Growth hormone deficiency and replacement in patients with treated Cushing's Disease, prolactinomas and non-functioning pituitary adenomas: effects on body composition, glucose metabolism, lipid status and bone mineral density

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.

Growth hormone (GH) deficiency and GH replacement therapy in patients previously treated for Cushing's disease

Several complications associated with active Cushing's disease may persist even years after complete and successful therapeutic remission of hypercortisolism. Growth hormone deficiency (GHD) shares many clinical features seen in patients with Cushing's disease, and its presence after disease remission (GHD-CR) might negatively influence and potentially worsen the systemic complications caused by previous hypercortisolism. GHD-CR is more prevalent in women, and compared to other causes of GHD, patients are younger at the onset of the pituitary disease, at diagnosis of GHD-CR and at start of GH therapy; prevalence of pituitary macroadenomas and visual abnormalities are lower, while prevalence of diabetes, hypertension, low bone mass, fractures, and worst quality of life, are higher. Serum IGF-1 levels are not useful for the diagnosis of GHD-CR and the application of GH stimulating tests requires some special attention in addition to the general recommendations for detecting GHD from other etiologies. In patients with active hypercortisolism, GH secretion is completely suppressed, but it may spontaneously and progressively recover over the years following successful therapy, meaning that GH testing may be performed at an appropriate time after remission for the correct diagnosis. Moreover, if the patient presents concomitant adrenal insufficiency, GH testing should only be carried out under adequate cortisol replacement therapy. GH therapy in children with GHD-CR improves adult height in the majority of patients, while GH therapy in adults has been associated with improvements in body composition, lipid profile and quality of life, but also with worsening of glucose metabolism.

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.

Fractures in pituitary adenoma patients from the Dutch National Registry of Growth Hormone Treatment in Adults

PURPOSE

The effects of growth hormone (GH) replacement therapy on fracture risk in adult GH deficient (GHD) patients with different etiologies of pituitary GHD are not well known, due to limited data. The aim of this study was to investigate characteristics and fracture occurrence at start of (baseline) and during long-term GH replacement therapy in GHD adults previously treated for Cushing's disease (CD) or acromegaly, compared to patients with previous nonfunctioning pituitary adenoma (NFPA).

METHODS

From the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide surveillance study in severe GHD adults, all patients using ≥30 days of GH replacement therapy with previous NFPA (n = 783), CD (n = 180) and acromegaly (n = 65) were selected. Patient characteristics, fractures and potential influencing factors were investigated.

RESULTS

At baseline, patients with previous CD were younger, more often female and had more often a history of osteopenia or osteoporosis, whereas patients with previous acromegaly had more often received cranial radiotherapy and a longer duration between treatment of their pituitary tumor and start of adult GH replacement therapy. During follow-up, a fracture occurred in 3.8 % (n = 39) of all patients. Compared to patients with previous NFPA, only patients with previous acromegaly had an increased fracture risk after 6 years of GH replacement therapy.

CONCLUSIONS

During GH replacement therapy, an increased fracture risk was observed in severe GHD adult patients previously treated for acromegaly, but not in those previously treated for CD, compared to severe GHD adult patients using GH replacement therapy because of previous NFPA. Further studies are needed to confirm these findings and to elucidate potential underlying mechanisms.

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.

Long-term remission and recurrence rates in Cushing's disease: predictive factors in a single-centre study

OBJECTIVE

To investigate the early and late outcomes of patients with Cushing's disease (CD) submitted to a neurosurgical procedure as first-line treatment.

DESIGN

In this single-centre retrospective case notes study, 131 patients with CD with a minimum follow-up period of 6 years (124 operated by transsphenoidal surgery (TSS) and seven by the transcranial approach) were studied. Apparent immediate cure: post-operative 0900 h serum cortisol level <50 nmol/l; remission: cortisol insufficiency or restoration of 'normal' cortisol levels with resolution of clinical features; and recurrence: dexamethasone resistance and relapse of hypercortisolaemic features.

RESULTS

In patients operated by TSS, remission of hypercortisolaemia was found in 72.8% of 103 microadenomas and 42.9% of 21 macroadenomas, with recurrence rates 22.7 and 33.3% respectively with a 15-year mean follow-up (range, 6-29 years). Of 27 patients with microadenomas operated after 1991, with positive imaging and pathology, 93% obtained remission with 12% recurrence. In multivariate analysis, the time needed to achieve recovery of hypothalamo-pituitaryadrenal axis was the only significant predictor of recurrence; all patients who recurred showed recovery within 3 years from surgery: 31.3% of patients had total hypophysectomy with no recurrence; 42% of patients with selective adenomectomy and 26.5% with hemi-hypophysectomy showed recurrence rates of 31 and 13% respectively (χ(2)=6.275, P=0.03). Strict remission criteria were not superior in terms of the probability of recurrence compared with post-operative normocortisolaemia.

CONCLUSIONS

Lifelong follow-up for patients with CD appears essential, particularly for patients who have shown rapid recovery of their axis. The strict criteria previously used for 'apparent cure' do not appear to necessarily predict a lower recurrence rate.

Treatment of Cushing disease: overview and recent findings

Endogenous Cushing syndrome is an endocrine disease caused by excessive secretion of adrenocorticotropin hormone in approximately 80% of cases, usually by a pituitary corticotroph adenoma (Cushing disease [CD]). It is a heterogeneous disorder requiring a multidisciplinary and individualized approach to patient management. The goals of treatment of CD include the reversal of clinical features, the normalization of biochemical changes with minimal morbidity, and long-term control without recurrence. Generally, the treatment of choice is the surgical removal of the pituitary tumor by transsphenoidal approach, performed by an experienced surgeon. Considering the high recurrence rate, other treatments should be considered. Second-line treatments include more radical surgery, radiation therapy, medical therapy, and bilateral adrenalectomy. Drug treatment has been targeted at the hypothalamic or pituitary level, at the adrenal gland, and also at the glucocorticoid receptor level. Frequently, medical therapy is performed before surgery to reduce the complications of the procedure, reducing the effects of severe hypercortisolism. Commonly, in patients in whom surgery has failed, medical management is often essential to reduce or normalize the hypercortisolemia, and should be attempted before bilateral adrenalectomy is considered. Medical therapy can be also useful in patients with CD while waiting for pituitary radiotherapy to take effect, which can take up to 10 years or more. So far, results of medical treatment of CD have not been particularly relevant; however, newer tools promise to change this scenario. The aim of this review is to analyze the results and experiences with old and new medical treatments of CD and to reevaluate medical therapies for complications of CD and hypopituitarism in patients with cured CD.

Clinical features of GH deficiency and effects of 3 years of GH replacement in adults with controlled Cushing's disease

OBJECTIVE

Patients in remission from Cushing's disease (CD) have many clinical features that are difficult to distinguish from those of concomitant GH deficiency (GHD). In this study, we evaluated the features of GHD in a large cohort of controlled CD patients, and assessed the effect of GH treatment.

DESIGN AND METHODS

Data were obtained from KIMS, the Pfizer International Metabolic Database. A retrospective cross-sectional comparison of background characteristics in unmatched cohorts of patients with CD (n=684, 74% women) and nonfunctioning pituitary adenoma (NFPA; n=2990, 39% women) was conducted. In addition, a longitudinal evaluation of 3 years of GH replacement in a subset of patients with controlled CD (n=322) and NFPA (n=748) matched for age and gender was performed.

RESULTS

The cross-sectional study showed a significant delay in GHD diagnosis in the CD group, who had a higher prevalence of hypertension, fractures, and diabetes mellitus. In the longitudinal, matched study, the CD group had a better metabolic profile but a poorer quality of life (QoL) at baseline, which was assessed with the disease-specific questionnaire QoL-assessment of GHD in adults. After 3 years of GH treatment (mean dose at 3 years 0.39 mg/day in CD and 0.37 mg/day in NFPA), total and low-density lipoprotein cholesterol decreased, while glucose and HbAlc increased. Improvement in QoL was observed, which was greater in the CD group (-6 CD group versus -5 NFPA group, P<0.01).

CONCLUSION

In untreated GHD, co-morbidities, including impairment of QoL, were more prevalent in controlled CD. Overall, both the groups responded similarly to GH replacement, suggesting that patients with GHD due to CD benefit from GH to the same extent as those with GHD due to NFPA.

Growth hormone (GH) replacement decreases serum total and LDL-cholesterol in hypopituitary patients on maintenance HMG CoA reductase inhibitor (statin) therapy

OBJECTIVE

Adult onset GH deficiency (GHD) is characterized by abnormalities of serum lipoprotein profiles and GH replacement results in favourable alterations in serum total and low density lipoprotein (LDL)-cholesterol. Preliminary evidence has indicated that the effect of GH replacement in this respect may be additive to that of HMG CoA reductase inhibitor (statin) therapy. We have examined this possibility during prospective follow-up of adult onset hypopituitary patients enrolled in KIMS (Pfizer International Metabolic Database), a pharmacoepidemiological study of GH replacement in adult hypopituitary patients.

DESIGN

Lipoprotein profiles were measured centrally at baseline and after 12 months GH replacement therapy.

PATIENTS

Sixty-one hypopituitary patients (30 male, 31 female) on maintenance statin therapy (mean 2.5 +/- 2.7 SD years before GH) (statin group - SG) and 1247 (608 male, 639 female) patients not on hypolipidaemic therapy (nonstatin group - NSG) were studied. All patients were naïve or had not received GH replacement during the 6 months prior to study. Patients who developed diabetes mellitus during the first year of GH therapy or in the subsequent year and those with childhood onset GHD were excluded from this analysis. An established diagnosis of diabetes mellitus was present in 18% SG and 4.4% NSG at baseline.

MEASUREMENTS

Serum concentrations of total, high density lipoprotein (HDL)-cholesterol, triglycerides and IGF-I were measured centrally in all patients and LDL-cholesterol was estimated using Friedewald's formula.

RESULTS

The relative frequency of various statin use was simvastatin 52% (15.8 +/- 8.1 mg, mean +/- SD), atorvastatin 30% (14.4 +/- 7.8 mg), pravastatin 9.8% (31.6 mg +/- 13.9 mg), lovastatin 6.6% (17.5 +/- 5 mg) and fluvastatin 1.6% (40 mg). Baseline serum total and LDL-cholesterol (mean +/- SD) were 5.2 +/- 1.4 and 3.1 +/- 1.3 mmol/l in SG and 5.8 +/- 1.2 and 3.7 +/- 1.0 mmol/l in NSG, respectively (P < 0.0001, SG vs. NSG). After 12 months GH replacement (SG: 0.32 +/- 0.17 mg/day; NSG: 0.38 +/- 0.1 mg/day) serum total and LDL-cholesterol decreased by a mean (+/-SD) of 0.48 (+/- 1.25) mmol/l (P < 0.0004) and 0.53 (+/- 1.08) mmol/l (P < 0.0001) in SG and by 0.30 (+/- 0.89) mmol/l (P < 0.0001) and 0.28 (+/- 0.80) mmol/l (P < 0.0001) in NSG, respectively. There were no significant changes in HDL-cholesterol or triglycerides in either group (SG vs. NSG: NS). A relationship between LDL-cholesterol at baseline and the decrease in LDL-cholesterol after 12 months GH was evident in both groups (SG: R = -0.54, P < 0.001; NSG: R = -0.4, P < 0.001) and a similar relationship for cholesterol was observed.

CONCLUSIONS

These data indicate that GH replacement exerts additional beneficial effects on lipoprotein profiles in patients on maintenance statin therapy, confirming that the effects of these interventions are complementary rather than exclusive.