Treatment of acromegaly increases BMD but reduces trabecular bone score: a longitudinal study

Long-term depot specific changes in adipose tissue after treatment of acromegaly

CONTEXT

Patients with active acromegaly present a decreased adipose tissue (AT) mass, and short-term studies show that treatment leads to AT depot-specific gain. However, it remains unclear if the increase is persistent in the long-term perspective and/or is sex-dependent.

DESIGN

To characterize the depot-specific changes of AT after treatment of acromegaly and identify contributing factors.

METHODS

Adipose tissue, including visceral (VAT), subcutaneous (SAT), and total (TAT), and android to gynoid ratio (A/G ratio) were measured by dual energy X-ray absorptiometry at diagnosis (n = 62), and after treatment at short-term (median (IQR) 1.9 (1.5-2.3)) and long-term 5.5 (3.9-9.5) years, and correlated to clinical and biochemical measurements. Growth hormone (GH), insulin-like growth factor 1 (IGF-1), glucose and HbA1c levels, gonadal status, and the presence of diabetes mellitus were recorded. Remission status was assessed at the long-term visit (IGF-1/ULN ≤ 1.3). Differences in the temporal course of AT from baseline to short- and long-term follow-up according to sex, diabetes, gonadal, and remission status were evaluated by mixed model analysis, adjusted for age.

RESULTS

Despite a stable body mass index, VAT and A/G ratio increased at both time points, whereas SAT mainly increased at short-term, plateauing afterwards (P < .05 for all). Visceral adipose tissue and A/G ratio were higher in men (P = .035 and P < .001), and the A/G ratio increased more than in women (P = .003). Glucose and HbA1c decreased short-term (P < .05) and remained stable at long-term. The increase in AT depots correlated with the decrease of disease activity at long-term. Remission status had no effect on changes in AT mass during follow-up.

CONCLUSION

Treatment of acromegaly leads to an increase in AT mass in a depot- and sex-specific manner both at short-term and long-term follow-up. Glucose metabolism improves rapidly after disease control and persists.

Trabecular Bone Score Improves Early After Successful Kidney Transplantation Irrespective of Antiresorptive Therapy and Changes in Bone Mineral Density

Background

Trabecular bone score (TBS) is a new tool to assess trabecular bone microarchitecture based on standard dual-energy x-ray absorptiometry (DXA) of lumbar spine images. TBS may be important to assess bone quality and fracture susceptibility in kidney transplant recipients (KTRs). This study aimed to investigate the effect of different bone therapies on TBS in KTRs.

Methods

We reanalyzed DXA scans to assess TBS in 121 de novo KTRs at baseline, 10 wk, and 1 y. This cohort, between 2007 and 2009, participated in a randomized, placebo-controlled trial evaluating the effect of ibandronate versus placebo in addition to vitamin D and calcium.

Results

Although bone mineral density (BMD) Z scores showed a subtle decrease in the first weeks, TBS Z scores increased from baseline to 10 wk for both treatment groups, followed by a slight decline at 12 mo. When comparing treatment groups and adjusting for baseline TBS, there were no differences found in TBS at 12 mo (P = 0.419). Correlation between TBS and BMD at baseline was weak (Spearman's ρ = 0.234, P = 0.010), and change in TBS was not correlated with changes in lumbar spine BMD in either of the groups (ρ = 0.003, P = 0.973).

Conclusions

Treatment with ibandronate or vitamin D and calcium did not affect bone quality as measured by TBS in de novo KTRs, but TBS increased early, irrespective of intervention. Changes in TBS and BMD during the study period were not correlated, indicating that these measurements reflect different aspects of bone integrity. TBS may complement BMD assessment in identifying KTRs with a high fracture risk.

Osteosarcopenia in acromegaly: reduced muscle quality and increased vertebral fat deposition

PURPOSE

Musculoskeletal disorders are among the most disabling comorbidities in patients with acromegaly. This study examined muscle and bone quality in patients with acromegaly.

METHODS

Thirty-three patients with acromegaly and nineteen age- and body mass index-matched healthy controls were included in the study. Body composition was determined using dual-energy X-ray absorptiometry. The participants underwent abdominal magnetic resonance imaging (MRI) for cross-sectional evaluation of muscle area and vertebral MRI proton density fat fraction (MRI-PDFF). Muscular strength was measured using hand grip strength (HGS). Skeletal muscle quality (SMQ) was classified as weak, low, or normal, according to HGS/ASM (appendicular skeletal muscle mass) ratio.

RESULTS

Groups had similar lean tissues, total body fat ratios, and total abdominal muscle areas. Acromegalic patients had lower pelvic BMD (p = 0.012) and higher vertebral MRI-PDFF (p = 0.014), while total and spine bone mineral densities (BMD) were similar between the groups. The SMQ score rate was normal only 57.5% in the acromegaly group, and 94.7% of the controls had a normal SMQ score (p = 0.01). Subgroup analysis showed that patients with active acromegaly (AA) had higher lean tissue and lower body fat ratios than controlled acromegaly (CA) and control groups. Vertebral MRI-PDFF was higher in the CA group than that in the AA and control groups (p = 0.022 and p = 0.001, respectively). The proportion of participants with normal SMQ was lower in the AA and CA groups than that in the control group (p = 0.012 and p = 0.013, respectively).

CONCLUSION

Acromegalic patients had reduced SMQ and pelvic BMD, but greater vertebral MRI-PDFF. Although lean tissue increases in AA, this does not affect SMQ. Therefore, increased vertebral MRI-PDFF in controlled acromegalic patients may be due to ectopic adiposity.

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.

Endocortical Trabecularization in Acromegaly: The Cause for the Paradoxically Increased Vertebral Fracture Risk?

Growth hormone (GH) is nonphysiologically increased in acromegaly, stimulating target tissues directly and indirectly via insulin-like growth factor type 1 (IGF-1). Despite GH having anabolic effects on bone growth and renewal, the risk of vertebral fractures is paradoxically increased in acromegaly. We hypothesized that bone tissue compartments were differentially affected by hormonal alterations in active and controlled acromegaly. We aimed to study the effect of sex and gonadal status on long-term outcome of bone mass and structure to understand the biomechanical competence of bone. We followed 62 patients with newly diagnosed acromegaly longitudinally (median 4.8 years after pituitary surgery) to investigate changes assessed by dual X-ray absorptiometry (DXA), trabecular bone score (TBS), and hip structure analysis (HSA). At diagnosis, patients had increased bone mineral density (BMD) in most compartments compared with normative data (Z-scores). Conversely, TBS Z-score was decreased (Z = -0.64 (SD 1.73), p = 0.028). Following treatment of acromegaly, BMD increased further in compartments containing predominantly trabecular bone, such as the lumbar spine, in eugonadal and male subjects, while compartments with predominantly cortical bone, such as the hip and femoral neck, were unchanged. Total body measurements showed further increase in BMD independent of sex and gonadal status. TBS did not change. HSA revealed a significant decrease in cortical thickness in both sexes independent of gonadal status, whereas the overall size of bone (hip axis length and neck width) did not change over time. In conclusion, patients with acromegaly had increased bone mass and dimensions by DXA. Following normalization of disease activity, BMD increased mainly in compartments rich in trabecular bone, reflecting a closure of the remodeling space. However, HSA revealed a significant decrease in cortical thickness, implying endocortical trabecularization, potentially explaining the increased risk for incident vertebral fractures following treatment. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Update on the clinical use of trabecular bone score (TBS) in the management of osteoporosis: results of an expert group meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO), and the International Osteoporosis Foundation (IOF) under the auspices of WHO Collaborating Center for Epidemiology of Musculoskeletal Health and Aging

PURPOSE

Trabecular bone score (TBS) is a grey-level textural measurement acquired from dual-energy X-ray absorptiometry lumbar spine images and is a validated index of bone microarchitecture. In 2015, a Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) published a review of the TBS literature, concluding that TBS predicts hip and major osteoporotic fracture, at least partly independent of bone mineral density (BMD) and clinical risk factors. It was also concluded that TBS is potentially amenable to change as a result of pharmacological therapy. Further evidence on the utility of TBS has since accumulated in both primary and secondary osteoporosis, and the introduction of FRAX and BMD T-score adjustment for TBS has accelerated adoption. This position paper therefore presents a review of the updated scientific literature and provides expert consensus statements and corresponding operational guidelines for the use of TBS.

METHODS

An Expert Working Group was convened by the ESCEO and a systematic review of the evidence undertaken, with defined search strategies for four key topics with respect to the potential use of TBS: (1) fracture prediction in men and women; (2) initiating and monitoring treatment in postmenopausal osteoporosis; (3) fracture prediction in secondary osteoporosis; and (4) treatment monitoring in secondary osteoporosis. Statements to guide the clinical use of TBS were derived from the review and graded by consensus using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

A total of 96 articles were reviewed and included data on the use of TBS for fracture prediction in men and women, from over 20 countries. The updated evidence shows that TBS enhances fracture risk prediction in both primary and secondary osteoporosis, and can, when taken with BMD and clinical risk factors, inform treatment initiation and the choice of antiosteoporosis treatment. Evidence also indicates that TBS provides useful adjunctive information in monitoring treatment with long-term denosumab and anabolic agents. All expert consensus statements were voted as strongly recommended.

CONCLUSION

The addition of TBS assessment to FRAX and/or BMD enhances fracture risk prediction in primary and secondary osteoporosis, adding useful information for treatment decision-making and monitoring. The expert consensus statements provided in this paper can be used to guide the integration of TBS in clinical practice for the assessment and management of osteoporosis. An example of an operational approach is provided in the appendix. This position paper presents an up-to-date review of the evidence base, synthesised through expert consensus statements, which informs the implementation of Trabecular Bone Score in clinical practice.

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.

Age, body composition parameters and glycaemic control contribute to trabecular bone score deterioration in acromegaly more than disease activity

Introduction

Impairment of bone structure in patients with acromegaly (AP) varies independently of bone mineral density (BMD). Body composition parameters, which are altered in patients with acromegaly, are important determinants of bone strength.

Purpose

The aim of this study was to examine BMD and lumbar trabecular bone score (TBS) by dual-energy X-ray absorptiometry (DXA) and to assess its relationship with disease activity, age, glucose metabolism, and body composition parameters.

Methods

This cross-sectional prospective study involved 115 patients with acromegaly (70 F, 45 M) and 78 healthy controls (CON) (53 F, 25 M) matched for age, gender, and BMI. Bone mineral density, TBS and body composition parameters were measured using DXA.

Results

AP presented with lower TBS compared to CON (1.2 ± 0.1 v 1.31 ± 0.1, P< 0.001). No significant correlation was observed between IGF-1/GH levels and TBS. Age, glycated haemoglobin, BMI, waist circumference, fat mass, and lean mass negatively correlated with TBS in both sexes. Multiple linear regression analysis of all these parameters revealed age and waist circumference as independent significant predictors of TBS in AP. We did not find difference in BMD (lumbar and femoral sites) between AP and CON nor between active and controlled AP. We observed negative correlation between age and BMD of the femoral neck and total hip (P < 0.001). Testosterone levels in males, BMI, waist circumference, fat mass, and lean mass positively correlated with BMD in AP, with stronger correlation between lean mass and BMD compared to fat mass.

Conclusion

Patients with acromegaly have lower TBS than controls, confirming impaired bone microarchitecture in acromegaly regardless of BMD. Age, body composition parameters and glucose metabolism contribute to TBS deterioration in AP more than disease activity itself.

Looking at the spine in controlled Acromegaly

Skeletal fragility with high risk of vertebral fractures (VFs) is an emerging complication of growth hormone (GH) hypersecretion. VFs often coexist with spine arthropathy and both clinical conditions negatively impact on quality of life of acromegalic subjects. Management of spine osteopathy and arthropathy in acromegaly could be challenging since both complications can persist or even progress after biochemical control of disease. This article analyzes the latest evidence about possible pathophysiological links between VFs and spine arthropathy in active and controlled acromegaly, as well as the diagnostic and therapeutic aspects concerning the holistic management of acromegalic osteo-arthropathy.

Trabecular Bone Score as a Reliable Measure of Lumbar Spine Bone Microarchitecture in Acromegalic Patients

Although GH and IGF-1 excess has a controversial impact on bone mineral density (BMD), acromegalic patients display variable degrees of bone structure impairment. In this study, we aim to investigate the usefulness of trabecular bone score (TBS), compared to BMD, in identifying acromegalic patients with impaired lumbar spine trabecular microarchitecture. Forty-four acromegalic patients were investigated for disease control, metabolic and gonadal status, bone metabolism parameters, and the presence of vertebral fractures (VFs). Patients and matched healthy controls underwent BMD and TBS examination. Mean TBS values were lower in patients than in controls (p < 0.001), without significant differences in mean lumbar and femoral BMD. TBS values were significantly higher in controlled patients compared to the uncontrolled ones (p = 0.012). No significant differences were found in bone markers with respect to disease control. Mean TBS or lumbar BMD did not significantly differ in patients with or without VFs (prevalence 11.4%). TBS and BMD levels were lower in hypogonadal patients compared to the eugonadal ones (p = 0.030 and p < 0.001, respectively). In conclusion, TBS values are significantly lower in patients than in controls, confirming the presence of impaired lumbar spine trabecular bone in acromegaly. Both uncontrolled disease and hypogonadism contribute to TBS deterioration in acromegaly.

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 Osteoprotegerin as Useful Tools in the Assessment of Bone Deterioration in Acromegaly

PURPOSE

This study aimed to assess bone mineral density (BMD) and trabecular bone score (TBS) in 61 patients from the acromegaly group (AG) with regard to the activity of the disease in comparison to 42 patients-control group (CG). We also analyzed selected bone markers and their association with BMD and TBS.

MATERIALS AND METHODS

Lumbar spine and femoral neck BMD measurements were performed. TBS values were obtained. Serum concentrations of selected bone markers, including osteoprotegerin (OPG), were measured.

RESULTS

We revealed a difference in TBS values between the AG and CG as well as between the TCA (treatment-controlled acromegaly) vs. CG and TCA+CA (cured acromegaly) vs. CG. We did not observe any statistically significant difference in BMD. OPG had a lower concentration in the CG compared to the AG. TBS correlated negatively with OPG in the AG (r = -0.31, p = 0.01) and in the TCA+ CA group (r = -0.3, p = 0.01).

CONCLUSIONS

The acromegalic patients have altered bone microstructure as indicated by the decreased TBS regardless of the activity of the disease and BMD. OPG could be a marker of the destruction of the bone microstructure, but further studies are needed.

Vertebral Fractures Occur Despite Control of Acromegaly and Are Predicted by Cortical Volumetric Bone Mineral Density

CONTEXT

Recent studies suggest that cortical bone could also play a role in vertebral fracture (VF) development in acromegaly.

OBJECTIVE

Evaluate the occurrence of VFs and their relationship to dual energy x-ray absorptiometry-derived bone parameters.

METHODS

A single-center 2-year prospective study of acromegaly patients was conducted. Each subject had L1-4 spine, femoral neck and total hip (TH) areal BMD measured using DXA, and trabecular bone score (TBS) measurement performed. 3D Shaper™ was used to assess proximal femur trabecular and cortical volumetric (v)BMD, cortical surface (s)BMD, and cortical thickness (Cth). VF assessment was performed using the lateral spine imaging IVA™ mode with a Hologic Horizon® densitometer using a semiquantitative approach. Study outcomes were assessed at 2 time points: baseline and month 24.

RESULTS

70 acromegaly patients (34 M/36F; average 55.1 years) were studied, including 26 with active disease. In 13 patients, 9 with controlled disease, VF was observed. A decrease in TBS, sBMD, neck trabecular vBMD, TH, and neck cortical vBMD in VF compared with non-VF subjects was observed (P < .05). Multivariate analysis of fracture prediction showed TH cortical vBMD as the best fracture prediction parameter with area under the curve of 0.774. TBS was negatively associated with fasting plasma glucose and glycated hemoglobin (HBA1c) at each time point during the follow-up.

CONCLUSION

From the total number of 13 VF subjects, 9 were in the controlled disease group. The most sensitive and specific predictor of incident VF was TH cortical vBMD, suggesting that cortical bone is involved in fracture development.

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.

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.

Application of the Trabecular Bone Score in Clinical Practice

The trabecular bone score (TBS) was introduced as an indirect index of trabecular microarchitecture, complementary to bone mineral density (BMD), and is derived using the same dual energy X-ray absorptiometry images. Recently, it has been approved for clinical use in Korea. Therefore, we conducted a comprehensive review to optimize the use of TBS in clinical practice. The TBS is an independent predictor of osteoporotic fractures in postmenopausal women and men aged >50 years. The TBS is potentially useful in monitoring the skeletal effects of anabolic agents but not of antiresorptive agents. In postmenopausal women with type 2 diabetes mellitus, the TBS assesses osteoporotic fracture risk not captured by BMD. However, high body mass index and soft tissue thickness can cause underestimation of the TBS; however, this limitation has been improved in recent versions of the TBS software. However, a high precision error and low reproducibility limit the use of TBS. This review may provide information on the application of the TBS in clinical practice based on reliable evidence.

Effect of high-intensity training on bone health and body composition in lung transplant recipients: A secondary analysis of a randomized controlled trial

BACKGROUND

Loss of bone mineral and skeletal muscle mass is common after lung transplantation (LTx), and physical activity (PA) may prevent further deterioration. We aimed to assess the effects of 20-week high-intensity training (HIT) on body composition, bone health, and PA in LTx recipients, 6-60 months after surgery.

METHODS

In a randomized controlled trial, 51 LTx recipients underwent Dual-energy X-ray absorptiometry (DXA), and PA level and sedentary time were objectively recorded by accelerometers for seven consecutive days. Of these, 39 participants completed the study, including 19 participants in the HIT group and 20 participants in the standard care group.

RESULTS

Following the intervention, ANCOVA models revealed a nonsignificant between-group difference for change in lean body mass (LBM) and bone mineral density (BMD) of the lumbar spine of 0.4% (95% CI = -3.2, 1.5) (p = .464) and 1.0% (95% CI=-1.3, 3.4) (p = .373), respectively. Trabecular bone score (TBS) of the lumbar spine (L1-L4), however, increased by 2.2 ± 5.0% in the exercise group and decreased by -1.6 ± 5.9% in the control group, giving a between-group difference of 3.8% (95% CI=0.1, 7.5) (p = .043). There were no between-group differences in PA or sedentary time.

CONCLUSION

High-intensity training after LTx improved TBS significantly, but not PA, LBM or BMD.

Spine Bone Texture Assessed by Trabecular Bone Score in Active and Controlled Acromegaly: A Prospective Study

Context

Acromegalic patients have an increased vertebral fracture (VFx) risk due to bone quality reduction, independently of bone mineral density (BMD).

Objective

The aim of the study is to describe bone quality in acromegaly, measured by trabecular bone score (TBS), a noninvasive index for assessing bone microarchitecture.

Methods

We collected data from 18 patients (13 female, age 56.2 ± 15 years) newly diagnosed with acromegaly. Thirty-six age- and sex-matched healthy controls were also recruited. Pituitary function, bone and calcium-phosphorous metabolism, and BMD at spine and femur and TBS (by dual-energy x-ray absorptiometry) were assessed in acromegalic patients at diagnosis and 12 months after the achievement of insulin-like growth factor 1 (IGF-1) normalization.

Results

At diagnosis, BMD and the VFx prevalence were comparable between patients and controls (28.3 ± 5.9 vs 27.6 ± 3.7 and 11% vs 8.3%), whereas TBS was significantly lower in acromegalic patients (1.20 ± 0.13 vs 1.30 ± 0.06; P < .001) and carboxyterminal telopeptide (CTX) and osteocalcin were significantly higher compared to controls (707 ± 365.7 vs 371 ± 104.1 pg/mL; P = .001 and 31.6 ± 15.4 vs 17.0 ± 5.7 ng/mL; P = .001, respectively). One year after IGF-1 normalization, a significant reduction of bone turnover indexes was observed in the group of acromegalic patients surgically cured (osteocalcin decrease of 61.2%, CTX decrease of 60.3%) compared to the ones controlled by medical therapy (osteocalcin decrease of 39%, CTX decrease of 40.7%; P = .01 and P = .001, respectively). Despite these findings, no TBS or BMD variations were observed.

Conclusion

Acromegalic patients have impaired bone quality despite normal density. Achieving normal growth hormone secretion rapidly leads to the normalization of bone turnover.

The Negative Impacts of Acromegaly on Bone Microstructure Not Fully Reversible

PURPOSE

This study aimed to evaluate the bone turnover markers and bone microarchitecture parameters derived from high-resolution peripheral quantitative computed tomography (HR-pQCT) in active and controlled acromegaly patients.

METHODS

This cross-sectional study involved 55 acromegaly patients from a tertiary hospital (23 males and 32 females, aged 45.0 ± 11.6 years). Firstly, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and markers for bone turnover were assessed. Next, we derived peripheral bone microstructure parameters and volumetric bone mineral density (vBMD) through HR-pQCT. These parameters were compared between acromegaly patients and 110 healthy controls, as well as between 27 active and 28 controlled acromegaly patients. Moreover, the relationship between GH/IGF-1 and bone microstructure parameters was analyzed through multiple linear regression.

RESULTS

As compared with healthy controls, acromegaly patients exhibited elevated cortical vBMD, reduced trabecular vBMD, and increased trabecular inhomogeneity in the distal radius and tibia. While controlled acromegaly patients had slower bone turnover, they did not necessarily have better bone microstructure relative to active patients in intergroup comparison. Nevertheless, multiple regression indicated that higher IGF-1 was associated with lower tibial stiffness and failure load. Additionally, males with higher IGF-1 typically had larger trabecular separation, lower trabecular number, and larger cortical pores in the radius. Moreover, patients with elevated GH typically had more porous cortical bone in the radius and fewer trabeculae in the tibia. However, the compromised bone strength in active patients was partially compensated by increased bone thickness. Furthermore, no significant linkage was observed between elevated GH/IGF-1 and the most important HR-pQCT parameters such as trabecular volumetric bone density.

CONCLUSION

Acromegaly adversely affected bone quality, even in controlled patients. As the deterioration in bone microstructure due to prolonged GH/IGF-1 exposure was not fully reversible, clinicians should be aware of the bone fragility of acromegaly patients even after they had achieved biochemical remission.

Biochemical bone turnover markers in hormonal disorders in adults: a narrative review

BACKGROUND

Hormonal disorders are often associated with abnormal levels of bone turnover markers (BTMs). N-terminal propeptide of type I procollagen (PINP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) are the reference markers of bone formation and bone resorption, respectively.

METHODS

A comprehensive literature search within the MEDLINE and Web of Science databases was performed.

RESULTS

Acromegaly is associated with higher BTM levels, which decrease during the remission after treatment. Adult-onset growth hormone deficiency is often associated with decreased BTM levels. Growth hormone replacement therapy stimulates bone turnover and increases BTM levels. Hypothyroidism is characterized by general slowing of bone metabolism which is reflected by lower BTM levels. The replacement thyroid hormone therapy increases the bone turnover rate and BTM levels increase. Patients with thyroid cancer receive a suppressive dose of thyroid hormones and may have slightly elevated BTM levels. Patients with overt hyperthyroidism had higher BTM levels and anti-thyroid therapy induces a rapid decrease in the BTM levels. Patients with overt primary hyperparathyroidism have higher BTM levels, whereas those with asymptomatic and normocalcemic hyperparathyroidism usually have normal BTM levels. Hypoparathyroidism is characterized by slightly decreased BTM levels. Cushing's syndrome is characterized consistently by markedly decreased osteocalcin concentration, whereas data on other BTMs are discordant.

CONCLUSIONS

BTMs help us to better understand mechanisms of the impact of hormonal disorders and their treatment on bone metabolism. However, it is unknown whether BTMs may be used to monitor the effect of their treatments on bone in the clinical practice.

Treatment of Acromegalic Osteopathy in Real-life Clinical Practice: The BAAC (Bone Active Drugs in Acromegaly) Study

BACKGROUND

Vertebral fractures (VFs) are a frequent complication of acromegaly, but no studies have been so far published on effectiveness of antiosteoporotic drugs in this clinical setting.

OBJECTIVE

To evaluate whether in real-life clinical practice bone active drugs may reduce the risk of VFs in patients with active or controlled acromegaly.

STUDY DESIGN

Retrospective, longitudinal study including 9 tertiary care endocrine units.

PATIENTS AND METHODS

Two hundred and forty-eight patients with acromegaly (104 males; mean age 56.00 ± 13.60 years) were evaluated for prevalent and incident VFs by quantitative morphometric approach. Bone active agents were used in 52 patients (20.97%) and the median period of follow-up was 48 months (range 12-132).

RESULTS

During the follow-up, 65 patients (26.21%) developed incident VFs in relationship with pre-existing VFs (odds ratio [OR] 3.75; P < .001), duration of active acromegaly (OR 1.01; P = .04), active acromegaly at the study entry (OR 2.48; P = .007), and treated hypoadrenalism (OR 2.50; P = .005). In the entire population, treatment with bone active drugs did not have a significant effect on incident VFs (P = .82). However, in a sensitive analysis restricted to patients with active acromegaly at study entry (111 cases), treatment with bone active drugs was associated with a lower risk of incident VFs (OR 0.11; P = .004), independently of prevalent VFs (OR 7.65; P < .001) and treated hypoadrenalism (OR 3.86; P = .007).

CONCLUSIONS

Bone active drugs may prevent VFs in patients with active acromegaly.

TSH suppressive therapy and bone

Thyroid hormones stimulate bone turnover in adults by increasing osteoclastic bone resorption. TSH suppressive therapy is usually applied in patients with differentiated thyroid cancer (DTC) to improve the disease outcome. Over the last decades several authors have closely monitored the potential harm suffered by the skeletal system. Several studies and meta-analyses have shown that chronic TSH suppressive therapy is safe in premenopausal women and men. Conversely, in postmenopausal women TSH suppressive therapy is associated with a decrease of bone mineral density, deterioration of bone architecture (quantitative CT, QCT; trabecular bone score, TBS), and, possibly, an increased risk of fractures. The TSH receptor is expressed in bone cells and the results of experimental studies in TSH receptor knockout mice and humans on whether low TSH levels, as opposed to solely high thyroid hormone levels, might contribute to bone loss in endogenous or exogenous thyrotoxicosis remain controversial. Recent guidelines on the use of TSH suppressive therapy in patients with DTC give value not only to its benefit on the outcome of the disease, but also to the risks associated with exogenous thyrotoxicosis, namely menopause, osteopenia or osteoporosis, age >60 years, and history of atrial fibrillation. Bone health (BMD and/or preferably TBS) should be evaluated in postmenopausal women under chronic TSH suppressive therapy or in those patients planning to be treated for several years. Antiresorptive therapy could also be considered in selected cases (increased risk of fracture or significant decline of BMD/TBS during therapy) to prevent bone loss.

Increased Serum Sclerostin Levels in Patients With Active Acromegaly

CONTEXT

Bone mineral density is normal in acromegalic patients and the cause of increased fracture risk that characterizes active acromegaly is unknown.

OBJECTIVE

This study compared serum sclerostin levels between patients with active acromegaly and healthy individuals.

DESIGN, SETTING, AND PARTICIPANTS

The serum sclerostin levels of patients with active acromegaly were compared with those of healthy volunteers in a cross-sectional study. The mean age of the 30 acromegaly patients (male/female: 14/16) was 47.26 ± 12.52 years (range, 18-64 years) and that of the healthy volunteers (male/female: 17/13) was 44.56 ± 10.74 years (range, 19-62 years). IGF-1 and GH levels were measured using an electrochemiluminescence method, and serum sclerostin levels using an ELISA. The Mann-Whitney U test was used to compare sclerostin levels between the 2 groups. The correlations of sclerostin level with IGF-1 and GH were determined using Spearman's test.

RESULTS

The 2 groups did not differ in age or sex (P > 0.05). The median GH and IGF-1 levels in the patient group were 2.49 ng/mL (range, 0.22-70.00 ng/mL) (interquartile range [IQR], 1.3-4.52) and 338.5 ng/mL (range, 147-911 ng/mL) (IQR, 250-426), respectively. The median GH and IGF-1 levels in the control group were 0.95 ng/mL (range, 0.3-2.3) and 144 ng/mL (range, 98-198), respectively. The median sclerostin level was 29.95 ng/mL (range, 7.5-78.1 ng/mL) (IQR, 14.37-37.47) in the acromegaly group and 22.44 ng/mL (range, 8.45-36.44 ng/mL) (IQR, 13.71-27.52) in the control group (P < 0.05). There was a moderate positive correlation between the sclerostin and IGF-1 levels (rho = 0.54; P < 0.01), and between the sclerostin and GH levels (rho = 0.41; P < 0.05).

CONCLUSIONS

High sclerostin levels may contribute to the increased fracture risk seen in patients with acromegaly.

Effects of Pegvisomant and Pasireotide LAR on Vertebral Fractures in Acromegaly Resistant to First-generation SRLs

PURPOSE

Osteopathy is an emerging complication of acromegaly. In somatostatin receptor ligands (SRL)-resistant patients, pegvisomant (PegV) and pasireotide LAR (Pasi) are used for acromegaly treatment, but their effect on skeletal health is still not defined.

METHODS

In a longitudinal retrospective international study, we evaluated incidence of radiological vertebral fractures (VFs) in 55 patients with acromegaly resistant to first-generation SRL.

RESULTS

At study entry, prevalent VFs occurred in 23 patients (41.8%). Biochemical acromegaly control was reached in 66.7% of patients on PegV and in 66.7% of patients on Pasi. During the follow-up, incident VFs (iVFs) were detected in 16 patients (29.1%). Occurrence of iVFs was associated with prevalent VFs (P = .002), persistence of active acromegaly (P = .01) and higher value of insulin-like growth factor 1 (IGF-1) during follow-up (P = .03). Among patients with active disease at last visit, iVFs occurred less frequently in patients on treatment with Pasi (25%) compared to PegV (77.8% P = .04), independently of the IGF-1 values (P = .90). In patients who reached biochemical control, 22.7% on PegV and 12.5% on Pasi had iVFs (P = .40). Among both treatment groups, the presence of pre-existent VFs was the main determinant for iVFs.

CONCLUSION

Our data show for the first time that patients with biochemically active disease treated with Pasi had lower risk of iVFs versus those treated with PegV. It also confirms that the presence of pre-existent VFs was the main determinant for iVFs. Additional studies on larger populations and with longer follow-up are needed to confirm our data and disclose the mechanisms underlying our findings.

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.

[Not Available]

Acromegaly is characterized by increased release of growth hormone (GH) and, consequently, Insulin-Like Growth Factor I (IGF-I), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Transsphenoidal adenomectomy is the treatment of choice of GH-secreting pituitary tumors but surgical cure is not achieved in around 50% of patients, then adjuvant treatment is necessary. Mortality in acromegaly is normalized with biochemical control and has decreased in the last decade with the increased use of adjuvant therapy. Both GH and IGF-I are currently biomarkers for assessing disease activity in patients with acromegaly. However, discordance between GH and IGF-I results is encountered in a quarter of treated patients. The impacts of such a discrepancy over mortality and morbidity and the risk of biochemical and/or clinical recurrence are unclear. Moreover, despite a good biochemical control, some symptoms persist, leading to a decreased quality of life. Back pain due to vertebral fractures seem to be frequent in these patients and underdiagnosed. In patients with acromegaly, bone mineral density is not a reliable predictor of fracture risk. A more accurate evaluation of bone microstructural alterations associated with GH hypersecretion and vertebral fractures may be provided by new radiological devices analyzing alteration of trabecular microarchitecture, leading to a better prevention. © 2019 Published by Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Les Must de l'Endocrinologie 2019 réalisé avec le soutien institutionnel de Ipsen-Pharma.

Current perspectives on the impact of clinical disease and biochemical control on comorbidities and quality of life in acromegaly

Acromegaly is a rare chronic, systemic disorder caused by excessive growth hormone (GH) secretion from a somatotroph pituitary adenoma. GH hypersecretion leads to overproduction of insulin-like growth factor-1 (IGF-1), which contributes to the somatic overgrowth, physical disfigurement, onset of multiple systemic comorbidities, reduced quality of life (QoL) and premature mortality of uncontrolled patients. Somatostatin receptor ligands, dopamine agonists and a GH receptor antagonist are currently available for medical therapy of acromegaly. The main aim of treatment is biochemical normalisation, defined as age-normalised serum IGF-1 values and random GH levels <1.0 μg/L. However, there is an increasing evidence suggesting that achieving biochemical control does not always decrease the burden of disease-related comorbidities and/or improve patients' QoL. This lack of correlation between biochemical and clinical control can be due to both disease duration (late diagnosis) or to the peculiarity of a given comorbidity. Herein we conducted ad hoc literature searches in order to find the most recent and relevant reports on biochemical and clinical disease control during medical treatment of acromegaly. Particularly, we analyse and describe the relationship between biochemical, as well as clinical disease control in patients with acromegaly receiving medical therapy, with a focus on comorbidities and QoL. In conclusion, we found that current literature data seem to indicate that clinical disease control (besides biochemical control), encompassing clinical signs and symptoms, comorbidities and QoL, emerge as a primary focus of acromegaly patient management.

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.

Circulating miR-103a-3p and miR-660-5p are associated with bone parameters in patients with controlled acromegaly

Background Biochemical control of GH/IGF-I excess in acromegaly (ACRO) is associated with persistent impairment of trabecular microstructure leading to increased risk of vertebral fractures. Circulating miRNAs modulate the activity of osteoblasts and osteoclasts, and may be potential biomarkers of osteoporosis. Aims Identify differentially expressed miRNAs in the serum of patients with controlled ACRO vs controls and correlate miRNA levels with both biochemical and structural bone parameters. Patients and methods Twenty-seven patients with controlled ACRO (11 males, 16 females; mean age, 48 ± 5 years; BMI, 28 ± 4 kg/m2) and 27 age-, gender- and BMI-matched controls were recruited. Areal BMD at lumbar spine and femur, and trabecular bone score were assessed; volumetric BMD was measured by quantitative computed tomography QCT-Pro (Mindways). Twenty miRNAs, chosen by their putative role in bone, were quantified in serum using real-time qPCR. Results In ACRO patients, miR-103a-3p and miR-191-5p were found overexpressed, whereas miR-660-5p was underexpressed (P < 0.001). miR-103a-3p levels were negatively associated with both trabecular vBMD at trochanter and serum osteoprotegerin concentrations (P < 0.05) and positively with vitamin D concentrations (P < 0.01) and total cross-sectional area of the femoral neck (P < 0.05). miR-660-5p levels were correlated with both trabecular vBMD at trochanter and OPG concentrations (P < 0.05), but were negatively associated with vitamin D levels (P < 0.05). A negative correlation between miR-103-a-3p and miR-660-5p was found in both groups (P < 0.001). Conclusions Circulating miR-103a-3p and miR-660-5p are differentially expressed in controlled ACRO patients and associated with bone structural parameters. miRNAs may be one of the mechanisms involved in the pathogenesis of bone disease and could be used as biomarkers in ACRO patients.

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 pegvisomant and somatostatin receptor ligands on incidence of vertebral fractures in patients with acromegaly

PURPOSE

Acromegalic osteopathy is an emerging complication of acromegaly characterized by increase in bone turnover, deterioration in bone microarchitecture and high risk of vertebral fractures (VFs). Somatostatin receptor ligands (SRLs) and pegvisomant (PegV) are used for treatment of acromegaly and there is evidence that both drugs may exert direct effects on peripheral targets regardless of biochemical control of disease. However, whether or not SRLs and PegV may directly influence skeletal health its is unknown.

METHODS

In this longitudinal study, we evaluated the incidence of radiological VFs in 83 patients (48 females, 35 males; median age 47 years, range 18-80 years) who were treated with SRLs alone (42 cases), PegV alone (6 cases) or in combination with SRLs (35 cases) for median period of 82 months (range 36-126). PegV was given when acromegaly was not controlled by SRLs alone.

RESULTS

During the follow-up, 29 patients (34.9%) developed incident VFs. In patients receiving PegV due to active disease during SRL therapy, incidence of VFs decreased significantly from 43.9 to 26.8% (p = 0.039). When acromegaly was controlled by PegV, the incidence of VFs was slightly but not significantly lower as compared to that observed in patients with biochemical control of disease by SRLs (10.0 vs. 26.7%; p = 0.09). In the multivariate logistic regression analysis, incident VFs were independently predicted by pre-existing VFs (odds ratio 61.0; p = 0.009), duration of active acromegaly (odds ratio 1.01; p = 0.05) and mean serum IGF-I during the follow-up (odds ratio 5.26; p = 0.03), regardless of the therapeutic regimen (odds ratio 1.05; p = 0.94).

CONCLUSIONS

PegV and SRLs had comparable effects on VF risk in acromegaly. The activity of disease was the main determinant of VFs independently of the drug used to control acromegaly.

Bone histomorphometry in acromegaly patients with fragility vertebral fractures

CONTEXT

The high risk of vertebral fractures (VFs) in acromegaly patients despite normal bone mineral density (BMD) is well known. The reasons for this paradoxical finding of skeleton fragility are poorly understood due to the limited data on bone histomorphometry in acromegaly.

OBJECTIVE

This study aimed to analyze histomorphometric parameters including bone microarchitecture in acromegaly patients with VFs and normal BMD compared to normal subjects, and also to evaluate the differences between active and controlled acromegaly patients.

PATIENTS AND METHODS

Forty-seven acromegaly patients (17 active, 30 controlled), median (range) age 57 years (30-88) were evaluated for bone turnover, morphometric VFs and BMD by dual-energy X-ray absorptiometry at lumbar spine and hip; 12 patients with VFs and normal BMD underwent iliac crest bone biopsy; 12 biopsies were taken at the autopsy in healthy sex and age-matched control subjects.

RESULTS

The histomorphometric evaluation of acromegaly fractured patients was compared with that of normal controls and showed significantly reduced median (range) levels of bone volume/tissue volume (BV/TV: 15.37% (7.93-26.75) vs. 18.61% (11.75-27.31), p = 0.036), trabecular thickness (TbTh: 77.6 µm (61.7-88.3) vs. 82.7 µm (72.3-92.0) p = 0.045), with increased trabecular separation (TbSp: 536.4 µm (356.2-900.6) vs. 370.3 µm (377.1-546.3) p = 0.038) and increased cortical thickness (1268 μm (752-2521) vs. 1065 μm (851-1205) p = 0.025) and porosity (11.9% (10.2-13.3) vs. 4.8% (1.6-8.8) p = 0.0008). While active acromegaly patients showed histomophometric features of increased bone turnover, patients with controlled disease presented normal bone turnover with significantly lower osteoblastic activity, expressed as osteoblast number (p = 0.001), active osteoblasts and vigor (p = 0.014) in the presence of reduced osteocyte number (p = 0.008) compared to active disease.

CONCLUSIONS

The apparent paradox of bone fragility in acromegaly patients with a normal BMD can be explained by increased cortical thickness and porosity and reduced trabecular thickness with increased trabecular separation. These structural and microarchitectural abnormalities persist in the controlled phase of acromegaly despite bone turnover normalization. The main determinant of bone disease after hormonal control is severe osteoblastic dysfunction.

Prevalence of morphometric vertebral fractures in "difficult" patients with acromegaly with different biochemical outcomes after multimodal treatment

INTRODUCTION

Skeletal fragility with high risk of vertebral fractures is an emerging complication of acromegaly in close relationship with duration of active disease. The aim of this cross-sectional study was to evaluate the prevalence and determinants of vertebral fractures in males and females with a history of long-standing active acromegaly undergoing treatment with Pegvisomant.

SUBJECTS AND METHODS

Thirty-eight patients (25 females, 13 males) with acromegaly under Pegvisomant therapy were evaluated for vertebral fractures and bone mineral density at lumbar spine and femoral neck. Gonadal status, serum IGF1 levels and growth hormone receptor genotype were also assessed.

RESULTS

Vertebral fractures were detected in 12 patients (31.6%). Fractured patients had longer duration of active disease (p = 0.01) with higher frequency of active acromegaly (p = 0.04), received higher dose of Pegvisomant (p = 0.008), and were more frequently hypogonadic (p = 0.02) as compared to patients who did not fracture. Stratifying the patients for gender, vertebral fractures were significantly associated with Pegvisomant dose (p = 0.02) and untreated hypogonadism (p = 0.02) in males and with activity of disease (p = 0.03), serum insulin-like growth factor-I values (p = 0.01) and d3GHR polymorphism (p = 0.005) in females. No significant association was found between vertebral fractures and bone mineral density at either skeletal site.

CONCLUSION

Vertebral fractures are a frequent complication of long-standing active acromegaly. When patients are treated with Pegvisomant, vertebral fractures may occur in close relationship with active acromegaly and coexistent untreated hypogonadism.

Bone material strength index as measured by impact microindentation is altered in patients with acromegaly

OBJECTIVE

Acromegaly is a rare disease caused by excess growth hormone (GH) production by the pituitary adenoma. The skeletal complications of GH and IGF-1 excess include increased bone turnover, increased cortical bone mass and deteriorated microarchitecture of trabecular bone, associated with a high risk of vertebral fractures in the presence of relatively normal bone mineral density (BMD). We aimed to evaluate tissue-level properties of bone using impact microindentation (IMI) in well-controlled patients with acromegaly aged ≥18 years compared to 44 controls from the outpatient clinic of the Centre for Bone Quality.

DESIGN AND METHODS

In this cross-sectional study, bone material strength index (BMSi) was measured in 48 acromegaly patients and 44 controls with impact microindentation using the osteoprobe.

RESULTS

Mean age of acromegaly patients (54% male) was 60.2 years (range 37.9-76.5), and 60.5 years (range 39.8-78.6) in controls (50% male). Patients with acromegaly and control patients had comparable BMI (28.2 kg/m² ± 4.7 vs 26.6 kg/m² ± 4.3, P = 0.087) and comparable BMD at the lumbar spine (1.04 g/cm² ± 0.21 vs 1.03 g/cm² ± 0.13, P = 0.850) and at the femoral neck (0.84 g/cm² ± 0.16 vs 0.80 g/cm² ± 0.09, P = 0.246). BMSi was significantly lower in acromegaly patients than that in controls (79.4 ± 0.7 vs 83.2 ± 0.7; P < 0.001).

CONCLUSION

Our data indicates that tissue-level properties of cortical bone are significantly altered in patients with controlled acromegaly after reversal of long-term exposure to pathologically high GH and IGF-1 levels. Our findings also suggest that methods other than DXA should be considered to evaluate bone fragility in patients with acromegaly.

Acromegalic osteopathy

Acromegalic osteopathy is an emerging complication of acromegaly characterized by increase in bone turnover, deterioration in bone microarchitecture and high risk of vertebral fractures. Vertebral fractures, as diagnosed by a radiological and morphometric approach, occur in about one-third of acromegaly patients in close relationship with duration of active disease. However, the prediction of vertebral fractures in this clinical setting is still a matter of uncertainty, since the pathogenesis of acromegalic osteopathy is multifactorial and fractures may occur even in presence of normal bone mineral density. In this narrative article, we summarize the pathophysiology and clinical aspects of acromegalic osteopathy.

NEWS IN ACROMEGALY

Recent updates on the epidemiology, diagnosis, complications and therapy in acromegaly have been published in the 1^st 2017 issue of Pituitary journal. A review of 12 epidemiological studies published since 2004 shows that the prevalence of acromegaly ranges 2.8 - 13.7 cases per 100,000 people and the annual incidence rates range 0.2 - 1.1 cases/100,000 people. The median age at diagnosis ranges between 40.5 and 47 years. At the time of diagnosis, over 2/3 of the patients have macroadenomas. Acromegalic osteopathy is characterized by increase in bone turnover, alterations in bone microarchitecture and high risk of vertebral fractures, which occur in about 1/3 of acromegaly patients. Fractures may occur even in the presence of normal bone mineral density (BMD), in close relationship with male gender, hypogonadism, and active acromegaly. Following treatment for acromegaly in 48 patients, the mean trabecular bone score decreased by 3.0 (±7.0) %, whereas BMD at the lumbar spine increased by 3.2 (±4.9) % (both P<0.01). Alterations in trabecular bone architecture may explain the persistent fracture risk despite the increase in BMD after disease control. Stereotactic radiotherapy in acromegaly after surgery and/or during medical therapy provide tumor control in 93-100% of patients at 5-10 years and endocrinological remission in 40-60% of patients at 5 years, with a hypopituitarism rate of 10-50% at 5 years. Hypofractionated radiosurgery is an optimal option for tumors located near the optic structures, due to its lower toxicity for the optic nerves compared to single-dose radiosurgery. A dose-response model for visual pathway tolerance to SRS has been recently published.