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Cardiovascular effects of prolonged growth hormone replacement in adults
S A Beshyah1, M Shahi, R Foale
1Unit of Metabolic Medicine, St Mary's Hospital and Medical School, London, UK.
Insights
Growth hormone (GH) replacement therapy in adults with hypopituitarism improved exercise tolerance over 6-18 months. This therapy did not significantly alter cardiac structure or systolic function in the study group.
Area of Science:
- Endocrinology
- Cardiovascular Medicine
- Metabolic Disorders
Background:
- Growth hormone (GH) deficiency in adults can lead to adverse cardiovascular changes.
- Understanding the impact of GH replacement therapy on cardiovascular health is crucial for managing hypopituitarism.
Purpose of the Study:
- To investigate the cardiovascular effects of biosynthetic human GH replacement therapy in adults with GH deficiency.
- To assess changes in exercise tolerance, cardiac structure, and function during GH therapy.
Main Methods:
- An open trial involving 34 hypopituitary patients receiving daily human GH (0.04 IU/kg) for 6-18 months.
- Evaluated resting blood pressure, exercise tolerance, renal function, and blood counts every 6 months.
- Utilized echocardiography and Doppler ultrasound to assess cardiac structure and function at baseline, 6, and 12 months.
Main Results:
- Significant increases in exercise time were observed at 6, 12, and 18 months (P < 0.001).
- No significant changes were found in resting or peak exercise blood pressure, heart rate, cardiac structure, ejection fraction, or cardiac output.
- A transient decrease in isovolumic relaxation time (a diastolic function marker) was noted at 6 months, but not at 12 months.
Conclusions:
- GH replacement therapy in hypopituitary adults leads to sustained improvements in exercise tolerance.
- The therapy did not induce adverse changes in cardiac structure or systolic function over the study period.
- GH therapy appears safe for cardiovascular parameters related to structure and systolic function in this population.
Objectives:
To study the cardiovascular effects of human growth hormone (GH) replacement therapy in adults.
Intervention:
Biosynthetic human GH given in a daily dose of 0.04 +/- 0.01 IU kg-1 for 6-18 months in an open trial.
Patients:
Thirty-four GH-deficient hypopituitary patients on conventional replacement therapy, aged 19-67 years and with a body mass index of 18.0-410.0 kg/m2.
Measurements:
Resting blood pressure, exercise tolerance, renal function and routine blood counts were assessed every 6 months. Two-dimensional echocardiography and Doppler ultrasound scanning were performed at 0, 6 and 12 months of GH therapy.
Results:
Exercise time increased significantly on GH from 9.37 +/- 2.64 min at the start to 10.39 +/- 2.86 min (P < 0.001), 10.90 +/- 2.48 min (P < 0.001) and 11.11 +/- 0.70 min (P < 0.001) at 6, 12 and 18 months respectively. There was no change in the heart rate or in the blood pressure at rest nor at the peak of exercise. No significant changes were observed in measures of cardiac structure (left ventricular mass index, left ventricular posterior wall thickness and interventricular septal thickness), ejection fraction nor in cardiac output. Isovolumic relaxation time, a marker of diastolic function, decreased in 24 patients after 6 months on GH (from 98.6 +/- 15.9 to 89.6 +/- 15.2 ms; P < 0.03) but it was not different from baseline in the 18 patients who were restudied at 12 months. There was no significant change in the left ventricular filling neither at 6 nor at 12 months. No significant, changes were observed in plasma electrolytes, creatinine nor in blood count on GH treatment.
Conclusions:
Growth hormone replacement therapy in hypopituitary adults for 6-18 months produced sustained increase in exercise tolerance but was not associated with changes in cardiac structure or systolic function.