Effects of 3-year GH replacement therapy on bone mineral density in younger and elderly adults with adult-onset GH deficiency

Diagnosing and treating the elderly individual with hypopituitarism

Hypopituitarism in the elderly is an underestimated condition mainly due to the non-specific presentation that can be attributed to the effects of aging and the presence of comorbidities. Diagnosis and treatment of hypopituitarism often represent a challenging task and this is even more significant in the elderly. Diagnosis can be insidious due to the physiological changes occurring with aging that complicate the interpretation of hormonal investigations, and the need to avoid some provocative tests that carry higher risks of side effects in this population. Treatment of hypopituitarism has generally the goal to replace the hormonal deficiencies to restore a physiological balance as close as possible to that of healthy individuals but in the elderly this must be balanced with the risks of over-replacement and worsening of comorbidities. Moreover, the benefit of some hormonal replacement therapies in the elderly, including sex hormones and growth hormone, remains controversial.

Treating Hypopituitarism in the Over 65s: Review of Clinical Studies

The current increase of life expectancy is associated with the presence of endocrine diseases in the elderly. The management of hypopituitarism in this group of patients is a challenging task. A correct diagnosis, which represents an essential requisite for an appropriate medical treatment, can be difficult because of the physiological changes occurring in pituitary function with aging, which may lead to challenges in the interpretation of laboratory results. Furthermore, the treatment requires several careful considerations: the need to restore the hormonal physiology with replacement therapies must be balanced with the need to avoid the risks of the over-replacement, especially in the presence of concomitant cardiovascular and metabolic disease. Interactions with other drugs able to modify the absorption and/or the metabolism of hormonal replacement therapies should be considered, in particular for the treatment of hypoadrenalism and hypothyroidism. The most important challenges stem from the lack of specific studies focused on the management of hypopituitarism in older people.

Impact of Long-Term Growth Hormone Replacement Therapy on Metabolic and Cardiovascular Parameters in Adult Growth Hormone Deficiency: Comparison Between Adult and Elderly Patients

Growth hormone deficiency (GHD) in adults is due to a reduced growth hormone (GH) secretion by the anterior pituitary gland which leads to a well-known syndrome characterized by decreased cognitive function and quality of life (QoL), decreased bone mineral density (BMD), increased central adiposity with a reduction in lean body mass, decreased exercise tolerance, hyperlipidemia and increased predisposition to atherogenesis. Considering some similar features between aging and GHD, it was thought that the relative GH insufficiency of the elderly person could make an important contribution to the fragility of elderly. GH stimulation tests are able to differentiate GHD in elderly patients (EGHD) from the physiological reduction of GH secretion that occurs with aging. Although there is no evidence that rhGH replacement therapy increases the risk of developing Diabetes Mellitus (DM), reducing insulin sensitivity and inducing cardiac hypertrophy, long-term monitoring is, however, also mandatory in terms of glucose metabolism and cardiovascular measurements. In our experience comparing the impact of seven years of rhGH treatment on metabolic and cardiovascular parameters in GHD patients divided in two groups [adult (AGHD) and elderly (EGHD) GHD patients], effects on body composition are evident especially in AGHD, but not in EGHD patients. The improvements in lipid profile were sustained in all groups of patients, and they had a lower prevalence of dyslipidemia than the general population. The effects on glucose metabolism were conflicting, but approximately unchanged. The risk of DM type 2 is, however, probably increased in obese GHD adults with impaired glucose homeostasis at baseline, but the prevalence of DM in GHD is like that of the general population. The increases in glucose levels, BMI, and SBP in GHD negatively affected the prevalence of Metabolic Syndrome (MS) in the long term, especially in AGHD patients. Our results are in accordance to other long-term studies in which the effects on body composition and lipid profile are prominent.

Pathophysiology of growth hormone secretion disorders and their impact on bone microstructure as measured by trabecular bone score

This article is focused on endocrine-mediated osteoporosis caused by growth hormone (GH) disorders; adult GH deficiency and acromegaly. GH and insulin like growth factor-1 (IGF-1) stimulate linear bone growth through complex hormonal interactions and activates epiphyseal prechondrocytes. GH, via receptor activator of nuclear factor-kappaB (RANK), its ligand (RANK-L), and the osteoprotegerin system, stimulates production of osteoprotegerin and its accumulation in bone matrix. Malfunction of this mechanism, could lead to specific bone impairment. However, the primary problem of bone disease in GH secretion disorders is the primary prevention of osteoporotic fractures, so it is important to determine bone quality that better reflects the patient's actual predisposition to fracture. A method estimating bone quality from lumbar spine dual X-ray absorptiometry (DXA) scans is trabecular bone score (TBS). TBS in addition to bone mineral density (BMD) is a promising predictor of the osteoporotic fracture risk in women with postmenopausal osteopenia. In acromegaly TBS better defines risk of fracture because BMD is normal or even increased. TBS helps to monitor the effect of growth hormone therapy. Despite these findings, TBS should not be used alone, but a comprehensive consideration of all fracture risk factors, BMD and bone turnover markers is necessary.

Multi-centre phase IV trial to investigate the immunogenicity of a new liquid formulation of recombinant human growth hormone in adults with growth hormone deficiency

PURPOSE

To investigate whether a new liquid formulation of recombinant human growth hormone (r-hGH) induces the production of binding antibodies (BAbs) in adults with congenital or adult-onset growth hormone deficiency (GHD).

METHODS

Men or women aged 19-65 years with adult growth hormone deficiency who were r-hGH-naïve or had stopped treatment ≥ 1 month before screening were treated with between 0.15 and 0.30 mg/day r-hGH liquid formulation for 39 weeks. The primary endpoint was the proportion of patients who developed BAbs at any time. Secondary endpoints were the proportion of patients with BAbs who became positive for neutralising antibodies, the effects on biomarkers of r-hGH exposure, safety, and adherence to treatment downloaded from the easypod™ connect software.

RESULTS

Seventy-eight patients (61.5% men) with mean age 44.5 years (range 21-65) started and 68 (87.2%) completed the 39-week treatment period. 82.1% were treatment naïve; all were negative for BAbs to r-hGH at baseline. The median (interquartile range) duration of treatment [273 (267.0-277.0) days] was consistent with patients receiving the required doses, and mean treatment adherence measured using easypod™ connect was 89.3%. The proportion of patients who developed BAbs was 0% (95% confidence interval 0-4.68%) and biomarker profiles were consistent with exposure to r-hGH. 92.3% of patients reported ≥ 1 adverse event during treatment. Most events were mild or moderate and no new safety concerns were detected.

CONCLUSIONS

The low immunogenicity profile of the liquid formulation was consistent with that for the freeze-dried formulation, and no new safety concerns were reported.

Effects of Growth Hormone on Bone

PURPOSE

Describe the effects of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) on the skeleton.

FINDINGS

The GH and IGF-1 axis has pleiotropic effects on the skeleton throughout the lifespan by influencing bone formation and resorption. GH deficiency leads to decreased bone turnover, delayed statural growth in children, low bone mass, and increased fracture risk in adults. GH replacement improves adult stature in GH deficient children, increases bone mineral density (BMD) in adults, and helps to optimize peak bone acquisition in patients, during the transition from adolescence to adulthood, who have persistent GH deficiency. Observational studies suggest that GH replacement may mitigate the excessive fracture risk associated with GH deficiency. Acromegaly, a state of GH and IGF-1 excess, is associated with increased bone turnover and decreased BMD in the lumbar spine observed in some studies, particularly in patients with hypogonadism. In addition, patients with acromegaly appear to be at an increased risk of morphometric-vertebral fractures, especially in the presence of active disease or concurrent hypogonadism. GH therapy also has beneficial effects on statural growth in several conditions characterized by GH insensitivity, including chronic renal failure, Turner syndrome, Prader-Willi syndrome, postnatal growth delay in patients with intrauterine growth retardation who do not demonstrate catchup growth, idiopathic short stature, short stature homeobox-containing (SHOX) gene mutations, and Noonan syndrome.

SUMMARY

GH and IGF-1 have important roles in skeletal physiology, and GH has an important therapeutic role in both GH deficiency and insensitivity states.

Reviewing the safety of GH replacement therapy in adults

CONTEXT

Systematic data on safety of growth hormone (GH) replacement therapy in adult GH deficiency is lacking.

OBJECTIVE

To systematically describe safety of adult GH replacement therapy on glucose metabolism and long term safety.

DESIGN

A systematic web-based search of PubMed was performed guided by the Standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

OUTCOME

Randomised controlled trials of ≥3 months and open trials for ≥12 months with more than 50 adult patients (50 patient years, prospective and retrospective) including adverse event reporting as well as articles on mortality primarily on adult onset patients, reporting mortality ratios on GH treated patients, were included for the review.

RESULTS

Based on the defined selection criteria 94 studies were included. The short-term early placebo controlled trials did not demonstrate an increased frequency of diabetes mellitus (DM) and the long-term open studies did not consistently show an increased incidence of DM during GH replacement. The concern that long-term GH replacement might increase the risk of primary cancer, secondary neoplasia after tumour treatment and recurrence of previous tumours was not evident in the study data.

CONCLUSION

Based on available data, short- and long-term adult GH replacement in patients with severe GH deficiency and hypopituitarism is safe. However, the small number of subjects, limitation of long-term of GH treatment data and absence of an adequate control population is still a limitation for the interpretation of these data.

Multiple hormonal dysregulation as determinant of low physical performance and mobility in older persons

Mobility-disability is a common condition in older individuals. Many factors, including the age-related hormonal dysregulation, may concur to the development of disability in the elderly. In fact, during the aging process it is observed an imbalance between anabolic hormones that decrease (testosterone, dehydroepiandrosterone sulphate (DHEAS), estradiol, insulin like growth factor-1 (IGF-1) and Vitamin D) and catabolic hormones (cortisol, thyroid hormones) that increase. We start this review focusing on the mechanisms by which anabolic and catabolic hormones may affect physical performance and mobility. To address the role of the hormonal dysregulation to mobility-disability, we start to discuss the contribution of the single hormonal derangement. The studies used in this review were selected according to the period of time of publication, ranging from 2002 to 2013, and the age of the participants (≥65 years). We devoted particular attention to the effects of anabolic hormones (DHEAS, testosterone, estradiol, Vitamin D and IGF-1) on both skeletal muscle mass and strength, as well as other objective indicators of physical performance. We also analyzed the reasons beyond the inconclusive data coming from RCTs using sex hormones, thyroid hormones, and vitamin D (dosage, duration of treatment, baseline hormonal values and reached hormonal levels). We finally hypothesized that the parallel decline of anabolic hormones has a higher impact than a single hormonal derangement on adverse mobility outcomes in older population. Given the multifactorial origin of low mobility, we underlined the need of future synergistic optional treatments (micronutrients and exercise) to improve the effectiveness of hormonal treatment and to safely ameliorate the anabolic hormonal status and mobility in older individuals.

The exon 3 polymorphism of the growth hormone receptor is a severity-related factor for osteoporosis

The purpose of this study was to investigate the association between the GHR exon 3 fl/d3 polymorphism and body composition traits in Brazilian cohorts of normal post-menarche adolescent girls and in post-menopausal women with and without osteoporosis. First, multiplex PCR and quantitative PCR (TaqMan) were used with 105 DNA samples from the general Brazilian population to validate the SNP rs6873545 as a surrogate marker for the GHR polymorphism. Subsequently, genotyping was carried out to evaluate associations for this polymorphism in 136 post-menarche adolescents and 175 post-menopausal women, who were evaluated for body composition traits such as bone mineral density and fat-free mass. Statistical analysis used an independent sample t test, one-way ANOVA test and post hoc Tukey HSD test. Significant values were assumed by p < 0.05. Genotyping indicated complete linkage disequilibrium between the GHR polymorphism and the SNP alleles (r(2) = 1.0). Adolescents and healthy post-menopausal women showed no genotype associations for body composition traits or osteoporosis. However, a lower total body bone mineral density was observed in fl/fl post-menopausal women with osteoporosis (p = 0.0004). These results suggest that the SNP rs6873545 can be used as a surrogate for the GHR fl/d3 polymorphism due to linkage disequilibrium in the Brazilian population and that the fl/fl genotype is a severity-related risk factor for osteoporosis, but did not appear to be associated with disease status.

Impact of the growth hormone replacement on bone status in growth hormone deficient adults

INTRODUCTION

Growth hormone deficiency (GHD) is associated with reduced bone mineral density (BMD). GH replacement has positive effect on BMD but the magnitude of this effect and its mechanism are debated.

OBJECTIVES

The objectives of this study was first, to assess the effect of GH replacement on BMD, and second, to evaluate the effect of GH treatment on bone turnover and microarchitecture and to assess the factors influencing the effect of the therapy on BMD.

PATIENTS AND METHODS

Adult GHD (AO-GHD) and childhood onset GHD (CO-GHD) patients treated with GH using IGF-I normalization GH replacement regimen were prospectively followed during 2 years. Lumbar spine (L1-L4) and total femur BMD by Hologic discovery, in the subset of patients also bone turnover markers; osteocalcin and carboxy-terminal collagen crosslinks (CTx) were assessed at baseline and at months 3, 6, 12 and 24, respectively. The trabecular bone score (TBS) derived from lumbar spine DXA by the iNsight® software was assessed in a subset of study population at baseline and months 12 and 24.

RESULTS

In total, 147 GHD patients (age 35.1 years, 84 males/63 females, 43 of childhood onset GHD/104 AO-GHD) were included. BMD of lumbar spine and femur increased significantly during the treatment (14% and 7% increase at 2 years, respectively; p<0.0001). Bone markers increased during the first 12 months of treatment with subsequent decrease of CTx. At month 24, significant increase in TBS was observed (4%, p=0.02). BMD increase was significantly higher in males (15% increase in males vs. 10% in females, p=0.037) and childhood onset GHD (CO-GHD) patients (13% increase in CO-GHD, p=0.004).

CONCLUSION

GH supplementation leads to an increase of BMD with corresponding changes in bone turnover markers and changes in microarchitecture as assessed by trabecular bone score. Positive effect of GH on bone status is more pronounced in males and CO-GHD adults.

Predictors of the effects of 4 years of growth hormone replacement on bone mineral density in patients with adult-onset growth hormone deficiency - a KIMS database analysis

OBJECTIVE

Growth hormone (GH) replacement may increase bone mineral density (BMD) in GH-deficient (GHD) adults. The goal of this study was to identify predictors of BMD response to GH replacement in GH naïve adults.

DESIGN AND MEASUREMENTS

This was a retrospective analysis of data extracted from KIMS (Pfizer International Metabolic Database), an international pharmacoepidemiological survey of adult GHD patients from 31 countries.

PATIENTS

A total of 231 GH naive adults were identified (115 women and 116 men) who had BMD measured on the same densitometer in the lumbar spine (LS) and/or femoral neck (FN) both at baseline and after 4 years of GH replacement.

RESULTS

After 4 years, there was a median (10th, 90th percentile) 4·6% (-5·2%, 12·2%) increase in LS BMD over baseline (P = 0·0001). There was a positive correlation between per cent change in LS BMD and age at the onset of pituitary disease (r = 0·25, P = 0·001). There was no change in FN BMD over baseline [0·0% (-7·3%, 8·5%)]. On multivariate analysis, older age at the onset of pituitary disease predicted a greater increase in LS BMD on GH replacement (r = 0·55, P < 0·0001).

CONCLUSIONS

In a population of GH naïve adults, GH replacement led to a significant increase in LS BMD over baseline, but no change in FN BMD. The potential for greater BMD improvement on GH replacement therapy in adults with disease of later onset should be considered when making treatment decisions in this patient population.