Growth hormone replacement in adults and bone mineral density: a systematic review and meta-analysis

Differences between bone health parameters in adults with acromegaly and growth hormone deficiency: A systematic review

Preserving bone health is an important goal of care of patients with acromegaly and growth hormone deficiency (GHD). Both disorders are associated with compromised bone health and an increased risk of fracture. However, parameters of bone health that are routinely used to predict fractures in other populations, such as aBMD measured by DXA, are unreliable for this in acromegaly and GHD. Additional methodologies need to be employed to assess bone health in these patients. This review summarizes available data on the effects of acromegaly and GHD on parameters of bone health such as aBMD, volumetric bone mineral density (vBMD) and microarchitecture assessed by HRpQCT and other techniques, trabecular bone score (TBS) and fracture assessment. More research is needed to identify reliable predictors of fracture risk and to determine how best to screen for and treat those patients at risk so that bone health is optimized in these patients.

The influence of growth hormone deficiency on bone health and metabolisms

Growth hormone (GH) is a key peptide hormone in the regulation of bone metabolism, through its systemic and paracrine action mediated directly as well as by insulin-like growth factor-1 (IGF-1). Growth hormone exerts pleiotropic effects leading to an increase in linear bone growth, accumulation of bone mineral content and preservation of peak bone mass. Furthermore, it influences protein, lipid, and carbohydrate metabolism.Growth hormone deficiency (GHD) causes a low bone turnover rate leading to reduced bone mineral density (BMD) and increased bone fragility. The results of GH insufficiency are the most pronounced among children as it negatively affects longitudinal bone growth, causing short stature and in adolescents, in whom it hinders the acquisition of peak bone mass. Most studies show that treatment with recombinant human growth hormone (rhGH) in GHD patients could improve BMD and decrease fracture risk. This review aims to summarize the pathophysiology, clinical picture and management of bone complications observed in GHD.

Reduced Bone Mineral Density in Middle-Aged Male Patients with Adult Growth Hormone Deficiency

The aim of the work was to investigate the bone mineral density (BMD) in middle-aged male patients with both childhood-onset (CO) and adulthood-onset (AO) adult growth hormone deficiency (AGHD). In this retrospective cross-sectional study in a major medical center in China, dual X-ray absorptiometry was performed in 50 male AGHD patients (average age was 35.2±9.8 years) and 50 age- and BMI-matched non-athletic healthy men. BMD was compared between AGHD patients and controls. Compared with healthy controls, AGHD group had significantly decreased IGF-1 (p1<0.001) and IGF-1 SDS (p1<0.001). Serum testosterone levels were significantly lower in AGHD patients (p1<0.001), mainly in AO AGHD patients (p3<0.001). The BMD of the femoral neck, trochanter, femoral shaft, total hip, and lumbar spine were significantly lower in all AGHD patients compared with healthy controls (all p1<0.05), especially in CO AGHD patients (all p2<0.05). Multiple stepwise linear regression indicated AGHD was negatively correlated with BMD at each site (β<0, p<0.05). Additionally, serum testosterone level was an independent influencing factor of BMD of the femoral neck (β=0.256, p=0.018) and lumbar spine (β=0.219, p=0.040). BMD was significantly reduced in AGHD patients, especially in CO AGHD patients. Our data suggested that the status of growth hormone deficiency and testosterone level were important for maintaining of bone mineral density in middle-aged male patients with AGHD.

Bone and body composition analyses by DXA in adults with GH deficiency: effects of long-term replacement therapy

PURPOSE

The effects of growth hormone (GH) replacement on bone mass and body composition in adult with GH deficiency (AGHD) are still debated with regard to their persistence in the long term. Moreover, the impact of the gender on the response to GH is controversial. Aim of this study was to evaluate the long-term effects of rhGH replacement on bone mass and body composition in a monocentric cohort of patients with AGHD.

METHODS

Data from 118 patients with AGHD (34.8 ± 14.4 years, 43 women and 75 men) treated with rhGH for a period of at least 3 years up to a maximum of 10 were retrospectively collected. Bone mineral density (BMD) at the lumbar spine, femur, and 1/3 radius, and total and truncular body composition were evaluated by dual-energy X-ray absorption (DXA) before and during treatment. Clinical and laboratory evaluations were performed before and during the treatment period on an annual basis.

RESULTS

Lumbar spine BMD consistently increased in males, while it decreased in females after a transient improvement observed during the first 4 years of therapy. There were no significant changes in femoral and 1/3 radial BMD in either sexes. Lean mass significantly increased in both sexes, while fat mass only decreased in males.

CONCLUSIONS

In AGHD patients long-term rhGH replacement therapy induces a positive effect with regard to bone mass and body composition. A sexual dimorphism in the response to treatment is evident, with males displaying a more favorable outcome.

The Long-Term Effects of Growth Hormone Replacement on Bone Mineral Density and Trabecular Bone Score: Results of the 10-Year Prospective Follow-up

There are only few studies concerning about long-term effect of growth hormone (GH) replacement therapy on bone mineral density and bone microstructure. To assess effect of GH replacement therapy on bone mineral density (BMD) and trabecular bone score (TBS) in adult GH deficient (AGHD) subjects over period of 10 years. From 2005 to 2018, a prospective study of AGHD patients was conducted in national referral center for treatment of GHD. All patients received subcutaneous recombinant human GH in an IGF 1-normalizing regimen once a day. Lumbar spine (L-spine) and total hip (TH) BMD using Hologic densitometers were measured at baseline and every two years during treatment with rhGH. TBS was derived from L1-L4 DXA using iNsight® software (Medimaps, France) at each time point. Periods of measurement were baseline, year 2; 4; 6; 8 and 10. In total, 63 patients (38 males, 25 females, mean age 25.1±16 years) were included in the study. After 10 years of GH treatment, IGF-1 significantly increased (~35 %), with greatest increase at year 2. During 10-year follow-up, L-spine BMD increased approximately of 7 % (NS). TH BMD increase of 11 % during follow-up (p=0.0003). The greatest increment of BMD was achieved at year 6 on both sites, L-spine (+6 %) and TH BMD (+13 %) (p<0.05). There was no significant change of TBS during whole follow-up. In this study, sustaining positive effect of GH replacement therapy on bone density in subjects with adult GH deficiency over 10 years of follow-up was observed. The study did not show effect on TBS, as indirect measure of trabecular bone microarchitecture.

Advances in differential diagnosis and management of growth hormone deficiency in children

Growth hormone (GH) deficiency (GHD) in children is defined as impaired production of GH by the pituitary gland that results in growth failure. This disease might be congenital or acquired, and occurs in isolation or in the setting of multiple pituitary hormone deficiency. Isolated GHD has an estimated prevalence of 1 patient per 4000-10,000 live births and can be due to multiple causes, some of which are yet to be determined. Establishing the correct diagnosis remains key in children with short stature, as initiating treatment with recombinant human GH can help them attain their genetically determined adult height. During the past two decades, our understanding of the benefits of continuing GH therapy throughout the transition period from childhood to adulthood has increased. Improvements in transitional care will help alleviate the consequent physical and psychological problems that can arise from adult GHD, although the consequences of a lack of hormone replacement are less severe in adults than in children. In this Review, we discuss the differential diagnosis in children with GHD, including details of clinical presentation, neuroimaging and genetic testing. Furthermore, we highlight advances and issues in the management of GHD, including details of transitional care.

Update on vertebral fractures in pituitary diseases: from research to clinical practice

Derangement of pituitary hormone axes can induce changes in bone remodeling and metabolism with possible alterations in bone microarchitectural structure and increased susceptibility to fractures. Vertebral fractures (VFs), which are a hallmark of skeletal fragility, have been described in a very large number of patients with pituitary diseases. These fractures are clinically relevant, since they predispose to further fractures and may negatively impact on patients' quality of life. However, the management of skeletal fragility and VFs in the specific setting of pituitary diseases is a challenge, since the awareness for this disease is still low, prediction of VFs is uncertain, the diagnosis of VFs cannot be solely based on a clinical approach and also needs a radiological and morphometric approach, the risk of fractures may not be decreased via treatment of pituitary hormone disorders, and the effectiveness of bone-active drugs in this setting is not always evidence-based. This review is an update on skeletal fragility in patients with pituitary diseases, with a focus on clinical and therapeutic aspects concerning the management of VFs.

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.

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.

Deregulation of the growth hormone/insulin-like growth factor-1 axis in adults with cystic fibrosis

PURPOSE

Patients with cystic fibrosis (CF) present with signs and symptoms that overlap with those of adult growth hormone deficiency (GHD) syndrome: loss of muscle mass, bone fragility and lower stress tolerance. In literature, the prevalence of GHD in pediatric CF patients is higher than general population, but these studies have been performed on children with growth delay. To our knowledge, there are no studies on adult patients. The aim of this paper is to evaluate GH-IGF1 axis in an adult CF population.

METHODS

Fifty clinically stable adult patients, 30 males; age 36 ± 2 years; BMI 21.39 ± 0.22 kg/m² and FEV₁ 67 ± 4% were studied. Data regarding glycometabolic status and results of pituitary, thyroid, parathyroid, gonadal and adrenal function tests were recorded. All patients underwent a GH releasing hormone (GHRH) + Arginine stimulation test to confirm a GHD.

RESULTS

GHRH + Arginine test revealed the presence of GHD in 16 patients (32%); specifically 7 patients had a severe deficiency and 9 a partial deficiency.

CONCLUSIONS

Adult patients with CF may show GHD. These patients should be followed over time to assess if the GHD could impact the clinical progression of CF.

Design of the Growth hormone deficiency and Efficacy of Treatment (GET) score and non-interventional proof of concept study

BACKGROUND

The adverse effects of growth hormone (GH) deficiency (GHD) in adults (AGHD) on metabolism and health-related quality of life (HRQoL) can be improved with GH substitution. This investigation aimed to design a score summarising the features of GHD and evaluate its ability to measure the effect of GH substitution in AGHD.

METHODS

The Growth hormone deficiency and Efficacy of Treatment (GET) score (0-100 points) assessed (weighting): HRQoL (40%), disease-related days off work (10%), bone mineral density (20%), waist circumference (10%), low-density lipoprotein cholesterol (10%) and body fat mass (10%). A prospective, non-interventional, multicentre proof-of-concept study investigated whether the score could distinguish between untreated and GH-treated patients with AGHD. A 10-point difference in GET score during a 2-year study period was expected based on pre-existing knowledge of the effect of GH substitution in AGHD.

RESULTS

Of 106 patients eligible for analysis, 22 were untreated GHD controls (9 females, mean ± SD age 52 ± 17 years; 13 males, 57 ± 13 years) and 84 were GH-treated (31 females, age 45 ± 13 years, GH dose 0.30 ± 0.16 mg/day; 53 males, age 49 ± 15 years, GH dose 0.25 ± 0.10 mg/day). Follow-up was 706 ± 258 days in females and 653 ± 242 days in males. The GET score differed between the untreated control and treated groups with a least squares mean difference of + 10.01 ± 4.01 (p = 0.0145).

CONCLUSIONS

The GET score appeared to be a suitable integrative instrument to summarise the clinical features of GHD and measure the effects of GH substitution in adults. Exercise capacity and muscle strength/body muscle mass could be included in the GET score.

TRIAL REGISTRATION

NCT number: NCT00934063 . Date of registration: 02 July 2009.

Focus on growth hormone deficiency and bone in adults

Growth hormone (GH) exerts several effects on the skeleton, mediated either directly or indirectly, leading to increased bone formation and resorption rates. Patients with growth hormone deficiency (GHD) of adult onset have decreased bone mineral density (BMD) and increased fracture risk. Some, but not all, studies have found that adults with childhood onset GHD also have lower BMD than healthy controls. Adults with GHD of childhood onset have smaller bone dimensions, leading to possible underestimation of areal BMD (measured by dual energy X-ray absorptiometry), thus potentially confounding the interpretation of densitometric data. Available data suggest that patients with childhood onset GHD are at increased fracture risk. Prospective studies and some clinical trials found that GH replacement for at least 18-24 months leads to increased BMD. Retrospective and prospective data suggest that GH replacement is associated with decreased fracture risk in adults. However, data from randomized clinical trials are lacking.

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.

Effects of recombinant human growth hormone therapy on bone mineral density in adults with growth hormone deficiency: a meta-analysis

OBJECTIVE

GH deficiency is associated with decreased bone mineral density (BMD) and increased fracture risk. Because the effects of recombinant human GH (rhGH) therapy on BMD and bone mineral content have not been systematically investigated, we conducted a meta-analysis of pertinent studies.

DESIGN

A thorough search of the literature (MEDLINE, EMBASE, and the Cochrane Register) was performed. Relevant studies were divided and analyzed according to their design (randomized/controlled or prospective/retrospective) and duration of rhGH therapy (≤12 months and > 12 months).

RESULTS

Administration of rhGH led to a significant increase in lumbar spine (LS) and femoral neck (FN) BMD in randomized/controlled studies of more than 1 year [weighted mean difference (95% confidence interval)] of 0.038 g/cm(2) (0.011-0.065) and 0.021 g/cm(2) (0.006-0.037) at the LS and FN, respectively, and a nonsignificant drop at the same sites in studies of shorter duration. In prospective studies, a significant increase in the LS and FN BMD was obtained. On meta-regression, a negative association was observed between the change in LS and FN BMD and subjects' age and a positive association between the BMD change and treatment duration. In a subgroup analysis, the increase in LS and FN BMD was significant in men [0.048 g/cm(2) (0.033-0.064) and 0.051 g/cm(2) (0.003-0.098), respectively] but not in women.

CONCLUSION

This meta-analysis suggests a beneficial effect of rhGH replacement on BMD in adults with GH deficiency. This effect is affected by gender, age, and treatment duration. Larger studies are needed to evaluate the effect of rhGH on fracture risk.

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.

Pharmacophysiology of bone and spinal fusion

BACKGROUND CONTEXT

In recent years, the number of complex spinal surgeries has increased significantly in the elderly population, where the prevalence of low bone density is highest. Consequently, spine surgeons often treat osteoporotic patients who are associated with higher rates of instrumentation failure. Therefore, establishing a successful fusion requires an appropriate substrate for bone formation and local bone remodeling. The fusion process can be supported by therapies that seek to shift the balance of bone homeostasis to increased formation and reduced resorption.

PURPOSE

Thorough understanding of the physiology of bone formation and adjunctive therapies can help improve fusion rates. Therefore, we present a thorough review of the latest pharmacologic agents used to enhance bone strength and surgical spinal fusion.

METHODS

Systematic review of literature.

RESULTS

Current knowledge on bone physiology has led to the development of several pharmacologic agents that enhance bone formation and strengthen the human skeleton. At present, natural supplements of vitamin D and calcium or synthetic medications like bisphosphonates are widely used before and after spine surgeries to enhance bone fusion. Additional physiologic agents, including testosterone, parathyroid hormone, calcitonin, and growth hormone, have been shown to improve bone mass density or spinal fusion in both animal and human studies. As in other medical fields, gene therapy has shown viability and promise with the use of both viral and nonviral vectors.

CONCLUSIONS

Through the understanding of bone physiology, numerous natural and synthetic pharmacologic agents have been developed to enhance the body's skeleton and to improve outcomes of spinal fusion surgery.

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

OBJECTIVE

Little is known of the effects of long-term GH replacement on bone mineral content (BMC) and bone mineral density (BMD) in elderly GH-deficient (GHD) adults. DESIGN/PATIENTS/METHODS: In this prospective, single-center, open-label study, the effects of 3-year GH replacement were determined in 45 GHD patients >65 years and in 45 younger control GHD patients with a mean age of 39.5 (S.E.M. 1.1) years. All patients had adult-onset disease and both groups were comparable in terms of number of anterior pituitary hormonal deficiencies, gender, body mass index, and waist:hip ratio.

RESULTS

The mean maintenance dose of GH was 0.24 (0.02) mg/day in the elderly patients and 0.33 (0.02) mg/day in the younger GHD patients (P<0.01). The 3 years of GH replacement induced a marginal effect on total body BMC and BMD, whereas femur neck and lumbar (L2-L4) spine BMC and BMD increased in both the elderly and the younger patients. The treatment response in femur neck BMC was less marked in the elderly patients (P<0.05 vs younger group). However, this difference disappeared after correction for the lower dose of GH in the elderly patients using an analysis of covariance. There were no between-group differences in responsiveness in BMC or BMD at other skeletal locations.

CONCLUSIONS

This study shows that GH replacement increases lumbar (L2-L4) spine and femur neck BMD and BMC in younger as well as elderly GHD patients. This supports the notion that long-term GH replacement is also useful in elderly GHD patients.

Favorable long-term effects of growth hormone replacement therapy on quality of life, bone metabolism, body composition and lipid levels in patients with adult-onset growth hormone deficiency

OBJECTIVE

The goal of growth hormone (GH) replacement is to improve quality of life (QoL) and prevent the long-term complications of GH deficiency (GHD). Thirty-nine patients with adult-onset GH deficiency (AOGHD) who had originally participated in a randomized placebo-controlled crossover study involving treatment with either GH or placebo for nine months were enrolled in an open, 33-month follow-up study of the effects on QoL as well as bone and metabolic parameters.

METHODS

GH replacement was dosed individually to obtain IGF-I concentrations that were within the upper part of the normal range for age (mean+1SD). The variables were assessed on five occasions during the study.

RESULTS

QoL, as assessed by the sum scores of HSCL-58, AGHDA, physical activity (KIMS question 11) and the dimension vitality in SF-36, improved. Markers of bone formation and resorption remained increased throughout the study period. Bone mineral area (BMA), bone mineral content (BMC) and bone mineral density (BMD) increased in both the lumbar (L2-L4) spine and total body. BMC and BMD increased in the femur. Hypogonadal women however, showed reduced bone mass during the study period. The changes in body fat mass (BFM) and lean body mass (LBM) were sustained throughout the long-term treatment (BFM -2.18 (+/-4.87) kg LBM by 2.01(+/-3.25) kg). Low-density lipoprotein cholesterol (LDL-C) levels were reduced by 0.6 (+/-1.1) mmol/l, and high-density lipoprotein cholesterol (HDL-C) levels increased by 0.2 (+/-0.3) mmol/l. No changes were observed in body weight, fasting total cholesterol, triglycerides, HbA1c and plasma glucose. Mean fasting insulin levels increased significantly from 110 pmol/l to 159 pmol/l, p<0.02.

CONCLUSION

Long-term replacement of growth hormone in patients with AOGHD induces favorable effects on QoL as well as bone and metabolic parameters. An increase in insulin levels is also noteworthy.

Prevalence of growth hormone deficiency in adult polytransfused β-thalassemia patients and correlation with transfusional and chelation parameters

BACKGROUND

Dysfunction of GH-IGF-I axis has been described in many patients affected by β-thalassemia major (TM), especially in children and in adolescents. Recent studies have demonstrated the necessity to evaluate adult patients affected by TM to establish the presence of this alteration which could be relevant in the pathogenesis of cardiac and bone disease, frequently present in this hematological condition. The pathogenesis of this alteration, correlated in the past with iron overload, is not yet completely understood.

AIM

The aim of this paper is to evaluate GH-IGF-I axis in a group of adult polytransfused β-thalassemic patients (TM) and to correlate the results with transfusional and chelation parameters.

SUBJECTS AND METHODS

We performed an arginine plus GHRH stimulation test in 28 adult TM patients. Ferritin, IGF-I, liver enzymes, and liver iron concentration, assessed by a superconducting quantum interference device (SQUID) susceptometer were also determined. Moreover, in each patient we evaluated the bone status by a dual-energy X-ray absorptiometry study.

RESULTS

We found the presence of GH deficit in 9 patients (32.1%). There were no significant differences between the two groups regarding the value of ferritin, liver enzymes, and liver iron concentration, assessed by SQUID. The group affected by GH deficit showed a worse bone profile.

CONCLUSIONS

This study confirms the necessity to screen the status of GH/IGF-I axis in this group of patients, even in adult age. The presence of GH deficiency does not seem to be correlated with the efficacy parameters of transfusional and chelation therapy. Other mechanisms, additional to iron overload, could therefore play a role in the pathogenesis of this clinical condition. The presence of GH deficit seems to be very important on clinical aspects, like bone disease, that are crucial for quality of life in these patients.

Childhood growth hormone deficiency, bone density, structures and fractures: scrutinizing the evidence

Childhood-onset growth hormone deficiency (GHD) is frequently perceived to cause low bone density, fractures and osteoporosis. This article critically reviews the evidence behind these perceptions. Inherent limitations of current bone imaging techniques have caused many artefacts and misconceptions about bone density and structure. Using appropriate size-corrections, bone density is normal in children and adults with isolated GHD. Cortical density, trabecular density and trabecular volume are normal when measured by peripheral quantitative computerized tomography and histomorphometry. The only verifiable deficit affects cortical thickness (periosteal expansion), both in human and animal studies. However, short limb bones cannot be expected to have an average-sized shaft, as bone elongation and widening could be proportionally impaired in GHD. In addition, GH and IGF-1 have indisputable anabolic actions not only on bone, but also on muscle tissue. In fact, compared with all other bone-related variables, muscle size is the lowest at diagnosis of GHD. During GH therapy, muscle enlargement precedes and exceeds any gain in bone mass. The mechanostat theory suggests that the GHD-induced deficit in muscle force secondarily causes low cortical thickness. There is no evidence that isolated childhood-onset GHD, or severe GH resistance, causes an increased fracture risk in children or adults. Only adults with organic hypopituitarism appear to have a slightly greater risk of fractures. Using current transition guidelines, short children and adults with GHD are at risk of being misdiagnosed with low bone mass and may consequently receive inappropriate treatment. As neither reports of increased fracture risk nor low bone density can stand up against scrutiny, these misconceptions should no longer influence clinical practice. In this respect, GHD should not be listed as a cause of osteoporosis in children and there is a need to review current transition guidelines.

Impact of GH substitution on exercise capacity and muscle strength in GH-deficient adults: a meta-analysis of blinded, placebo-controlled trials

BACKGROUND

Several but not all trials suggest that GH replacement in GH-deficient adults improves aerobic exercise capacity, whereas its effect on muscle strength is more dubious. However, a denominator of these studies is a low sample size.

OBJECTIVE

We systematically reviewed and analysed all randomized, double-blind, placebo-controlled trials on the effects of GH administration on aerobic exercise capacity and muscle strength in GH-deficient adults.

STUDY SELECTION

Fifteen trials were identified from four databases. We conducted an analysis of effects on aerobic exercise capacity, performed on either a treadmill or a bicycle ergometer, muscle strength assessed by a dynamometer, and muscle mass assessed by computerized tomography.

RESULTS

The total number of patients included was 306 and the duration of treatment ranged from 3 to 12 months. GH replacement significantly increased aerobic exercise capacity [8.9 ± 0.8%, (P < 0.001)] including VO(2) max [0.17 ± 0.02 l/min (P < 0.001)], as well as muscle volume [7.1 ± 1.6%, (P < 0.001)]. In contrast, muscle strength measured in 113 patients was not significantly increased [3.2 ± 2.2% (P = 0.15)].

CONCLUSION

GH replacement in GH-deficient adults is associated with a significant positive effect on aerobic exercise capacity and muscle mass.

Treatment for 24 months with recombinant human GH has a beneficial effect on bone mineral density in young adults with childhood-onset GH deficiency

OBJECTIVE

Discontinuation of growth hormone (GH) therapy on completion of linear growth may adversely affect bone mineral density (BMD) in young adults with childhood-onset GH-deficiency (GHD). In the present study, we analyzed the impact of GH treatment on bone in young adults with GHD.

METHODS

BMD at the lumbar spine (L2-L4), total hip, and total body was measured at baseline and after 24 months in a cohort of young adults (18-25 years; n=160) with severe GHD treated with GH during childhood who were randomized to GH (n=109) or no treatment (n=51) in a multicenter, multinational, open-label study. GH starting doses (0.2 mg/day (males), 0.4 mg/day (females)) were increased after 1 month to 0.6 mg/day (males) and 0.9 mg/day (females) and then to 1.0 mg/day (males) and 1.4 mg/day (females) at 3 months for the remainder of the study.

RESULTS

After 24 months, lumbar spine BMD had increased significantly more in GH-treated patients than in controls (6 vs 2%; estimated treatment difference; 3.5% (95% confidence interval, 1.52-5.51) P<0.001). GH also had a significant positive effect on total hip BMD (P=0.015). Total body BMD was unchanged from baseline (P=0.315).

CONCLUSIONS

In young adults treated for childhood-onset GHD, there is a beneficial effect of continued GH treatment on BMD in adult life. Twenty-four months of GH treatment in these young adults was associated with an estimated 3.5% greater increase in BMD of the lumbar spine compared with controls.

Limited effects of growth hormone replacement in patients with GH deficiency during long-term cure of acromegaly

The aim of this study was to assess the effects of replacement with recombinant human growth hormone (rhGH) in patients with GH deficiency (GHD) after treatment of acromegaly. Intervention study. Sixteen patients (8 men, age 56 years), treated for acromegaly by surgery and radiotherapy, with an insufficient GH response to insulin-induced hypoglycaemia, were treated with 1 year of rhGH replacement. Study parameters were assessed at baseline and after 1 year of rhGH replacement. Study parameters were cardiac function, body composition, bone mineral density (BMD), fasting lipids, glucose, bone turnover markers, and Quality of Life (QoL). During rhGH replacement IGF-I concentrations increased from -0.4 +/- 0.7 to 1.0 +/- 1.5 SD (P = 0.001), with a mean daily dose of 0.2 +/- 0.1 mg in men and 0.3 +/- 0.2 mg in women. Nonetheless, rhGH replacement did not alter cardiac function, lipid and glucose concentrations, body composition or QoL. Bone turnover markers (PINP and beta crosslaps) levels increased (P = 0.005 and P = 0.021, respectively), paralleled by a small, but significant decrease in BMD of the hip. The beneficial effects of rhGH replacement in patients with GHD during cure from acromegaly are limited in this study.

Guidelines for the treatment of growth hormone excess and growth hormone deficiency in adults

The V Consensus Group Meeting on 'Guidelines for Treatment of GH Excess and GH Deficiency in the Adult' was an international workshop held on February 20-22, 2006 in Santa Monica, California, USA. The principal aim of this meeting was to provide guidelines for the evaluation and treatment of adults with either form of abnormal GH secretion: GH excess or GH deficiency. The workshop included debates as to the choice of primary treatment, discussions of the targets for adequate treatment, and concluded with presentations on open issues germane to adult GH treatment including the role of GH in malignancies, the impact of longterm treatment on bone, and a cost-benefit analysis. The meeting was comprised of 66 delegates representing 13 different countries.

Growth hormone, insulin-like growth factors, and the skeleton

GH and IGF-I are important regulators of bone homeostasis and are central to the achievement of normal longitudinal bone growth and bone mass. Although GH may act directly on skeletal cells, most of its effects are mediated by IGF-I, which is present in the systemic circulation and is synthesized by peripheral tissues. The availability of IGF-I is regulated by IGF binding proteins. IGF-I enhances the differentiated function of the osteoblast and bone formation. Adult GH deficiency causes low bone turnover osteoporosis with high risk of vertebral and nonvertebral fractures, and the low bone mass can be partially reversed by GH replacement. Acromegaly is characterized by high bone turnover, which can lead to bone loss and vertebral fractures, particularly in patients with coexistent hypogonadism. GH and IGF-I secretion are decreased in aging individuals, and abnormalities in the GH/IGF-I axis play a role in the pathogenesis of the osteoporosis of anorexia nervosa and after glucocorticoid exposure.

[Growth hormone deficiency in adulthood: how to diagnose and when to treat?]

Adult growth hormone deficiency (AGHD) is a well-established clinical entity with heterogeneous characteristics, in which the main causes are hypothalamus-pituitary tumors and/or their treatment. The diagnosis of ADGH should be considered in patients with a prior history of childhood-onset GH deficiency or a history of organic hypothalamus-pituitary disease. In these patients diagnosis is performed biochemically by provocative tests of GH secretion, once the measurement of the biological markers for GH action:IGF-l and IGFBP-3 levels, can be in the normal range in an important percentage of AGHD patients. The current treatment using an initial low dose of hrGH followed by individualised dose titration adjusted according to serum IGF-1 levels, leads to similar beneficial effects with less incidence of side effects, improved tolerance to treatment and a lower stable GH dose as compared to hrGH replacement therapy based on body weight or body surface area. As some patients might not profit from hrGH therapy, the potential beneficial effects of hrGH replacement therapy should be analyzed on individualized basis. Alternative available therapies with similar efficacy should be taken into consideration. Physical activity may improve body compostion, cardiovascular perfomance and well being in ADGH subjects not submitted to hrGH treatment. An important target of hrGH replacement therapy is its impact on quality of life, leading to social and professional improvement. Epidemiological evidence points to a decreasing life expectancy in ADGH patients but data regarding the impact of hrGH replacement on life expectancy are still lacking.

Effect of gonadal status on bone mineral density and radiological spinal deformities in adult patients with growth hormone deficiency

Growth hormone deficiency (GHD) in adult patients is associated with marked decrease in bone turnover, low bone mass and high risk of clinical and subclinical fractures. We investigated whether the prevalence of spinal deformities in adults with GHD was related to the gonadal status of patients. A total of 89 adult hypopituitary patients with severe GHD were evaluated for bone mineral density (BMD) and vertebral deformities (quantitative morphometric analysis). At the study entry, 54 patients were eugonadic whereas 35 patients were hypogonadic without replacement treatment. Radiological spinal deformities were found in 55 patients (61.8%) with higher prevalence in untreated (56 cases) versus treated (33 cases) GHD patients. Eugonadic and hypogonadic patients showed no significant difference in spinal deformities although T-score was significantly lower in hypogonadic as compared with eugonadic patients. Gonadal function was not correlated with the occurrence of spinal deformities which was instead inversely correlated with rhGH treatment. In conclusion, gonadal status may influence BMD in adult patients with GHD without affecting the risk to develop vertebral deformities. Conversely, rhGH replacement treatment seems to be the only factor influencing the risk to develop vertebral deformities in adult GHD patients.

Adult growth hormone deficiency: to treat or not to treat

In the last 15 years, it has been recognised that growth hormone deficiency (GHD) in the adult leads to increased morbidity (metabolic syndrome, osteoporosis, muscle wasting, impaired quality of life) and increased incidence of cardiovascular events, a main cause of the increased mortality observed in this population. Pituitary adenomas and their treatment (surgery, radiation) are the most common cause of GHD in adults. Patients with biochemical diagnosis of severe GHD must be offered growth hormone replacement therapy only in the presence of GHD associated morbidity. This treatment improves morbidity, but its effect on mortality remains to be proven. Continuation of treatment for GHD patients in late adolescence to early adulthood, who have reached final height with growth hormone replacement, requires careful clinical judgement.

Anterior pituitary hormone replacement therapy--a clinical review

This clinical review summarizes current approaches to diagnosis and treatment of anterior pituitary hormone deficiency. The diagnostic value of endocrine function tests and replacement strategies for hydrocortisone, thyroxine, sex steroids, and growth hormone replacement are reviewed. Female androgen deficiency syndrome and the current role of DHEA and testosterone replacement in women are also discussed.

Increased prevalence of radiological spinal deformities in adult patients with GH deficiency: influence of GH replacement therapy

This cross-sectional study shows that a high number of untreated adult patients with GHD develop radiological vertebral deformities. Patients undergoing GH replacement treatment showed a significantly lower prevalence of vertebral deformities versus treated patients in the presence of similar BMD, as assessed by DXA.

INTRODUCTION

In this cross-sectional study, we investigated whether the prevalence and degree of spinal deformities in adults with growth hormone deficiency (GHD) were related to the age of patients, degree of bone turnover, BMD, and recombinant human GH (rhGH) replacement therapy.

MATERIALS AND METHODS

One hundred seven adult hypopituitary patients (67 males and 40 females; mean age, 47 years; range: 16-81 years) with severe GHD and 130 control subjects (39 males, 91 females; mean age: 58.9 years; range: 26-82 years) were evaluated for BMD (DXA) and vertebral deformities (quantitative morphometric analysis). At study entry, 65 patients were on replacement therapy with rhGH, whereas 42 patients had never undergone rhGH.

RESULTS

Vertebral fractures were significantly more frequent in GHD patients versus control subjects (63.6% versus 37.7%; chi2 15.7; p < 0.001). The fracture prevalence, as well as the fracture number, was significantly higher in untreated versus treated patients (78.6% versus 53.8%; chi2: 6.7; p = 0.009), although the two groups of patients did not show any significant difference in median T score. In untreated GHD patients, the prevalence of vertebral deformities was correlated with T score (p = 0.002) and duration of disease (p = 0.003). In treated GHD patients, the prevalence of spinal deformities was correlated only with the timing of the beginning of rhGH replacement.

CONCLUSIONS

This cross-sectional study reports high prevalence of vertebral radiological deformities in adult patients with untreated GHD. The replacement treatment of GHD leads to a significant decrease in fracture rate.

Effect of growth hormone therapy and puberty on bone and body composition in children with idiopathic short stature and growth hormone deficiency

The state of bone health and the effect of growth hormone (GH) therapy on bone and body composition in children with idiopathic short stature (ISS) are largely unknown. A direct role of GH deficiency (GHD) on bone density is controversial. Using dual-energy X-ray absorptiometry, this study measured total body bone mineral content (TB BMC), body composition, and volumetric bone mineral density (vBMD) at the lumbar spine (LS) and femoral neck (FN) in 77 children (aged 3-17 years) with ISS (n = 57) and GHD (n = 20). Fifty-five children (GHD = 13) receiving GH were followed over 24 months including measurement of bone turnover. At diagnosis, size-corrected TB BMC SDS was greater (P <or= 0.002) and LSvBMD SDS lower (P < 0.03) than zero in both prepubertal ISS and GHD subjects, but FNvBMD SDS was reduced only in the GHD group (P < 0.05). The muscle-bone relation, as assessed by the BMC/lean mass (LTM) ratio SDS was not different between groups. During GH therapy, prepubertal GHD children gained more height (1.58 [0.9] SDS) and LTM (0.87 [0.63] SDS) compared to prepubertal ISS children (0.75 [0.27] and 0.17 [0.25] SDS, respectively). Percent body fat decreased in GHD (-5.94% [4.29]) but not in ISS children. Total body BMC accrual was less than predicted in all groups accompanied by an increase in bone turnover. Puberty led to the greatest absolute, but not relative, increments in weight, LTM, BMI, bone mass, and LSvBMD. Our results show that children with ISS and GHD differ in their response to GH therapy in anthropometry, body composition, and bone measures. Despite low vBMD values at diagnosis in both prepubertal groups, size-corrected regional or TB bone data were generally within the normal range and did not increase during GH therapy in GHD or ISS children. Growth hormone had great effects on the growth plate and body composition with subsequent gains in height, LTM, bone turnover, and bone mass accrual, but no benefit for volumetric bone density over 2 years.

Effects of 10 years of growth hormone (GH) replacement therapy in adult GH-deficient men

OBJECTIVE

GH-deficient adults have changes in body composition, bone mineral density (BMD) and lipid profile that can be altered by GH substitution. However, long-term data on GH substitution (up to 10 years of follow-up) are limited.

DESIGN

The effects of 10 years of GH replacement therapy on BMD, body composition, bone parameters, serum lipids and glucose metabolism were studied.

PATIENTS

Twenty-three childhood-onset GH-deficient men (mean age at baseline 28.6 years) were studied during 10 years of GH substitution therapy. A group of 19 age-matched healthy men served as a control group for BMD measurements at baseline and after 10 years.

RESULTS

BMD of the lumbar spine increased during the 10 years of GH therapy. Bone markers and BMD in the hip increased during the first 5 years of GH therapy, but were not different from baseline after 10 years. BMD changes over time in the lumbar spine and femoral neck were significantly different in the patients compared to the controls. After 10 years the difference between the groups had decreased, but BMD was still higher in the controls than in the patients. Lipid profile had improved after 10 years of GH therapy, but body mass index (BMI), waist-hip ratio (WHR), fasting glucose and glycosylated haemoglobin (HbA1c) had increased compared to baseline.

CONCLUSIONS

This long-term follow-up study found that 10 years of GH substitution in GH-deficient men causes sustained improvements in BMD in the lumbar spine and lipid profile but not in body composition.

Treatment of the adult growth hormone deficiency syndrome: directions for future research

The adult growth hormone deficiency syndrome (AGHD) is a well-defined clinical entity characterized by decreased lean body mass and bone mineral density, increased visceral adiposity, abnormal lipid profile, decreased muscle strength and exercise endurance, and diminished quality of life. Recent studies have emphasized the increased morbidity and mortality of hypopituitary patients, and there are now data implicating growth hormone (GH) deficiency as a cause of this increase. GH replacement therapy has been shown to reverse many of these abnormalities and to be well tolerated. Meta-analyses have demonstrated that GH treatment positively affects cardiovascular risk factors, and controlled trials have shown that visceral adiposity decreases in treated patients. Improvements in bone mineral density and decreases in fracture rates have also been reported, and new studies using disease-specific questionnaires provide convincing evidence that GH greatly enhances quality of life. Epidemiologic studies indicate that higher insulin-like growth factor I (IGF-I) levels may predict risk for certain cancers, but other studies suggest that lower IGF-I levels increase risk for ischemic heart disease. However, much of the community of endocrine caregivers remains skeptical of GH treatment and, therefore, a large fraction of patients with AGHD are not treated. The accumulation of long-term treatment data will be required to provide reassurance that GH treatment is a safe and necessary form of hormone replacement therapy for patients with AGHD.

Effects of 18-month of growth hormone (GH) replacement therapy in patients with Sheehan's syndrome

OBJECTIVE

Growth hormone deficiency (GHD) in adults is associated with abnormal body composition, altered lipid profile, reduced quality of life and osteoporosis. Replacement with recombinant GH results in significant improvements in most of these altered parameters. The most common cause of adult GHD in previous studies was due to pituitary tumors or their treatment. Sheehan's syndrome classically refers to postpartum hypopituitarism due to pituitary necrosis occurring secondary to massive bleeding at or just after delivery. While severe GHD is a well-established feature of Sheehan's syndrome, the effects of Growth hormone replacement therapy (GHRT) in these patients has not been extensively investigated. The present study was therefore designed to investigate the effects of GHD and GHRT in patients with Sheehan's syndrome.

DESIGN

The study comprised 14 severely GH-deficient patients with Sheehan's syndrome with a mean age of 49.4+/-7.9 yr. Treatment with GH was started at a dose of 0.15 mg per day in month 1, was increased to 0.30 mg per day in month 2, and was maintained at 0.66 mg per day until the end of month 18. With the similar maintenance dose adequate age adjusted IGF-I levels for each patient has been achieved. Blood pressure, lipid profile, biochemical parameters, anthropometric measurements including body mass index (BMI), waist and waist to hip ratio (W/H), and bone mineral density (BMD) were investigated before and at 3, 6, 12 and 18 months of the GHRT.

RESULTS

The duration of GHD from the onset of the disease was 19.4+/-1.6 yr. The majority of the patients (78%) had panhypopituitarism. At baseline mean total cholesterol, LDL-cholesterol and triglyceride levels were higher than the normal reference ranges but HDL-cholesterol levels were within the lower normal range. During the treatment period total cholesterol and LDL-cholesterol levels decreased and HDL-cholesterol levels increased significantly (P < 0.05). Waist circumference and waist to hip ratio were decreased significantly during the GHRT when compared to basal measurements (P < 0.05). There was a significant positive correlation between the basal waist circumference and the duration of GHD (P < 0.05).

CONCLUSIONS

This study clearly demonstrates that Sheehan's syndrome is characterized by severe and long-standing GHD. GHRT have beneficial effects in several parameters including lipid profile and waist circumference. But we could not observe any improvement in BMD after 18 months of GHRT. However interpretations of the present results need to be made with caution because of the uncontrolled design. Further placebo controlled studies with high number of patients with Sheehan's syndrome are warranted.