Bone microarchitecture and estimated bone strength in men with active acromegaly

Skeletal fragility in pituitary disease: how can we predict fracture risk?

Pituitary hormones play a crucial role in regulating skeletal physiology, and skeletal fragility is a frequent complication of pituitary diseases. The ability to predict the risk of fracture events is crucial for guiding therapeutic decisions; however, in patients with pituitary diseases, fracture risk estimation is particularly challenging. Compared to primary osteoporosis, the evaluation of bone mineral density by dual X-ray absorptiometry is much less informative about fracture risk. Moreover, the reliability of standard fracture risk calculators does not have strong validations in this setting. Morphometric vertebral assessment is currently the cornerstone in the assessment of skeletal fragility in patients with pituitary diseases, as prevalent fractures remain the strongest predictor of future fracture events. In recent years, new tools for evaluating bone quality have shown promising results in assessing bone impairment in patients with pituitary diseases, but most available data are cross-sectional, and evidence regarding the prediction of incident fractures is still scarce. Of note, apart from measures of bone density and bone quality, the estimation of fracture risk in the context of pituitary hyperfunction or hypofunction cannot ignore the evaluation of factors related to the underlying disease, such as its severity and duration, as well as the specific therapies implemented for its treatment. Aim of this review is to provide an up-to-date overview of all major evidence regarding fracture risk prediction in patients with pituitary disease, highlighting the need for a tailored approach that critically integrates all clinical, biochemical, and instrumental data according to the specificities of each disease.

Impact of medical therapy for hormone-secreting Pituitary tumors on bone

PURPOSE

Bone health is often impaired in patients with hormone-secreting pituitary tumors. Since medical therapy is central to their care, understanding how its use impacts on this is highly important.

METHODS

This review summarizes a systemmatic review of the literature on the effects of medical therapies for hormone-secreting pituitary tumors on bone.

RESULTS

In acromegaly, medical therapy lowers bone turnover marker (BTM) levels, consistent with correction of the high bone turnover of active disease, and overall, areal bone mineral density (aBMD) does not change or increases. Somatostatin-receptor ligand (SRL) and pegvisomant-treated acromegaly patients have persistently reduced volumetric BMD and microarchitectural abnormalities of the peripheral skeleton, deficits that are similar to those in surgically-treated patients. Fracture risk remains elevated in medically-treated acromegaly patients but in conjunction with biochemical control the risk is lessened. Treatment of prolactin-secreting tumors with dopamine agonists is associated with improvements in aBMD, but this does not always fully normalize despite effective medical treatment of the prolactinoma. In one cross-sectional study, prolactinoma patients had lower total volumetric BMD and impaired microarchitecture suggesting that bone microstructure does not fully normalize despite dopamine agonist therapy. Cross-sectional studies show a high rate of VF in patients with prolactin-secreting tumors that is lowered on cabergoline therapy, but still the fracture rate of men and postmenopausal women is higher than that of controls in some studies. Studies on the effects of modern-day medical therapy for Cushing's disease on bone are lacking.

CONCLUSION

More research is needed on the effectsof medical therapies for hormone secreting pituitary tumors on bone health.

Long-term Pegvisomant Therapy of Acromegaly: Effects on Bone Density, Turnover and Microstructure Using HRpQCT

Context

Fracture rate is increased in patients with active acromegaly and those in remission. Abnormalities of bone microstructure are present in patients with active disease and persist despite biochemical control after surgery. Effects of treatment with the GH receptor antagonist pegvisomant on bone microstructure were unknown.

Methods

We studied 25 patients with acromegaly (15 men, 10 women). In 20, we evaluated areal bone mineral density (BMD) by dual-energy X-ray absorptiometry and bone turnover markers (BTMs) longitudinally, before and during pegvisomant treatment. After long-term pegvisomant in 17, we cross-sectionally assessed volumetric BMD, microarchitecture, stiffness, and failure load of the distal radius and tibia using high-resolution peripheral quantitative computed tomography (HRpQCT) and compared these results to those of healthy controls and 2 comparison groups of nonpegvisomant-treated acromegaly patients, remission, and active disease, matched for other therapies and characteristics.

Results

In the longitudinal study, areal BMD improved at the lumbar spine but decreased at the hip in men after a median ∼7 years of pegvisomant. In the cross-sectional study, patients on a median ∼9 years of pegvisomant had significantly larger bones, lower trabecular and cortical volumetric density, and disrupted trabecular microarchitecture compared to healthy controls. Microstructure was similar in the pegvisomant and acromegaly comparison groups. BTMs were lowered, then stable over time.

Conclusion

In this, the first study to examine bone microstructure in pegvisomant-treated acromegaly, we found deficits in volumetric BMD and microarchitecture of the peripheral skeleton. BTM levels remained stable with long-term therapy. Deficits in bone quality identified by HRpQCT may play a role in the pathogenesis of fragility in treated acromegaly.

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.

Skeletal complications in acromegaly

Hypersecretion of growth hormone (GH) is rare and typically results from a pituitary functional tumor - somatotropinoma. It leads to excessive linear bone growth and manifests as gigantism if occurring in childhood and adolescence, before the closure of epiphyses or as a acromegaly in adulthood. The excess of GH impacts bone metabolism directly as well as indirectly through increased insulin-like growth factor 1 (IGF-1). In acromegaly as a consequence of overproduction of GH and IFG-1 and the influence of these hormones on bone osteoblasts, bone metabolism, growth and density increase. However, bone turnover is accelerated causing impaired bone microstructure and strength, which may lead to increased risk of vertebral fractures irrespective of normal bone mineral density. Apart from the changes in bone architecture, acromegaly also results in a degenerative joint disease of a different nature than primary osteoarthritis. Moreover, acromegaly leads to cardiovascular, metabolic and respiratory complications, and thus significantly impairs the quality of life. In this review, authors summarize the pathophysiology, diagnosis, and treatment of bone and joint disease in acromegaly.

Persistent Deficits in Bone Quality in Treated Acromegaly: Evidence From Assessments of Microstructure

Purpose

Fractures are increased in patients with acromegaly, both before and after successful acromegaly treatment. Abnormalities of bone microstructure, which may underlie this fragility, are present in active acromegaly but to what extent these improve with acromegaly treatment or persist despite biochemical remission remains unclear. To examine these questions, we studied the effects of acromegaly treatment and remission on bone quality.

Methods

Sixty-five women and men with acromegaly were studied. Subgroups underwent assessments of areal bone mineral density by dual x-ray absorptiometry, trabecular bone score (TBS), and volumetric bone mineral density, microarchitecture, stiffness and failure load of the distal radius and tibia by high-resolution peripheral quantitative tomography in a longitudinal study before and after acromegaly treatment and in a cross-sectional study in which patients were compared to sex-, age-, and body mass index-matched healthy controls.

Results

In the longitudinal study, significant increases in total, cortical, and trabecular densities at the radius and tibia and increased stiffness and failure load of the tibia occurred with acromegaly treatment. In the cross-sectional study, patients in biochemical remission after surgery had larger bones, lower trabecular and cortical volumetric density, and disrupted trabecular microarchitecture compared to controls. TBS did not change with acromegaly treatment but correlated with some microstructural parameters.

Conclusion

We show, for the first time, that volumetric bone mineral density and microarchitecture of the peripheral skeleton improve with acromegaly treatment but remain abnormal in patients in remission after surgery compared to controls. These abnormalities, known to be associated with fractures in other populations, may play a role in the pathogenesis of persistent fragility in treated acromegaly.

Bone quality in endocrine diseases: determinants and clinical relevance

PURPOSE

Bone is one of the main targets of hormones and endocrine diseases are frequent causes of secondary osteoporosis and fractures in real-world clinical practice. However, diagnosis of skeletal fragility and prediction of fractures in this setting could be a challenge, since the skeletal alterations induced by endocrine disorders are not generally captured by dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD), that is the gold standard for diagnosis of osteoporosis in the general population. The aim of this paper is to review the existing evidence related to bone quality features in endocrine diseases, proposing assessment with new techniques in the future.

METHODS

A comprehensive search within electronic databases was performed to collect reports of bone quality in primary hyperparathyroidism, hypoparathyroidism, hyperthyroidism, hypercortisolism, growth hormone deficiency, acromegaly, male hypogonadism and diabetes mellitus.

RESULTS

Using invasive and non-invasive techniques, such as high-resolution peripheral quantitative computed tomography or DXA measurement of trabecular bone score (TBS), several studies consistently reported altered bone quality as predominant determinant of fragility fractures in subjects affected by chronic endocrine disorders.

CONCLUSIONS

Assessment of skeletal fragility in endocrine diseases might take advantage from the use of techniques to detect perturbation in bone architecture with the aim of best identifying patients at high risk of fractures.

New tools for bone health assessment in secreting pituitary adenomas

Pituitary hormones regulate skeletal physiology, and excess levels affect bone remodeling and alter bone microstructure. Vertebral fractures (VFs) are an early phenomenon of impaired bone health in secreting pituitary adenomas. However, they are not accurately predicted by areal bone mineral density (BMD). Emerging data demonstrate that a morphometric approach is essential for evaluating bone health in this clinical setting and is considered to be the gold standard method in acromegaly. Several novel tools have been proposed as alternative or additional methods for the prediction of fractures, particularly in pituitary-driven osteopathies. This review highlights the novel potential biomarkers and diagnostic methods for bone fragility, including their pathophysiological, clinical, radiological, and therapeutic implications in acromegaly, prolactinomas, and Cushing's disease.

Determinants of skeletal fragility in acromegaly: a systematic review and meta-analysis

PURPOSE

Vertebral fractures (VFs) are a potential complication in acromegaly. However, the etiology of this skeletal fragility is unknown. This review aimed to evaluate the effect of acromegaly on VFs, bone turnover, areal bone mineral density (aBMD), and bone quality/microarchitecture. The effect of disease activity and gonadal status in these determinants of skeletal fragility was also evaluated.

METHODS

Articles published in English until September 6, 2020 on PubMed and Embase that reported at least one determinant of skeletal fragility in acromegalic patients, were included. Odds ratio (OR) to evaluate the risk of VFs and the standardized mean difference (SMD) to evaluate bone turnover, aBMD and bone quality/microarchitecture were calculated.

RESULTS

Fifty-eight studies met eligibility criteria, assembling a total of 2412 acromegalic patients. Of these, 49 studies were included in the meta-analysis. Acromegalic patients, when compared to non-acromegalic patients, had higher risk of VFs [OR 7.00; 95% confidence interval (CI) 2.80-17.52; p < 0.0001], higher bone formation (SMD 1.14; 95% CI 0.69-1.59; p < 0.00001), higher bone resorption (SMD 0.60; 95% CI 0.09-1.10; p = 0.02) and higher aBMD at the femoral neck (SMD 0.36; 95% CI 0.15-0.57; p = 0.0009). No significant differences were found regarding aBMD at lumbar spine. Considering the results of the different techniques evaluating bone quality/microarchitecture, the main reported alterations were a decrease in trabecular bone thickness and density, and an increase in trabecular separation. The presence of active disease and/or hypogonadism were associated with worst results.

CONCLUSION

Patients with acromegaly are at increased risk of VFs, mainly because of deterioration in bone microarchitecture.

Skeletal disorders associated with the growth hormone-insulin-like growth factor 1 axis

Growth hormone (GH) and insulin-like growth factor 1 (IGF1) are important regulators of bone remodelling and metabolism and have an essential role in the achievement and maintenance of bone mass throughout life. Evidence from animal models and human diseases shows that both GH deficiency (GHD) and excess are associated with changes in bone remodelling and cause profound alterations in bone microstructure. The consequence is an increased risk of fractures in individuals with GHD or acromegaly, a condition of GH excess. In addition, functional perturbations of the GH-IGF1 axis, encountered in individuals with anorexia nervosa and during ageing, result in skeletal fragility and osteoporosis. The effect of interventions used to treat GHD and acromegaly on the skeleton is variable and dependent on the duration of the disease, the pre-existing skeletal state, coexistent hormone alterations (such as those occurring in hypogonadism) and length of therapy. This variability could also reflect the irreversibility of the skeletal structural defect occurring during alterations of the GH-IGF1 axis. Moreover, the effects of the treatment of GHD and acromegaly on locally produced IGF1 and IGF binding proteins are uncertain and in need of further study. This Review highlights the pathophysiological, clinical and therapeutic aspects of skeletal fragility associated with perturbations in the GH-IGF1 axis.

Low sclerostin levels after long-term remission of acromegaly

PURPOSE

Bone health is compromised in acromegaly resulting in vertebral fractures (VFs), regardless of biochemical remission. Sclerostin is a negative inhibitor of bone formation and is associated with increased fracture risk in the general population. Therefore, we compared sclerostin concentrations between well-controlled acromegaly patients and healthy controls, and assessed its relationship with bone mineral density (BMD), and VFs in acromegaly.

METHODS

Seventy-nine patients (mean age 58.9 ± 11.4 years, 49% women) with controlled acromegaly, and 91 healthy controls (mean age 51.1 ± 16.9 years, 59% women) were included. Plasma sclerostin levels (pg/mL) in patients were measured with an ELISA assay, whereas in controls, serum levels were converted to plasma levels by multiplication with 3.6. In patients, VFs were radiographically assessed, and BMD was assessed using dual X-ray absorptiometry.

RESULTS

Median sclerostin concentration in controlled acromegaly patients was significantly lower than in healthy controls (104.5 pg/mL (range 45.7-234.7 pg/mL) vs 140.0 pg/mL (range 44.8-401.6 pg/mL), p < 0.001). Plasma sclerostin levels were not related to age, current growth hormone (GH) or insulin-like factor-1 (IGF-1) levels, gonadal state, treatment modality, remission duration, or BMD, VF presence, severity or progression.

CONCLUSION

Patients with long-term controlled acromegaly have lower plasma sclerostin levels than healthy controls, as a reflection of decreased osteocyte activity. Further longitudinal studies are needed to establish the course of sclerostin during different phases of disease and its exact effects in acromegalic osteopathy.

Trabecular bone score and bone mineral density in acromegalic osteopathy assessment: a cross-sectional study

PURPOSE

The evaluation of acromegalic osteopathy is a subject of current interest as there is a lack of evidence concerning proper evaluation techniques and clear diagnostic criteria. The aim of this study was to evaluate lumbar spine trabecular bone score (TBS) and bone mineral density (BMD) in acromegaly patients compared to healthy controls.

METHODS

We conducted a cross-sectional study on 43 acromegaly patients recruited between 2018 and 2020 and a healthy control group matched 1:1 for age, gender, and body mass index (BMI). All subjects underwent DXA, lumbar spine TBS, and bone turnover markers measurement.

RESULTS

Acromegaly patients showed significantly decreased lumbar spine TBS (1.244 ± 0.117 vs. 1.343 ± 0.124, p < 0.001) and no difference regarding BMD compared to control patients. In the subgroup analysis, TBS was significantly lower in both males and females (1.282 ± 0.075 vs. 1.366 ± 0.113, p = 0.01 and 1.222 ± 0.132 vs. 1.329 ± 0.130, p = 0.005) and, also, in hypogonadal and eugonadal acromegaly subjects compared to their healthy controls (1.231 ± 0.130 vs. 1.306 ± 0.125, p = 0.04 and 1.280 ± 0.065 vs. 1.381 ± 0.113, p = 0.008). Femoral neck BMD was higher in acromegalic hypogonadal patients [1.027 (IQR: 0.939-1.135) vs. 0.876 (IQR: 0.737-1.014), p = 0.004].

CONCLUSION

Our study indicates that TBS, but not BMD, is significantly decreased in acromegaly patients, regardless of gender and gonadal status. This data suggests that TBS could be a valuable tool in the assessment of acromegalic osteopathy.

Impaired Bone Microarchitecture in Premenopausal Women With Acromegaly: The Possible Role of Wnt Signaling

CONTEXT

Acromegaly can impair bone integrity, increasing the risk of vertebral fractures (VFs).

OBJECTIVE

To evaluate the impact of isolated GH/IGF-I hypersecretion on bone turnover markers, Wnt inhibitors, bone mineral density (BMD), microarchitecture, bone strength and vertebral fractures in female patients with acromegaly (Acro), compared with healthy control group (HC).

DESIGN, SETTING, AND PATIENTS

Cross-sectional study including 83 premenopausal women without any pituitary deficiency:18 acromegaly in remission (AcroR), 12 in group with active acromegaly (AcroA), and 53 HC. Serum procollagen type 1 N-terminal propeptide, β-carboxy-terminal crosslinked telopeptide of type 1 collagen, osteocalcin, sclerostin, and DKK1 were measured in blood samples. dual-energy X-ray absorptiometry, high-resolution peripheral quantitative computed tomography (HR-pQCT) and vertebral fractures evaluation were also assessed simultaneously.

MAIN OUTCOME AND RESULTS

AcroA showed significantly lower sclerostin and higher DKK1 compared with HC. On HR-pQCT of tibia and radius, Acro showed impairment of trabecular (area and trabecular number), increased cortical porosity, and increased cortical area and cortical thickness compared with HC. The only significant correlation found with HR-pQCT parameters was a positive correlation between cortical porosity and serum DKK1 (R = 0.45, P = 0.044). Mild VFs were present in approximately 30% of patients.

CONCLUSIONS

Eugonadal women with acromegaly without any pituitary deficiency showed increased cortical BMD, impairment of trabecular bone microstructure, and increased VF. Sclerostin was not correlated with any HR-pQCT parameters; however, DKK1 was correlated with cortical porosity in tibia (P = 0.027). Additional studies are needed to clarify the role of Wnt inhibitors on bone microarchitecture impairment in acromegaly.

Trabecular bone score and bone mineral density in patients with long-term controlled acromegaly

OBJECTIVE

Acromegaly is associated with increased vertebral fracture (VFs) risk not correlated to bone mineral density (BMD). Trabecular bone score (TBS), related to bone microarchitecture, provides information on bone strength. This cross-sectional study considered the usefulness of TBS and BMD to assess bone status in long-term controlled acromegalic patients.

DESIGN, PATIENTS, MEASUREMENTS

26 acromegaly patients (14 female and 12 males) were included in the study. A further 117 subjects were recruited as controls (58 females and 57 males). BMD was measured using dual-energy X-ray absorptiometry (DXA), TBS was obtained applying Medimaps software 2.0. Biochemical parameters were determined by standardized techniques.

RESULTS

73% of patients with acromegaly exhibited normal lumbar spine (LS) BMD. TBS was normal in 38% of acromegalic patients and partially degraded or degraded in 31% of patients, respectively. No differences were found in LS BMD between acromegalic patients and controls. TBS values were significantly lower in patients with acromegaly (1.27 ± 0.13 vs. 1.35 ± 0.17, p = .01). Postsurgical remission was associated with higher TBS values (1.35 ± 0.10 vs. 1.23 ± 0.13, p = .02) and pituitary radiotherapy treatment with lower TBS values (1.18 ± 0.12 vs. 1.31 ± 0.12, p = .004). On multivariate analysis, age, BMI and LS BMD were predictors of TBS changes in patients with acromegaly (p < .05).

CONCLUSIONS

Patients with long-term controlled acromegaly can exhibit deterioration of bone microstructure measured with TBS, despite BMD measurement not showing bone loss. Our study suggests that TBS is useful for monitoring the bone status changes in acromegalic patients.

When They're Done Growing, Don't Forget They May Still Need Growth Hormone

The effect of the growth hormone (GH) in promoting linear growth is well known; however, less recognized by practitioners especially pediatric, are its metabolic properties. This may be because the deleterious effects of improperly treated or untreated growth hormone deficiency (GHD) can present beyond the pediatric years. In addition, clinicians may lack familiarity with the potential issues that can arise due to inadequately treated GHD. Considering information from both the basic sciences research and clinical medicine, pediatric practitioners should be cognizant about the metabolic effects of GH. They should also be equipped to provide anticipatory guidance to patients regarding the importance of adherence to therapy in GHD and be prepared to transition patients with permanent GHD from pediatric GH supplementation to adult GH dosing. With a lack of proper transitioning, adverse outcomes may present beyond childhood.

3D DXA Hip Differences in Patients with Acromegaly or Adult Growth Hormone Deficiency

The skeleton is regulated by and responds to pituitary hormones, especially when the circulating levels are perturbed in disease. This study aims to analyse the between-group differences in 3D dual-energy X-ray absorptiometry (DXA) parameters at the hip site among patients with acromegaly or adult growth hormone deficiency (AGHD) and a healthy control group. The current cross-sectional study includes data for 67 adults, 20 with acromegaly, 14 with AGHD and 33 healthy controls. We obtained the areal bone mineral density (aBMD) outcomes using DXA and cortical and trabecular parameters using 3D-DXA software (3D-SHAPER). The mean-adjusted 3D-DXA parameters did not differ between acromegaly patients and the controls (p > 0.05); however, we found cortical bone impairment (−7.3% to −8.4%; effect size (ES) = 0.78) in AGHD patients (p < 0.05). Differences in the cortical bone parameters were more evident when comparing AGHD patients (−8.5% to −16.2%; ES = 1.22 to 1.24) with acromegaly patients (p < 0.05). In brief, the 3D mapping highlighted the trochanter as the site with greater cortical bone differences between acromegaly patients and the controls. Overall, AGHD patients displayed lower cortical parameters at the trochanter, femoral neck and intertrochanter compared to the controls and acromegaly patients. To sum up, 3D-DXA provided useful information about the characteristics of bone involvement in growth hormone (GH)-related disorders. Patients with AGHD showed distinct involvement of the cortical structure.

MRI-derived porosity index is associated with whole-bone stiffness and mineral density in human cadaveric femora

Ultrashort echo time (UTE) magnetic resonance imaging (MRI) measures proton signals in cortical bone from two distinct water pools, bound water, or water that is tightly bound to bone matrix, and pore water, or water that is freely moving in the pore spaces in bone. By isolating the signal contribution from the pore water pool, UTE biomarkers can directly quantify cortical bone porosity in vivo. The Porosity Index (PI) is one non-invasive, clinically viable UTE-derived technique that has shown strong associations in the tibia with μCT porosity and other UTE measures of bone water. However, the efficacy of the PI biomarker has never been examined in the proximal femur, which is the site of the most catastrophic osteoporotic fractures. Additionally, the loads experienced during a sideways fall are complex and the femoral neck is difficult to image with UTE, so the usefulness of the PI in the femur was unknown. Therefore, the aim of this study was to examine the relationships between the PI measure in the proximal cortical shaft of human cadaveric femora specimens compared to (1) QCT-derived bone mineral density (BMD) and (2) whole bone stiffness obtained from mechanical testing mimicking a sideways fall. Fifteen fresh, frozen whole cadaveric femora specimens (age 72.1 ± 15.0 years old, 10 male, 5 female) were scanned on a clinical 3-T MRI using a dual-echo UTE sequence. Specimens were then scanned on a clinical CT scanner to measure volumetric BMD (vBMD) and then non-destructively mechanically tested in a sideways fall configuration. The PI in the cortical shaft demonstrated strong correlations with bone stiffness (r = -0.82, P = 0.0014), CT-derived vBMD (r = -0.64, P = 0.0149), and with average cortical thickness (r = -0.60, P = 0.0180). Furthermore, a hierarchical regression showed that PI was a strong predictor of bone stiffness which was independent of the other parameters. The findings from this study validate the MRI-derived porosity index as a useful measure of whole-bone mechanical integrity and stiffness.

A Consensus on the Diagnosis and Treatment of Acromegaly Comorbidities: An Update

OBJECTIVE

The aim of the Acromegaly Consensus Group was to revise and update the consensus on diagnosis and treatment of acromegaly comorbidities last published in 2013.

PARTICIPANTS

The Consensus Group, convened by 11 Steering Committee members, consisted of 45 experts in the medical and surgical management of acromegaly. The authors received no corporate funding or remuneration.

EVIDENCE

This evidence-based consensus was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence following critical discussion of the current literature on the diagnosis and treatment of acromegaly comorbidities.

CONSENSUS PROCESS

Acromegaly Consensus Group participants conducted comprehensive literature searches for English-language papers on selected topics, reviewed brief presentations on each topic, and discussed current practice and recommendations in breakout groups. Consensus recommendations were developed based on all presentations and discussions. Members of the Scientific Committee graded the quality of the supporting evidence and the consensus recommendations using the GRADE system.

CONCLUSIONS

Evidence-based approach consensus recommendations address important clinical issues regarding multidisciplinary management of acromegaly-related cardiovascular, endocrine, metabolic, and oncologic comorbidities, sleep apnea, and bone and joint disorders and their sequelae, as well as their effects on quality of life and mortality.

Exon 3-deleted growth hormone receptor isoform is not related to worse bone mineral density or microarchitecture or to increased fracture risk in acromegaly

PURPOSE

Acromegaly is a cause of secondary osteoporosis and is associated with increased risk of vertebral fractures (VFs). The influence of exon 3-deleted isoform of growth hormone receptor (d3-GHR) on bone microarchitecture has not been studied in acromegaly.

AIM

The aim of this study was to analyze the associations between d3-GHR isoform and bone mineral density (BMD), bone microarchitecture, and VFs in acromegaly patients.

METHODS

Consecutive acromegaly patients treated at a single reference center were included. BMD was analyzed using dual-energy X-ray absorptiometry (DXA) and bone microarchitecture was analyzed by high-resolution peripheral quantitative computed tomography (HR-pQCT). The presence of moderate to severe VFs was assessed by thoracic and lumbar X-ray. GHR genotyping was analyzed by PCR, and full-length isoform of GHR (fl-GHR) was represented by a 935-bp fragment and d3-GHR by a 532-bp fragment.

RESULTS

Eighty-nine patients were included [56 females; median age at diagnosis: 43 years (17-78)]. Disease was uncontrolled in 63% of patients. At least one d3-GHR allele was present in 60% of patients. Frequency of active disease (p = 0.276) and hypogonadism (p = 1.000) was not different between patients with fl-GHR and those with at least one d3-GHR. There was no difference in any DXA or HR-pQCT parameters between patients with fl-GHR and those with d3-GHR. Significant VFs were observed in 14% of patients, but there was no difference in frequency between patients with fl-GHR and those with at least one d3-GHR allele (p = 0.578).

CONCLUSIONS

Presence of d3-GHR was not associated with worse BMD or bone microarchitecture or with higher frequency of significant VFs.

Effects of 24 Weeks of Growth Hormone Treatment on Bone Microstructure and Volumetric Bone Density in Patients with Childhood-Onset Adult GH Deficiency

OBJECTIVE

Adults with childhood-onset growth hormone deficiency (CO AGHD) have prominently impaired volumetric bone density (vBMD) and bone microarchitecture. Effects of recombinant human growth hormone (rhGH) on bone microarchitecture in CO AGHD were insufficiently evaluated. The objective of this study is to assess the effects of rhGH on bone microarchitecture and vBMD in CO AGHD patients.

DESIGN

In this single-center prospective study, nine CO AGHD patients received rhGH treatment for 24 weeks. High-resolution peripheral quantitative computerized tomography (HR-pQCT) of distal tibia and radius was performed at baseline and at the end of treatment. Main outcomes were vBMD and morphometric parameters from HR-pQCT.

RESULTS

After 24-week treatment, IGF-1 SDS gradually increased from -3.31 ± 1.56 to -1.92 ± 1.65 (p=0.113). Serum phosphate (1.17 ± 0.17 vs. 1.35 ± 0.18 mmol/L, p=0.030), alkaline phosphatase (83.6 ± 38.6 vs. 120.5 ± 63.7, p=0.045), and β-CTX (0.67 ± 0.32 vs. 1.09 ± 0.58, p=0.022) were significantly elevated. In distal tibia, total vBMD (200.2 ± 41.7 vs 210.3 ± 40.9 mg HA/cm³, p=0.017), cortical area (89.9 ± 17.7 vs 95.5 ± 19.9 mm², p=0.032), and cortical thickness (0.891 ± 0.197 vs 0.944 ± 0.239 mm, p=0.028) were significantly improved. Trabecular area decreased from 795.3 ± 280.9 to 789.6 ± 211.4 mm² (p=0.029). Trabecular bone volume fraction increased from 0.193 ± 0.038 to 0.198 ± 0.036 (p=0.027). In radius, cortical perimeter (74.1 ± 10.0 vs 75.0 ± 10.9 mm, p=0.034), trabecular thickness (0.208 ± 0.013 vs 0.212 ± 0.013 mm, p=0.008), trabecular separation (0.743 ± 0.175 vs 0.796 ± 0.199 mm, p=0.019), and inhomogeneity of network (Tb.1/N.SD) (0.292 ± 0.087 vs 0.317 ± 0.096 mm, p=0.026) were significantly improved, while trabecular number (1.363 ± 0.294 vs 1.291 ± 0.325 1/mm, p=0.025) decreased significantly.

CONCLUSIONS

Our results provide evidence for improvement of vBMD and bone microarchitecture in AGHD patients at a relatively early stage of rhGH treatment.

Hip Structure Analyses in Acromegaly: Decrease of Cortical Bone Thickness After Treatment: A Longitudinal Cohort Study

Long‐standing growth hormone (GH) excess causes the skeletal clinical signs of acromegaly with typical changes in bone geometry, including increased cortical bone thickness (CBT). However, a high prevalence and incidence of vertebral fractures has been reported. The aim of this study was to assess the course of cortical bone dimensions in the hip by comparing patients with acromegaly and clinically nonfunctioning pituitary adenomas (NFPAs) at baseline and 1 year after pituitary surgery (1‐year PO) in a longitudinal cohort study. DXA was performed in patients with acromegaly (n = 56) and NFPA (n = 47). CBT in the femoral neck (CBTneck), calcar (CBTcalcar), and shaft (CBTshaft) were determined by hip structural analysis (HSA). CBT at baseline and the change to 1‐year PO were compared. Test results were adjusted for differences in gender distribution, age, and gonadal status. Cortical thickness analyses showed higher values [mm] at baseline in patients with acromegaly compared with NFPA: CBTneck median [25th; 75th] 6.2 [4.7; 8.0] versus 5.1 [4.1; 6.4] (p = 0.006), CBTcalcar 4.8 [4.2, 5.7] versus 4.0 [3.2, 4.5] (p < 0.001), CBTshaft 6.2 [5.1, 7.2] versus 5.2 [4.6, 6.0], (p = 0.003). In acromegaly, GH was correlated with CBTneck (r = 0.31, p = 0.020), whereas IGF‐1 was correlated with CBTcalcar (r = 0.39, p = 0.003) at baseline. In acromegaly, CBTneck decreased by 11.2%, p = 0.002 during follow‐up. Finally, the decrease in CBTneck and CBTcalcar in acromegaly was significant compared with NFPA (p = 0.023 and p = 0.017, respectively). Previous observations of increased CBT in acromegaly were confirmed with DXA‐derived HSA in a large, well‐defined cohort. The decline in CBT in acromegaly could contribute to the increased fracture risk in acromegaly despite increased bone dimensions and disease control. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF GROWTH HORMONE DEFICIENCY IN ADULTS AND PATIENTS TRANSITIONING FROM PEDIATRIC TO ADULT CARE

Objective: The development of these guidelines is sponsored by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPG). Methods: Recommendations are based on diligent reviews of clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols. Results: The Executive Summary of this 2019 updated guideline contains 58 numbered recommendations: 12 are Grade A (21%), 19 are Grade B (33%), 21 are Grade C (36%), and 6 are Grade D (10%). These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world care of patients. The evidence base presented in the subsequent Appendix provides relevant supporting information for the Executive Summary recommendations. This update contains 357 citations of which 51 (14%) are evidence level (EL) 1 (strong), 168 (47%) are EL 2 (intermediate), 61 (17%) are EL 3 (weak), and 77 (22%) are EL 4 (no clinical evidence). Conclusion: This CPG is a practical tool that practicing endocrinologists and regulatory bodies can refer to regarding the identification, diagnosis, and treatment of adults and patients transitioning from pediatric to adult-care services with growth hormone deficiency (GHD). It provides guidelines on assessment, screening, diagnostic testing, and treatment recommendations for a range of individuals with various causes of adult GHD. The recommendations emphasize the importance of considering testing patients with a reasonable level of clinical suspicion of GHD using appropriate growth hormone (GH) cut-points for various GH-stimulation tests to accurately diagnose adult GHD, and to exercise caution interpreting serum GH and insulin-like growth factor-1 (IGF-1) levels, as various GH and IGF-1 assays are used to support treatment decisions. The intention to treat often requires sound clinical judgment and careful assessment of the benefits and risks specific to each individual patient. Unapproved uses of GH, long-term safety, and the current status of long-acting GH preparations are also discussed in this document. LAY ABSTRACT This updated guideline provides evidence-based recommendations regarding the identification, screening, assessment, diagnosis, and treatment for a range of individuals with various causes of adult growth-hormone deficiency (GHD) and patients with childhood-onset GHD transitioning to adult care. The update summarizes the most current knowledge about the accuracy of available GH-stimulation tests, safety of recombinant human GH (rhGH) replacement, unapproved uses of rhGH related to sports and aging, and new developments such as long-acting GH preparations that use a variety of technologies to prolong GH action. Recommendations offer a framework for physicians to manage patients with GHD effectively during transition to adult care and adulthood. Establishing a correct diagnosis is essential before consideration of replacement therapy with rhGH. Since the diagnosis of GHD in adults can be challenging, GH-stimulation tests are recommended based on individual patient circumstances and use of appropriate GH cut-points. Available GH-stimulation tests are discussed regarding variability, accuracy, reproducibility, safety, and contraindications, among other factors. The regimen for starting and maintaining rhGH treatment now uses individualized dose adjustments, which has improved effectiveness and reduced reported side effects, dependent on age, gender, body mass index, and various other individual characteristics. With careful dosing of rhGH replacement, many features of adult GHD are reversible and side effects of therapy can be minimized. Scientific studies have consistently shown rhGH therapy to be beneficial for adults with GHD, including improvements in body composition and quality of life, and have demonstrated the safety of short- and long-term rhGH replacement. Abbreviations: AACE = American Association of Clinical Endocrinologists; ACE = American College of Endocrinology; AHSG = alpha-2-HS-glycoprotein; AO-GHD = adult-onset growth hormone deficiency; ARG = arginine; BEL = best evidence level; BMD = bone mineral density; BMI = body mass index; CI = confidence interval; CO-GHD = childhood-onset growth hormone deficiency; CPG = clinical practice guideline; CRP = C-reactive protein; DM = diabetes mellitus; DXA = dual-energy X-ray absorptiometry; EL = evidence level; FDA = Food and Drug Administration; FD-GST = fixed-dose glucagon stimulation test; GeNeSIS = Genetics and Neuroendocrinology of Short Stature International Study; GH = growth hormone; GHD = growth hormone deficiency; GHRH = growth hormone-releasing hormone; GST = glucagon stimulation test; HDL = high-density lipoprotein; HypoCCS = Hypopituitary Control and Complications Study; IGF-1 = insulin-like growth factor-1; IGFBP = insulin-like growth factor-binding protein; IGHD = isolated growth hormone deficiency; ITT = insulin tolerance test; KIMS = Kabi International Metabolic Surveillance; LAGH = long-acting growth hormone; LDL = low-density lipoprotein; LIF = leukemia inhibitory factor; MPHD = multiple pituitary hormone deficiencies; MRI = magnetic resonance imaging; P-III-NP = procollagen type-III amino-terminal pro-peptide; PHD = pituitary hormone deficiencies; QoL = quality of life; rhGH = recombinant human growth hormone; ROC = receiver operating characteristic; RR = relative risk; SAH = subarachnoid hemorrhage; SDS = standard deviation score; SIR = standardized incidence ratio; SN = secondary neoplasms; T3 = triiodothyronine; TBI = traumatic brain injury; VDBP = vitamin D-binding protein; WADA = World Anti-Doping Agency; WB-GST = weight-based glucagon stimulation test.

DIAGNOSIS OF ENDOCRINE DISEASE: Evaluation of bone fragility in endocrine disorders

An underlying disease affecting bone health is present in up to 40% and 60% of osteoporotic post-menopausal women and men respectively. Among the disorders leading to a secondary form of osteoporosis, the endocrine diseases are highly represented. A frequent finding in patients affected with an endocrine-related forms of bone disease is that the skeletal fragility is partially independent of the bone density, since the fracture risk in these patients is related more to a reduction of bone quality than to a decrease of bone mass. As a consequence, bone mineral density evaluation by dual-X-ray Absorptiometry may be inadequate for establishing the risk of fracture in the setting of the endocrine-related forms of osteoporosis. In the recent years several attempts to non-invasively estimating bone quality have been done. Nowadys, some new tools are available in the clinical practice for optimizing the fracture risk estimation in patients with endocrine disorders. The aim of this review is to summarise the evidences regarding the role of the different imaging tools for evaluating bone density and bone quality in the most frequent forms of endocrine-related osteoporosis, such as obesity, diabetes, acromegaly, thyrotoxicosis, primary hyperparathyroidism, hypercortisolism and hypogonadism. For each of these disorders, data regarding both the current available tools and the future possible new techniques for assessing bone fragility in patients with endocrine diseases are reported.

Systemic Complications of Acromegaly and the Impact of the Current Treatment Landscape: An Update

Acromegaly is a chronic systemic disease with many complications and is associated with increased mortality when not adequately treated. Substantial advances in acromegaly treatment, as well as in the treatment of many of its complications, mainly diabetes mellitus, heart failure, and arterial hypertension, were achieved in the last decades. These developments allowed change in both prevalence and severity of some acromegaly complications and furthermore resulted in a reduction of mortality. Currently, mortality seems to be similar to the general population in adequately treated patients with acromegaly. In this review, we update the knowledge in complications of acromegaly and detail the effects of different acromegaly treatment options on these complications. Incidence of mortality, its correlation with GH (cumulative exposure vs last value), and IGF-I levels and the shift in the main cause of mortality in patients with acromegaly are also addressed.

Bone microarchitecture and volumetric bone density impairment in young male adults with childhood-onset growth hormone deficiency

Context Adult growth hormone deficiency (AGHD) is characterized by low bone density and increased risk of fracture. Bone microarchitecture is insufficiently evaluated in patients with childhood-onset AGHD (CO AGHD). Objective To assess volumetric bone density (vBMD) and bone microarchitecture in CO AGHD in early adulthood after cessation of recombinant growth hormone (rhGH) treatment. Design and subjects Case-control study in a major academic medical center in Beijing, including 20 young male adults with CO AGHD and 30 age- and weight-matched non-athletic healthy men. High-resolution peripheral quantitative computerized tomography (HR-pQCT) of distal radius and tibia was performed. Outcomes The main outcomes were vBMD and morphometry parameters from HR-pQCT. Results Compared with healthy controls, CO AGHD group had significantly decreased insulin-like growth factor 1 (IGF-1) level and IGF-1 SDS (P < 0.001). β-CTX and alkaline phosphatase levels in CO AGHD group were significantly increased (P < 0.001). CO AGHD group had significantly decreased total vBMD, cortical vBMD, trabecular vBMD, cortical area, cortical thickness as well as trabecular thickness and trabecular bone volume fraction of both tibia and radius (P < 0.001). CO AGHD patients had an 8.4 kg decrease in grip strength and a significant decrease in creatinine levels (P = 0.001). At both tibia and radius, by finite element analysis, bone stiffness and failure load of the CO AGHD patients were significantly decreased (P < 0.001). After adjusting for age, BMI and serum levels of testosterone and free thyroxin, serum IGF-1 level was a positive predictor for total vBMD, cortical vBMD, cortical area, trabecular vBMD, bone stiffness and failure load of both tibia and distal radius in all subjects. Conclusions Young adult male patients with childhood-onset adult growth hormone deficiency who are no longer receiving growth hormone replacement have prominently impaired volumetric bone density and bone microarchitecture and lower estimated bone strength.

Insulin Resistance in Patients With Acromegaly

Acromegaly is characterized by chronic overproduction of growth hormone (GH) that leads to insulin resistance, glucose intolerance and, ultimately, diabetes. The GH-induced sustained stimulation of lipolysis plays a major role not only in the development of insulin resistance and prediabetes/diabetes, but also in the reduction of lipid accumulation, making acromegaly a unique case of severe insulin resistance in the presence of reduced body fat. In the present review, we elucidate the effects of GH hypersecretion on metabolic organs, describing the pathophysiology of impaired glucose tolerance in acromegaly, as well as the impact of acromegaly-specific therapies on glucose metabolism. In addition, we highlight the role of insulin resistance in the development of acromegaly-associated complications such as hypertension, cardiac disease, sleep apnea, polycystic ovaries, bone disease, and cancer. Taken together, insulin resistance is an important metabolic hallmark of acromegaly, which is strongly related to disease activity, the development of comorbidities, and might even impact the response to drugs used in the treatment of acromegaly.

A Consensus Statement on acromegaly therapeutic outcomes

The 11th Acromegaly Consensus Conference in April 2017 was convened to update recommendations on therapeutic outcomes for patients with acromegaly. Consensus guidelines on the medical management of acromegaly were last published in 2014; since then, new pharmacological agents have been developed and new approaches to treatment sequencing have been considered. Thirty-seven experts in the management of patients with acromegaly reviewed the current literature and assessed changes in drug approvals, clinical practice standards and clinical opinion. They considered current treatment outcome goals with a focus on the impact of current and emerging somatostatin receptor ligands, growth hormone receptor antagonists and dopamine agonists on biochemical, clinical, tumour mass and surgical outcomes. The participants discussed factors that would determine pharmacological choices as well as the proposed place of each agent in the guidelines. We present consensus recommendations highlighting how acromegaly management could be optimized in clinical practice.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

Effects of active acromegaly on bone mRNA and microRNA expression patterns

OBJECTIVE

To evaluate the response of bone to chronic long-term growth hormone (GH) and insulin-like growth factor-1 (IGF1) excess by measuring the expression of selected mRNA and microRNA (miR) in bone tissue samples of patients with active acromegaly.

DESIGN

Case-control study.

METHODS

Bone tissue samples were obtained during transsphenoidal adenomectomy from the sphenoid bone (sella turcica) from 14 patients with clinically and biochemically confirmed acromegaly and 10 patients with clinically non-functioning pituitary adenoma (NFPA) matched by sex and age. Expression of genes involved in the regulation of bone remodeling was studied using quantitative polymerase chain reaction (qPCR).

RESULTS

Of the genes involved in osteoblast and osteoclast activity, only alkaline phosphatase (ALP) mRNA was 50% downregulated in patients with acromegaly. GH excess caused increased expression of the Wnt signaling antagonists (DKK1) and agonists (WNT10B) and changes in the levels of miR involved in mesenchymal stem cell commitment to chondrocytes (miR-199a-5p) or adipocytes (miR-27-5p, miR-125b-5p, miR-34a-5p, miR-188-3p) P < 0.05; q < 0.1. Relevant compensatory mechanisms were found through the changes in miR involved in osteoblastogenesis (miR-210-5p, miR-135a-5p, miR-211, miR-23a-3p, miR-204-5p), but the expression of TWIST1 was 50% downregulated and RUNX2 was unchanged.

CONCLUSIONS

Acromegaly had minimal effects on tested mRNAs specific to osteoblast or osteoclast function except for downregulated ALP expression. The expressions of miR known to be involved in mesenchymal stem cell commitment and downregulated TWIST1 expression suggest acromegaly has a negative effect on osteoblastogenesis.