GH deficiency

Abstract

oBJecTIve: This prospective study aimed to evaluate the impact of growth hormone deficiency (gHd) on cardiac autonomic tone and on cardiovascular risk and the changes after 12 months of gH replacement therapy (gHrT). gHd is associated with increased cardiovascular morbidity and mortality. This has been attributed to increased markers of cardiovascular risk and to abnormalities of both the cardiac and peripheral autonomic nervous systems. The autonomic cardiac nervous system (AcNs) can be indirectly evaluated by analysis of heart rate variability (Hrv) in clinostatism and orthostatism. desIgN: We compared 14 gHd patients at baseline and after 12 months of gHrT and 17 healthy controls. We analyzed a number of cardiovascular risk factors and we used analysis of Hrv during the Tilt Test that identified high frequency (HF) and low frequency (lF), representing parasympathetic and sympathetic activity, respectively. resUlTs: compared with the control group, in either clinostatism or in orthostatism our patients showed a significantly lower value of lF (P=0.047; P=0.004, respectively), whereas HF was significantly reduced in orthostatism (P=0.037), and indicatively in clinostatism (P=0.065). These values remained unchanged after 12 months of gHrT. No statistically significant differences were found between the lF/HF ratio in untreated and treated patients. In gHd patients, there was a significant reduction of cardiovascular risk in 12 months of replacement therapy (P=0.002). coNclUsIoNs: our study highlights the absence of sympathovagal imbalance in gHd patients; gHrT does not change AcNs during the first year of gH treatment but it reduces the absolute cardiovascular risk in these patients.

Effects of adult growth hormone deficiency and replacement therapy on the cardiometabolic risk profile

“…Studies using time-domain variables also found decreased sympathetic tone in adults with untreated GHD, which increased significantly with GHRT [ 178 , 181 ]. On the contrary, Boschetti et al did not detect symphathovagal imbalance in unreplaced patients, although, patients having GHD for more than 2 years were not included in the study [ 182 ]. Consequently, it cannot be excluded that patients untreated for more than 2 years may exhibit cardiac autonomic dysfunction [ 182 ].…”

“…On the contrary, Boschetti et al did not detect symphathovagal imbalance in unreplaced patients, although, patients having GHD for more than 2 years were not included in the study [ 182 ]. Consequently, it cannot be excluded that patients untreated for more than 2 years may exhibit cardiac autonomic dysfunction [ 182 ].…”

Long-term growth hormone (GH) replacement of adult GH deficiency (GHD) benefits the heart

“…Previous reports rarely indicated the therapeutic goals for the IGF-1 concentration (12,26,28,29,30,31,32,46). Only three publications (30,36,47) gave the mean achieved IGF-1 SDS or percentile of normal age-adjusted IGF-1 concentrations and none indicates the percentage of patients within this range. However, if the percentage of patients 'normalized' during GH-R is not indicated, the cardiological results may refer to patients with a broad range of treatment efficacy, some undertreated, others overtreated (28,32).…”

Interaction between cardiovascular autonomic control and sex hormones in perimenopausal women under menopausal hormone therapy

“…The relationship between MHT and cardiovascular autonomic control is poorly understood. The results of studies in this field are controversial [9][10][11][12][13][14][15][16][17].…”