Growth hormone therapy for hypopituitary adults: time for re-appraisal

The heart in growth hormone (GH) deficiency and the cardiovascular effects of GH

Besides its effects on longitudinal growth in childhood and its metabolic effects with consequences on body composition and lipid levels, growth hormone (GH) has important roles on maintaining the structure and function of the normal adult heart. GH/insulin like growth factor-I (IGF-I) also interacts with the vascular system and plays a role in the regulation of vascular tone. GH deficiency (GHD) in adulthood is associated with increased fat mass (particularly visceral) and abnormal lipid profile, which may contribute to the excess cardiovascular mortality observed in patients with panhypopituitarism. Treatment with GH improved body composition (by increasing lean mass and decreasing fat mass) and improved lipid profile. It also has beneficial effects on vascular walls. The improvement in cardiovascular morbidity and mortality induced by GH is less clear as data are scarce and obtained on small populations. The importance of alteration in cardiac morphology and function observed in GHD is debated, particularly when cardiac magnetic resonance is used rather than echocardiography. The effects of treatment with GH on heart function and morphology are modest when studied by echocardiography.

Abuse of growth hormone among young athletes

The underground abuse of growth hormone (GH) among young athletes presents a challenge to medical professionals. Health care professionals providing knowledgeable guidance regarding healthy ways to improve performance and appearance, as well as accurate information regarding substances' perceived benefits, risks, and unknown qualities, is invaluable to the young athlete. Further research focused on the profile and motivation of young people who use GH is essential to understanding and intervening better with those who use these substances.

N-terminal pro-B-type natriuretic peptide in patients with growth hormone disturbances

BACKGROUND

Acromegaly is associated with hypertrophic cardiomyopathy, hypertension and subsequent congestive heart failure. Impairment of cardiac function has also been associated with growth hormone deficiency (GHD). B-type natriuretic peptides (BNPs) have emerged as strong diagnostic and prognostic risk markers. They are cardioprotective hormones that compensate heart disease by promoting natriuresis and modulation of cardiac hypertrophy in response to volume expansion and ventricular wall stretch.

OBJECTIVE

To investigate N-terminal pro-BNP (NT-proBNP) in patients with GH disturbances before and after treatment, and in healthy gender- and age-matched controls.

SUBJECTS AND METHODS

Ten acromegalic patients (age 48 +/- 12 years) and 10 patients with GHD (age 41 +/- 14 years) were studied. None had symptoms or signs of cardiovascular disease except for hypertension. Serum NT-proBNP was measured before and 3, 6, 12 and 24 months after treatment.

RESULTS

Baseline NT-proBNP was lower in acromegalic patients [median (interquartile range) 24.3 (17.8-33.0) pg/ml] than in 20 healthy matched controls [57.9 (35.4-92.2) pg/ml; P < 0.001]. NT-proBNP increased during treatment (P = 0.002), concomitant with a decrease in IGF-I (P < 0.001). After 3 months of treatment NT-proBNP peaked, with a fourfold increase to 96.4 (57.8-113.2) pg/ml. NT-proBNP did not differ in patients with GHD compared with controls (P = 0.19), and did not change during treatment (P = 0.39).

CONCLUSION

Untreated patients with acromegaly had low NT-proBNP levels that increased fourfold after treatment. This is in contrast to other conditions with cardiac hypertrophy. Further studies are required to determine the significance of this novel finding in relation to acromegalic cardiac disease.

Physician decisions to discontinue long-term medications using a two-stage framework: the case of growth hormone therapy

BACKGROUND

Physician decisions to discontinue prescription medications for chronic conditions are fundamental determinants of drug use but have been inadequately studied. The decision to stop growth hormone (GH) therapy is an important example because of high cost (approximately $26,000/y for a 48-kg child), complexity of treatment options, and expansion of patient populations.

AIM

The aim of this study was to identify the factors that influence physician recommendations in the process of discontinuing therapy.

DESIGN

A random sample of half of U.S. pediatric endocrinologists (n = 265) was mailed a survey that included case scenarios of GH-deficient adolescents. Decision options involved a 2-stage framework to 1) initiate change in ongoing GH therapy (by discussing discontinuing GH with the family but not yet stopping treatment), and 2) take action to discontinue ongoing GH therapy (by terminating GH or reducing the dose to adult maintenance level).

MAIN OUTCOME MEASURE

Physician recommendations.

RESULTS

The response rate was 83.8%. Physiological indices of growth potential (growth velocity, bone age) significantly influenced discontinuation decisions (both P < 0.001). However, family preference, child's height, and physician attitudes exerted independent effects (each P < 0.05). Treatment price had little influence. Together, these variables accounted for 60% to 70% of the variation in recommendations. Their relative influence differed by stage in the discontinuation process.

CONCLUSION

The variables in our framework substantially explain discontinuation decisions. The data demonstrate the importance of both physiological and nonphysiological factors. The results suggest that physicians value even small gains as final height approaches, although an additional 20% expenditure may be needed to gain the last 1% to 3% of adult height.

The severity of growth hormone deficiency correlates with the severity of cardiac impairment in 100 adult patients with hypopituitarism: an observational, case-control study

In 100 patients with hypopituitarism and 80 sex- and age-matched healthy subjects, we correlated the severity of cardiac impairment to the severity of GH deficiency (GHD). By the GH peak after arginine plus GHRH test (normal > 16.5 microg/liter), the patients were classified as severe GHD (n = 56), partial GHD (n = 27), and non-GHD (n = 17). Compared with controls, decreased left ventricular ejection fraction at rest was found only in severe GHD patients (55.0 +/- 8.8 vs. 63.4 +/- 4.5%, P < 0.001); decreased left ventricular ejection fraction response on effort in severe (-4.6 +/- 17.4 vs. 15.2 +/- 9.1%, P < 0.001) and partial GHD patients (3.6 +/- 6.6 vs. 14.6 +/- 8.3%, P < 0.001); decreased diastolic filling at rest in severe (2.53 +/- 0.68 vs. 3.01 +/- 0.48 end-diastolic volume per second, P < 0.001) and partial GHD (2.61 +/- 0.45 vs. 2.89 +/- 0.54 end-diastolic volume per second, P = 0.004) patients; and decreased exercise duration and capacity in all the patient groups. A normal systolic performance on effort was found in 21.4% of severe GHD, 55.6% of partial GHD, all non-GHD, and 93.7% of controls. A normal diastolic filling at rest was found in 57.1% of severe GHD, 74.1% of partial GHD, 76.5% of non-GHD, and 90% of controls. In conclusion, cardiac performance is correlated with the GH status because significant impairment was found in patients with severe and partial GHD but not in non-GHD hypopituitary patients.

Growth hormone replacement for patients with adult onset growth hormone deficiency—what have we learned?

Growth hormone (GH) deficiency is a condition recognized to occur in individuals who have had multiple pituitary hormone deficiencies as a result of pathological processes or neurosurgical interventions. The indications, benefits, and risks of GH replacement therapy will be reviewed with an emphasis on those patients who were adults with the deficiency first emerged. The results of this analysis indicate that, although a measurable improvement can be detected in the patient's quality of life, body composition, and some cardiovascular parameters, the larger questions of long-term benefit and patient selection currently remain unanswered.

Cardiac effects of growth hormone in adults with growth hormone deficiency: a meta-analysis

BACKGROUND

Growth hormone (GH) treatment may improve morphological and functional cardiac parameters in adults with GH deficiency (GHD). However, clinical trials reported to date involved few patients and yielded variable effects.

METHODS AND RESULTS

We systematically reviewed blinded, placebo-controlled, randomized clinical trials of GH treatment in adults with GHD and open studies in patients with GHD before and after GH treatment, evaluating the effects of GH on cardiac parameters assessed by echocardiography. Sixteen trials (9 blinded and 7 open), involving a total of 468 patients, were identified in 3 bibliographic databases. GH dosage, duration of treatment, and study populations varied among the studies. We conducted a combined analysis of effects on left ventricular mass (LVM), interventricular septum thickness (IVS), left ventricular posterior wall (LVPW), left ventricular end-systolic (LVESD) and diastolic (LVEDD) diameters, stroke volume, E/A ratio, isovolumic relaxation time (IRT), and fractional shortening. Overall effect size was used to evaluate significance, and weighted mean difference between GH and control was given to appreciate size of the effect. GH treatment was associated with a significant increase in LVM: +10.8 (SD: 9.3) g (P=0.02); IVS: +0.28 (0.38) mm (P<0.001), LVPW: 0.98 (0.22) mm (P=0.05), LVEDD: +1.34 (1.13) mm (P<0.001), and stroke volume: +10.3 (8.7) mL (P<0.001). A trend toward a difference in fractional shortening was observed: +1.1 (1.1)% (P=0.06). Overall effect sizes were not significant for LVESD, E/A, and IRT.

CONCLUSIONS

GH treatment is associated with a significant positive effect on LVM, IVS, LVPW, LVEDD, and stroke volume, as assessed by echocardiography, in adults with GHD.

Human growth hormone replacement in adult hypopituitary patients: long-term effects on body composition and lipid status--3-year results from the HypoCCS Database

The Hypopituitary Control and Complications Study is an international surveillance study evaluating efficacy and safety of GH therapy of adult GH-deficient patients in clinical practice. The present report examined baseline data from 1,123 adult onset (AO) and 362 childhood onset (CO) patients, as well as efficacy in 242 patients who had completed 3 yr of GH treatment. At study entry, mean height, body mass index, waist to hip ratio, and lean body mass were significantly (P < 0.001 for each) lower in CO compared with AO patients. After 3 yr on GH, lean body mass was significantly increased in AO males and females and CO males but not CO females, whereas fat mass was significantly decreased in AO males only. Serum total cholesterol was decreased in females (-0.32 +/- 1.00 mmol/liter; P = 0.045) and males (-0.36 +/- 0.96 mmol/liter; P = 0.004). High-density lipoprotein (HDL) cholesterol was increased for females (0.10 +/- 0.26 mmol/liter; P = 0.026) and males (0.10 +/- 0.34 mmol/liter; P = 0.022). The low-density lipoprotein/HDL ratio was decreased in AO males (-0.93 +/- 2.00; P = 0.003), AO females (-0.65 +/- 0.74; P < 0.001), and CO females (-0.69 +/- 0.76; P = 0.038), but the decrease in CO males was not significant (-0.84 +/- 2.85; P = 0.273). In AO patients, lean body mass increase from baseline was greatest in the those younger than 40 yr old, less but still significant in the middle group (40-60 yr) and unchanged in older (>60 yr) patients; conversely, decreases in the low-density lipoprotein/HDL ratio were small and not significant in the younger patients but greater and significant in the middle and older age groups. During the 3-yr treatment, 114 (7.7%) patients discontinued, including 9 (0.6%) for tumor recurrences, 9 (0.6%) for neoplasia, and 9 (0.6%) for side effects. Therefore, these observational data showed significant long-term efficacy of adult GH replacement therapy on body composition and lipid profiles and indicate that age is an important predictor of response.

The cardiovascular risk of adult GH deficiency (GHD) improved after GH replacement and worsened in untreated GHD: a 12-month prospective study

Increased cardiovascular morbidity and mortality were reported in GH deficiency (GHD), and GH replacement can ameliorate cardiac abnormalities of adult GHD patients. To test the potential progression of untreated GHD on the cardiovascular risk and cardiac function, cardiovascular risk factors, cardiac size, and performance were prospectively evaluated in 15 GHD patients (age, 18-56 yr) who were treated with recombinant GH at the dose of 0.15-1.0 mg/d, 15 GHD patients (age, 18-56 yr) who refused GH replacement, and 30 healthy subjects (age, 18-53 yr). Electrocardiogram, systolic and diastolic blood pressure, and heart rate measurement, serum IGF-I, total cholesterol, low- and high-density lipoprotein (LDL, HDL) cholesterol, triglycerides, and fibrinogen level assay, echocardiography, and equilibrium radionuclide angiography were performed basally and after 12 months. At study entry, low IGF-I levels, unfavorable lipid profile, and inadequate cardiac and physical performance were found in GHD patients compared with controls. After 12 months of GH treatment, IGF-I levels normalized; HDL-cholesterol levels, left ventricular (LV) mass index (LVMi), left ventricular ejection fraction (LVEF) at peak exercise, peak filling rate, exercise duration and capacity significantly increased; total- and LDL-cholesterol levels significantly decreased. After 12 months in GH-untreated GHD patients, IGF-I levels remained stable, and HDL-cholesterol levels, LVEF both at rest and at peak exercise, and exercise capacity were further reduced; total- and LDL-cholesterol levels increased slightly. LVEF at rest and its response at peak exercise normalized in 60 and 53.3%, respectively, of GH-treated patients and in none of the GH-untreated patients. In conclusion, 12 months of GH replacement normalized IGF-I and improved lipid profile and cardiac performance in adult GHD patients. A similar period of GH deprivation induced a further impairment of lipid profile and cardiac performance. This finding strongly supports the need of GH replacement in adult GHD patients.