The risk factors for fractures and trabecular bone-score value in patients with endogenous Cushing's syndrome

Screening for endogenous hypercortisolism in patients with osteoporosis and fractures: why, when and how

Skeletal comorbidities are frequent and clinically relevant findings in Cushing's syndrome (CS) since an uncoupled suppressed bone formation and enhanced bone resorption leads to a marked skeletal damage with a rapid increase of fracture risk. Reduced Bone Mineral Density (BMD) has been consistently reported and osteopenia or osteoporosis are typical findings in patients with CS. Vertebral Fractures (VFs) are frequently reported and may occur even in patients with an only mild reduction of BMD. Since CS is diagnosed late due to often difficult biochemical and radiological confirmation as well as to signs and symptoms common in other much more frequent diseases an approach suggested for overcoming underdiagnosis is to screen patients with manifestations which may overlap with those of CS such as arterial hypertension, diabetes mellitus and osteoporosis. Our review will focus on the rationale and best practice for screening osteoporotic patients for CS.

Multiple pathological bone fractures in a dog with adrenal-dependent Cushing's syndrome

Pathological bone fractures may occur secondarily to Cushing's syndrome in people. Although low bone mineral density due to cortisol excess has been described in dogs, there is no evidence that dogs with Cushing's disease can develop osteoporosis or secondary bone fractures. Here, we report a case of a dog with Cushing's disease and multiple pathological bone fractures. A 14-year-old female spayed mixed-breed dog was attended due to progressive lethargy, weakness, difficulty moving, trembling and clinical signs of Cushing's syndrome (polyuria, polydipsia, alopecia and abdominal distension). After confirmation of the diagnosis of Cushing's disease and 2 days after starting trilostane treatment (0.27 mg/kg every 12 hours), the dog presented to our hospital with reluctance to rise. In the computed tomography scan, decreased bone density in cervical and thoracic vertebrae, ribs scapular bones and multiple rib fractures were detected. Despite 8 days of hospitalisation, reluctance to rise and walk persisted. Given the unfavourable progression of the diseases, the owner opted for euthanasia. Post mortem evaluation confirmed a cortical carcinoma of the left adrenal gland and thin, irregular spicules and trabeculae of compact bone and reduced thickness of the cortex of the ribs.

Hormones synthesized by the adrenal reticulum protect bone density in premenopausal women with Cushing syndrome

BACKGROUND

Differences in bone metabolism between patients with adrenal Cushing's syndrome (ACS) and Cushing's disease (CD) have been noted, but the impact of steroid hormones on bone metabolism remains underexplored. The purpose of this study is to explore the differences in bone metabolism between the two subtypes of Cushing's syndrome and the correlation between hormones synthesized by the adrenal reticulum and bone metabolism.

METHOD

This retrospective study included 75 premenopausal women, consisting of 33 patients with CD and 42 patients with ACS. The clinical characteristics, laboratory examination and bone metabolism differences between the two groups were analyzed. Then, 16 patients with ACS and 12 patients with CD underwent comparison of blood steroid hormone levels. Additionally, the relationship between bone mineral density (BMD) values and steroid hormone variables was analyzed.

RESULTS

The serum and urinary cortisol and serum ACTH concentrations were significantly higher in patients with CD compared to those with ACS. Conversely, lumbar and femoral BMD were lower, and osteocalcin (OC) levels were elevated in the ACS group. Dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulphate (DHEAS) had a significant positive correlation with Z-score in lumbar spine in both CD and ACS group. However, Z-score in femoral neck had a significant positive correlation with DHEA and DHEAS only in the ACS group.

CONCLUSION

Bone loss is more pronounced in ACS than in CD, despite higher cortisol levels in CD patients. High levels of hormones synthesized by the adrenal reticulum might be protective for bone density in premenopausal women with hypercortisolism.

Relationship Among Fragility Fractures and the Overall Cardiovascular Burden in Endogenous Cushing Syndrome

Context

Patients with endogenous Cushing syndrome (CS), in addition to significant cardiovascular morbidity, are burdened by a high prevalence of fragility fractures. Bone mineral density (BMD) alone poorly predicts the risk of fracture, and the implementation of trabecular bone score (TBS) is supported only by scant evidence. Indeed, reliable predictors of fractures in endogenous CS are still lacking.

Objective

This work aimed to analyze the prevalence and the potential predictors of fragility fractures in our patients with CS.

Methods

A monocentric, retrospective, cross-sectional study. A total of 51 patients with overt CS were enrolled. Main outcome measures included biochemical evaluation, BMD measurement, TBS evaluation, fracture presence, body composition evaluation, and arterial intima-media thickness (IMT) assessment.

Results

Fragility fractures were found in 62.7% of patients at diagnosis. Fractured patients exhibited lower spine T-score (P = .03), longer disease duration (P = .025), higher waist circumference (P = .006), and predominantly male sex (P = .008). Increased serum uric acid levels (P = .001), greater IMT (P = .017), and higher prevalence of venous thromboembolism events (31.3% vs 5.3%, P = .037) and atherosclerotic plaques (47% vs 5.3%, P = .002) were described in the fracture group.Multivariable logistic regression identified the presence of atherosclerosis (OR 13.35; 95% CI 1.154-154.34, P = .038) and osteoporosis (OR 11.30; 95% CI 1.55-82.56, P = .017) as independent predictors. TBS values were inversely correlated with body mass index, fat and lean mass, and serum uric acid, and positively correlated with high-density lipoprotein cholesterol.

Conclusion

CS patients with higher overall burden of cardiovascular morbidity are more prone to experience fragility fractures.

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.

Cushing's disease and bone

Bone impairment associated with Cushing's disease (CD) is a complex disorder, mainly involving deterioration of bone quality and resulting in an increased fracture rate, often despite normal bone mineral density. Bone complications are common in patients with CD at the time of diagnosis but may persist even after successful treatment. There is currently no agreement on the optimal diagnostic methods, thresholds for anti-osteoporotic therapy and its timing in CD. In this review, we summarize the current data on the pathophysiology, diagnostic approach and management of bone complications in CD.

High prevalence of morphometric vertebral fractures opportunistically detected on thoracic radiograms in patients with non-functioning pituitary adenoma

PURPOSE

Vertebral fractures (VFs), the hallmark of skeletal fragility, have been reported as an emerging complication in patients with pituitary diseases associated with hormonal excess and/or deficiency, independently from bone mineral density. Non-functioning pituitary adenoma (NFPA) is amongst the most frequent pituitary adenomas; however, skeletal health in this context has never been investigated. We aimed at assessing the prevalence and the determinants of morphometric VFs in patients with NFPA.

METHODS

We enrolled 156 patients (79 M/77F, mean age 55.75 ± 12.94 years) at admission in Neurosurgery Unit before trans-sphenoidal surgery and compared them with an age and sex-matched control group of subjects with neither history/risk factors for secondary osteoporosis nor pituitary disorders. We performed a vertebral morphometric evaluation of the thoracic spine on pre-operative X-ray images (MTRx) and collected biochemical, demographic, and clinical data from the entire cohort.

RESULTS

The prevalence of thoracic VFs in patients with NFPA was significantly higher than the control group (26.3% vs. 10.3%; p < 0.001). In the NFPA group, 20 patients (48.8% of the fractured patients) showed multiple VFs, 14 (34.1% of them) showed moderate/severe VFs. Patients with VFs were significantly older and had lower serum free triiodothyronine (fT3) levels than non-fractured ones (p = 0.002 and p = 0.004; respectively). The prevalence of secondary male hypogonadism was higher among men with VFs as compared to those with no VFs (72% vs. 48.1%; p = 0.047). Consistently, total testosterone levels in males were significantly lower in fractured patients than in non-fractured ones (p = 0.02). The prevalence of gonadotroph adenomas was significantly higher among patients with VFs (p = 0.02). In multiple logistic regression analysis, older age and lower serum fT3 levels were independent factors predicting the risk for VFs.

CONCLUSIONS

For the first time, we reported a high prevalence of thoracic radiological VFs in patients with NFPAs. Our data should prompt clinicians to proceed with a clinical bone fragility evaluation already during the diagnostic work-up, particularly in those with concomitant hypogonadism, or in those with older age and/or with lower fT3.

Trabecular bone score (TBS) in Cushing's disease: TBS gain after hypercortisolism normalization

CONTEXT

Hypercortisolism frequently induces trabecular bone loss, more pronounced at the lumbar spine, resulting in osteoporosis, and thus an increase in fracture risk. Several studies have shown bone mass recovery in patients with Cushing's disease (CD) after treatment.

OBJECTIVE

To examine treatment effects on TBS (trabecular bone score) in addition to aBMD (areal bone mineral density) in a cohort of patients with CD.

DESIGN AND SETTING

Single-center retrospective longitudinal study in patients diagnosed with CD and successfully treated following surgery and/or medical treatment.

PATIENTS

We included 31 patients with median age and BMI (body mass index) of 37.7 [28.4;43.3] years old and 27.7 [25.8;30.4] kg/m2, respectively. Median 24 h urinary cortisol before treatment was 213.4 [168.5;478.5] μg/24 h. All subjects were completely biochemically controlled or cured after treatment.

MAIN OUTCOME MEASURES

aBMD and TBS were evaluated at AP Spine (L1-L4) with DXA prodigy (GE-Lunar), QDR 4500 (Hologic), and TBS iNsight® (Med-Imaps) before and after treatment.

RESULTS

Absolute TBS and aBMD gains following cure of CD were significant (p < 0.0001, and p < 0.001, respectively). aBMD and TBS increased by +3.9 and 8.2 % respectively after cure of CD. aBMD and TBS were not correlated before (p = 0.43) and after treatment (p = 0.53). Linear regression analyses showed that TBS gain was independent of baseline BMI and that low TBS at baseline was predictive of TBS gain after treatment.

CONCLUSION

The more significant improvement of microarchitecture assessed by TBS than aBMD and the absence of correlation between TBS and aBMD suggest that TBS may be an adequate marker of bone restoration after cure of CD. To support this conclusion, future studies with larger sample sizes and longer follow-up periods should be carried out.

Evaluation of Trabecular Bone Microarchitecture and Bone Mineral Density in Young Women, Including Selected Hormonal Parameters

The absence of non-invasive methods for assessing bone material and structural changes is a significant diagnostic challenge. Dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) testing is the gold standard for osteoporosis diagnosis. BMD and the trabecular bone score (TBS) have facilitated targeted osteoporosis prevention and treatment in clinical settings. The findings from this study indicate that BMD modulation in young women is influenced by various hormones, potentially compromising the diagnostic precision of BMD for subclinical bone demineralization. A total of 205 women aged 19 to 37 underwent anthropometric measurements and hormonal tests. BMD was determined using DXA, and TBS values were computed from the lumbar spine L1-L4 segment. The multivariate analysis findings suggest that BMD might not be determined by hormones. The relationship between TBS and TSH was statistically significant in the univariate analysis, which indicates the efficacy of further studies to determine the link between TBS and specific hormones. Analyzing the strength of the correlation between TBS and hormones in the univariate analysis shows which factors are worth considering in further analyses. This makes it possible to create better techniques that will help identify young women who are at a higher risk of developing osteoporosis.

Trabecular Bone Score Improves Fracture Risk Discrimination in Postmenopausal Rheumatoid Arthritis Patients Receiving Glucocorticoids

Background

Bone mineral density (BMD) might not be a sensitive tool for predicting osteoporotic fracture risk among patients with rheumatoid arthritis (RA), especially when receiving glucocorticoids. Trabecular bone score (TBS), which has emerged as a new assessment technique representing bone microarchitecture and strength, may be considered an alternative approach.

Materials and Methods

In this cross-sectional analytical study, postmenopausal RA patients receiving glucocorticoids were identified from the postmenopause BMD database. The database included clinical data of postmenopausal outpatients who had at least one BMD measurement between January 2014 and December 2017. TBS was calculated from lumbar spine BMD with the microarchitecture assessment software. The presence of osteoporotic fractures, either vertebral or non-vertebral, was identified at the time of BMD measurement.

Results

A total of 64 postmenopausal RA patients receiving glucocorticoids were included. The TBS values were inversely associated with osteoporotic fractures, with a TBS cut-off of less than 1.24, showing the best accuracy with a sensitivity of 79% and a specificity of 84% in discriminating fractures. This newly proposed TBS threshold combined with a BMD T-score of -2.5 or less demonstrated a greater area under receiver operating characteristic curve in identifying patients with osteoporotic fractures than the BMD threshold alone (p value = 0.003).

Conclusion

The reduction in TBS was associated with an osteoporotic fracture in postmenopausal RA patients receiving glucocorticoids. Combining TBS and BMD in these patients incrementally improves fracture risk discrimination and may serve as a supplementary tool in identifying patients at greatest risk of osteoporotic fracture.

Evaluation of bone-related mechanical properties in female patients with long-term remission of Cushing's syndrome using quantitative computed tomography-based finite element analysis

BACKGROUND

Hypercortisolism in Cushing's syndrome (CS) is associated with bone loss, skeletal fragility, and altered bone quality. No studies evaluated bone geometric and strain-stress values in CS patients after remission thus far.

PATIENTS AND METHODS

Thirty-two women with CS in remission (mean age [±SD] 51 ± 11; body mass index [BMI], 27 ± 4 kg/m2; mean time of remission, 120 ± 90 months) and 32 age-, BMI-, and gonadal status-matched female controls. Quantitative computed tomography (QCT) was used to assess volumetric bone mineral density (vBMD) and buckling ratio, cross-sectional area, and average cortical thickness at the level of the proximal femur. Finite element (FE) models were generated from QCT to calculate strain and stress values (maximum principal strain [MPE], maximum strain energy density [SED], maximum Von Mises [VM], and maximum principal stress [MPS]). Areal BMD (aBMD) and trabecular bone score (TBS) were assessed by dual-energy X-ray absorptiometry (2D DXA).

RESULTS

Trabecular vBMD at total hip and trochanter were lower in CS as compared with controls (P < .05). Average cortical thickness was lower, and buckling ratio was greater in CS vs controls (P < .01). All strain and stress values were higher in CS patients vs controls (P < .05). 2D DXA-derived measures were similar between patients and controls (P > .05). Prior hypercortisolism predicted both VM (β .30, P = .014) and MPS (β .30, P = .015), after adjusting for age, BMI, menopause, delay to diagnosis, and duration of remission.

CONCLUSIONS

Women with prior hypercortisolism have reduced trabecular vBMD and impaired bone geometrical and mechanical properties, which may contribute to an elevated fracture risk despite long-term remission.

High prevalence of vertebral fractures associated with preoperative cortisol levels in patients with recent diagnosis of Cushing disease

BACKGROUND/OBJECTIVE

Morphometric vertebral fractures (VFs) and osteopathy are prevalent and clinically significant complications of Cushing disease (CD). However whether they represent an early occurrence in the natural progression of the disease is an ongoing debate. This study aimed to assess the prevalence and determinants of VFs in patients newly diagnosed with CD.

PATIENTS AND METHODS

This cross-sectional case-control study recruited 75 newly diagnosed CD patients and compared them with a control group of individuals without pituitary disorders or secondary forms of osteoporosis. Demographic, clinical and biochemical data were collected. The VFs were assessed using preoperative lateral chest radiography.

RESULTS

We found a significantly higher prevalence of VFs in the CD group than in the control group (58.7% vs. 14.5%; P < 0.001). Among the CD patients with VFs, 27 (61.4%) showed moderate/severe VFs. The CD patients with VFs had significantly higher preoperative 8 am serum cortisol (8ASC) levels than those without VFs (P < 0.001). The preoperative 4 pm adrenocorticotropic hormone (ACTH) levels (P = 0.031), preoperative 0 am ACTH levels (P = 0.021) and systolic blood pressure were slightly higher in CD patients with VFs than in those without VFs (P = 0.028). A binary multiple logistic analysis showed that 8ASC was an independent predictor of VF risk (P = 0.003). The optimal cut-off value of the preoperative serum 8ASC level for predicting VFs was 22.18 ng/mL.

CONCLUSIONS

This is the first study reporting a high prevalence of radiologic VFs in recently diagnosed CD patients. VFs may represent an early manifestation of CD and may be related to cortisol levels. Therefore, VF assessment should be included in the workup during CD diagnosis.

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.

The Significance of Dual-Energy X-ray Absorptiometry (DXA) Examination in Cushing's Syndrome-A Systematic Review

In recent years, the usefulness of dual-energy X-ray absorptiometry (DXA) as a valuable complementary method of assessing the content and distribution of adipose and lean tissue as well as bone mineral density and estimating the risk of fractures has been increasingly confirmed. The diagnosis and treatment of Cushing's syndrome remain challenging, and monitoring the effects of treatment is often necessary. DXA tests offer a potential solution to many problems related to the availability of a quick, detailed, and reliable analysis of changes in the content and distribution of individual body composition components. The article discusses total body DXA scans (FMI, VAT, ALMI), lumbar spine scans (VFA, TBS), and osteoporosis scans (BMD, T-score, Z-score)-all are of potential interest in Cushing's syndrome. The article discusses the use of the most important indicators obtained from a DXA test (FMI, VAT, ALMI, BMD, T-score, Z-score, VFA, TBS) and their clinical significance in Cushing's syndrome was verified. The literature from the last decade was used for the study, available in MEDLINE, Web of Science, and ScienceDirect.

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.

Trabecular bone score, bone marrow fat and vertebral fractures in cushing syndrome

OBJECTIVE

Prediction of fragility fractures in Cushing syndrome (CS) is a challenge since dual energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) does not capture all the alterations in bone microstructure induced by glucocorticoid excess. In this study we investigated the relationship between trabecular bone score (TBS), bone marrow fat (BMF) and vertebral fractures (VFs) in endogenous CS.

DESIGN

Cross-sectional.

METHODS

Thirty subjects (7 M and 23 F, mean age 44.8 ± 13.4 yrs, range: 25-71) with active hypercortisolism were evaluated for VFs by quantitative morphometry, BMD and TBS by lumbar spine DXA and BMF by single-voxel magnetic resonance spectroscopy of vertebral body of L3.

RESULTS

Subjects with VFs (17 cases; 56.7%) had higher BMF (P = 0.014) and lower BMD T-score (P = 0.012) and TBS (P = 0.004) as compared to those without VFs. Prevalence of VFs resulted to be significantly higher in individuals with impaired TBS as compared to those with normal TBS (77.8% vs. 25.0%; P = 0.008). Among patients with VFs, only 6 (35.3%) had either osteoporosis or "low BMD for age". In logistic regression analysis, impaired TBS maintained the significant association with VFs [odds ratio (OR) 6.60, 95% C.I. 1.07-40.61; P = 0.042] independently of BMF (OR 1.03, 95% C.I. 0.99-1.08; P = 0.152).

CONCLUSIONS

TBS might be more accurate than BMF in identifying subjects with active CS and skeletal fragility at risk of VFs.

SIGNIFICANCE STATEMENT

Excess in glucocorticoids is associated with alterations in bone remodeling and metabolism, leading to fragility fractures regardless of bone mineral density, making more challenging for the clinician the identification of high-risk population and the definition of preventing strategies. In this context, instrumental parameters suggestive of bone quality alterations and predictive of increased fracture risk are needed. In this study, we found CS patients to have bone quality alterations as indicated by the decreased trabecular bone score and increased bone marrow fat, as measured by DEXA and MRI respectively. Both parameters were associated with high risk of VFs, and were inversely correlated, although TBS seems to be more accurate than BMF in fractures prediction in this clinical setting.

Vertebral Fractures in Acromegaly: A Systematic Review

INTRODUCTION

Acromegaly is characterized by a very particular alteration of bone microarchitecture, leading to increased vertebral fragility. However, due to inconsistent and insufficient evidence, no guidelines are available for the evaluation of this osteopathy.

METHODS

We performed a literature review of studies published between 1968 and January 2022 on the PubMed and SCOPUS databases using the terms "acromegaly" and "vertebral fractures". Twenty-four studies were found eligible for inclusion, published between June 2005 and November 2021. Included studies evaluated acromegaly patients, who were assessed for the presence of vertebral fractures. We excluded case reports, reviews, meta-analyses, letters to the editor, articles not written in English, and research performed on the same set of patients without significant differences in study design. Risk of bias was avoided by following the ROBIS risk of bias recommendations. We executed rigorous data collection, and the results are depicted as a narrative overview, but also, as statistical synthesis. Limitations of the evidence presented in the study include study heterogeneity, small sample sizes, and a small number of prospective studies with short follow-up.

FINDINGS

Data regarding vertebral fractures (VFs) in acromegaly and their influencing factors are variable. Twenty-four studies were included, nine out of which had a prospective design. The smallest group of acromegaly patients had 18 subjects and the largest included 248 patients. Prevalence ranges between 6.5% and 87.1%, although most studies agree that it is significantly higher than in controls. VFs also have a higher incidence (between 5.6% and 42%) and are more frequently multiple (between 46.15% and 71%). Evidence shows that disease activity and active disease duration are influencing factors for the prevalence and incidence of VFs. Nonetheless, hypogonadism does not seem to influence the frequency of VFs. While reports are conflicting regarding the use of bone mineral density in acromegaly, evidence seems to be slightly in favor of it not being associated with VFs. However, trabecular bone score is significantly lower in fractured patients, although no prospective studies are available.

INTERPRETATION

Vertebral fractures evaluation should be performed with regularity in all acromegalic patients, especially in the presence of active disease. Disease activity is an important determinant of vertebral fracture incidence and prevalence, although hypogonadism is less so. To clarify the predictive value of both BMD and TBS for vertebral fractures, additional, larger, prospective studies are necessary.

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.

Novel approaches to bone comorbidity in Cushing's disease: an update

Skeletal complications are frequent and clinically relevant findings in Cushing's disease (CD) since an uncoupled suppressed bone formation and enhanced bone resorption leads to a marked skeletal damage with a rapid increase of fracture risk. Reduced Bone Mineral Density (BMD) has been consistently reported and osteopenia or osteoporosis are typical findings in patients with CD. Vertebral Fractures (VFs) are frequently reported and may occur even in patients with an only mild reduction of BMD, representing nowadays a still under- or misdiagnosed comorbidity of these patients being frequently asymptomatic. A novel approach combining different available tools such as BMD evaluation and vertebral morphometry, in order to improve diagnosis, management, and follow-up of bone comorbidity in all patients affected by CD, is needed. This approach is foreseen to be a crucial part of management of patients with CD, particularly in Pituitary Tumor Center of Excellence since VFs, the landmark of the bone involvement, may occur early in the history of the disease and may represent a relevant risk factor for further fractures, reduced quality of life and survival and need for pharmacologic prevention and treatment.

Prevention and Treatment of Glucocorticoid-Induced Osteoporosis in Adults: Consensus Recommendations From the Belgian Bone Club

Glucocorticoids are effective immunomodulatory drugs used for many inflammatory disorders as well as in transplant recipients. However, both iatrogenic and endogenous glucocorticoid excess are also associated with several side effects including an increased risk of osteoporosis and fractures. Glucocorticoid-induced osteoporosis (GIOP) is a common secondary cause of osteoporosis in adults. Despite availability of clear evidence and international guidelines for the prevention of GIOP, a large treatment gap remains. In this narrative review, the Belgian Bone Club (BBC) updates its 2006 consensus recommendations for the prevention and treatment of GIOP in adults. The pathophysiology of GIOP is multifactorial. The BBC strongly advises non-pharmacological measures including physical exercise, smoking cessation and avoidance of alcohol abuse in all adults at risk for osteoporosis. Glucocorticoids are associated with impaired intestinal calcium absorption; the BBC therefore strongly recommend sufficient calcium intake and avoidance of vitamin D deficiency. We recommend assessment of fracture risk, taking age, sex, menopausal status, prior fractures, glucocorticoid dose, other clinical risk factors and bone mineral density into account. Placebo-controlled randomized controlled trials have demonstrated the efficacy of alendronate, risedronate, zoledronate, denosumab and teriparatide in GIOP. We suggest monitoring by dual-energy X-ray absorptiometry (DXA) and vertebral fracture identification one year after glucocorticoid initiation. The trabecular bone score might be considered during DXA monitoring. Extended femur scans might be considered at the time of DXA imaging in glucocorticoid users on long-term (≥ 3 years) antiresorptive therapy. Bone turnover markers may be considered for monitoring treatment with anti-resorptive or osteoanabolic drugs in GIOP. Although the pathophysiology of solid organ and hematopoietic stem cell transplantation-induced osteoporosis extends beyond GIOP alone, the BBC recommends similar evaluation, prevention, treatment and follow-up principles in these patients. Efforts to close the treatment gap in GIOP and implement available effective fracture prevention strategies into clinical practice in primary, secondary and tertiary care are urgently needed.

Recurrent Metatarsal Fractures in a Patient With Cushing Disease: A Case Report

Cushing syndrome (CS) can result from excess exposure to exogenous or endogenous glucocorticoids. The most common endogenous cause of CS is an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma, known as Cushing disease (CD). Patients typically present with characteristics including truncal obesity, moon facies, facial plethora, proximal muscle weakness, easy bruising, and striae. Insufficiency fractures of the metatarsals are a rare presentation for CS. A 39-year-old premenopausal woman presented to the orthopedic outpatient clinic with recurrent metatarsal fractures and no history of trauma. A metabolic bone disease was suspected, and after further evaluation by endocrinology services, the CD was diagnosed. Surgical resection was performed, and pathology confirmed the presence of a pituitary adenoma. Multiple, recurrent, non-traumatic metatarsal fractures can be the initial presentation of CD in a premenopausal woman.

Regulation of bone mass in endocrine diseases including diabetes

Hormonal regulation plays a key role in determining bone mass in humans. Both skeletal growth and bone loss in health and disease is critically controlled by endocrine factors and low bone mass is a feature of both excess and deficiency of a broad range of hormones. This article explores the impact of diabetes and thyroid, parathyroid, sex steroid and growth hormone disorders on bone mass and fracture risk. Evidence for current management strategies is provided along with suggested practice points and gaps in knowledge for future research.

Dilemmas in the Management of Osteoporosis in Younger Adults

Osteoporosis in premenopausal women and men younger than 50 years is challenging to diagnose and treat. There are many barriers to optimal management of osteoporosis in younger adults, further enhanced by a limited research focus on this cohort. Herein we describe dilemmas commonly encountered in diagnosis, investigation, and management of osteoporosis in younger adults. We also provide a suggested framework, based on the limited available evidence and supported by clinical experience, for the diagnosis, assessment, and management of osteoporosis in this cohort. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

DXA parameters, Trabecular Bone Score (TBS) and Bone Mineral Density (BMD), in fracture risk prediction in endocrine-mediated secondary osteoporosis

Osteoporosis, a disease characterized by low bone mass and alterations of bone microarchitecture, leading to an increased risk for fragility fractures and, eventually, to fracture; is associated with an excess of mortality, a decrease in quality of life, and co-morbidities. Bone mineral density (BMD), measured by dual X-ray absorptiometry (DXA), has been the gold standard for the diagnosis of osteoporosis. Trabecular bone score (TBS), a textural analysis of the lumbar spine DXA images, is an index of bone microarchitecture. TBS has been robustly shown to predict fractures independently of BMD. In this review, while reporting also results on BMD, we mainly focus on the TBS role in the assessment of bone health in endocrine disorders known to be reflected in bone.

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

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

Assessment of non-traumatic vertebral fractures in Cushing's syndrome patients

PURPOSE

Hypercortisolism has detrimental effects on bone metabolism with the consequences of bone loss and bone fractures. We aimed to evaluate the frequency of vertebral fragility fractures and to determine the factors associated with Cushing's syndrome (CS).

METHODS

A total of 135 patients diagnosed with Cushing's syndrome [108 patients with Cushing's disease and 27 patients with adrenocortical adenoma] and 107 healthy controls were included in this cross-sectional study. The available clinical, laboratory, and radiologic data of patients with CS were recorded, retrospectively. Lateral vertebral radiograms were evaluated for vertebral fragility fractures according to Genant's semi-quantitative method. Bone mineral density (BMD) was determined using a Dual-energy X-ray absorptiometry (DEXA).

RESULTS

Vertebral fragility fractures (VFs) were observed in 75.3% (n = 61) of the patients. The median number of VFs was six (min-max: 2-12). All patients with vertebral fractures had thoracic VF, and 50.7% of the patients had lumbar fragility fractures. Thirty-three (40.7%) patients with vertebral fractures had normal bone densitometry values. Osteoporosis and osteopenia were observed in 16.2% and 40.7% of the patients, respectively. The duration of active disease, the presence of ACTH-secreting pituitary adenoma, and 24-h urinary cortisol did not influence the presence of vertebral fractures. Vertebral fractures were independently associated with age, FSH, LH levels, and lumbar BMD (R² = 68.18%, p = 0.028). The femoral neck BMD (but not lumbar BMD) was independently associated with age, BMI, and PTH levels (R² = 48.48%, p < 0.001).

CONCLUSION

Vertebral fracture frequency was higher in CS patients. Most of the patients with vertebral fractures had multiple fractures. Although low lumbar BMD was associated with VF, patients with CS with normal bone densitometry could experience VF. Vertebral radiograph evaluations as a part of routine evaluation for silent vertebral fractures may help to prevent further fractures in patients with CS.

Bone mineral density and trabecular bone score in patients with 21-hydroxylase deficiency after glucocorticoid treatment

OBJECTIVE

Patients with 21-hydroxylase deficiency (21-OHD) are at risk of reduced bone mineral density (BMD) and fracture due to long-term glucocorticoid treatment. Trabecular bone score (TBS) is complementary to conventional BMD as a marker for bone quality in patients with glucocorticoid-induced osteoporosis. The purpose of this study is to evaluate the BMD and TBS in a cohort of patients with 21-OHD and analyse factors related to TBS.

DESIGN

An observational study.

PATIENTS

A total of 46 21-OHD adult patients treated with glucocorticoid for over 10 years who visited Peking Union Medical College Hospital between 2015 and 2019 were recruited. Eight male patients included in this study were all under 50 years old, and 38 female patients were all premenopausal.

MEASUREMENTS

Diagnosis was confirmed by multiplex ligation-dependent probe amplification combined with sequencing. Data were collected on physical characteristics, serum hormones and glucocorticoid treatment. Skeletal quality was evaluated by BMD and TBS, and factors related to TBS were analysed.

RESULTS

Among the 46 patients, 2 (4.3%) had low BMD (Z-score ≤ -2), while 11 (23.9%) patients had low TBS (degraded or partially degraded microarchitecture). The proportion of bone abnormality evaluated by TBS was higher than that by BMD (p < .001). Patients with lower TBS had significantly higher daily hydrocortisone dosage (p = .009 for males; p = .019 for females). TBS value was negatively correlated with daily hydrocortisone dosage (r = -.317, p = .026), and positively correlated with BMI in female patients (r = .345, p = .034). And there was a negative correlation between TBS value and the current age in male patients (r = -.741, p = .036). The distribution of genotypes (p = 1.000 for male; p = .567 for female) or phenotypes (p = .486 for male; p = .075 for female) had no statistical difference in patients with normal or abnormal TBS.

CONCLUSIONS

Approximately 24% of patients with 21-OHD had abnormal microarchitecture of their bone in our study, and TBS score was negatively correlated with daily glucocorticoid dosage in patients. TBS may be used alongside conventional BMD as a complementary marker for bone evaluation in 21-OHD patients.

Association of urinary free cortisol with bone formation in patients with mild autonomous cortisol secretion

CONTEXT

Mild autonomous cortisol secretion (ACS) is associated with an increased risk of vertebral fractures (VFx). However, the influence of this condition on bone turnover or its association with mild ACS is still controversial.

OBJECTIVE

This study aimed to evaluate the impact of mild ACS on bone quality among patients living with the disease.

DESIGN AND SETTING

A retrospective study was conducted using data from 55 mild ACS and 12 nonfunctioning adrenal tumour (NFT) patients who visited Chiba University Hospital, Japan, from 2006 to 2018.

PATIENTS AND MAIN OUTCOME MEASURES

We analysed clinical features and bone-related factors, including bone mineral density (BMD) and VFx, performed blood tests to assess bone metabolism markers in patients with mild ACS and NFT, and assessed the associations between bone-related markers and endocrinological parameters in patients with mild ACS.

RESULTS

No significant differences between mild ACS and NFT patients were observed with respect to the presence or absence of VFx and BMD. Urinary free cortisol (UFC) was higher in mild ACS patients with VFx than those without (p = .037). The T-score and young adult mean (YAM) of the BMD of the femoral neck in mild ACS patients with a body mass index <25 were positively correlated with dehydroepiandrosterone sulphate levels (ρ: 0.42, p = .017; ρ: 0.40, p = .024, respectively). Pearson's correlation analysis showed that bone-specific alkaline phosphatase was negatively correlated with UFC in the patients with mild ACS (ρ: -0.37, p = .026).

CONCLUSIONS

These results suggest that urinary free cortisol may be useful for predicting bone formation in mild ACS patients.

Osteopathy in mild adrenal Cushing's syndrome and Cushing disease

Pathophysiology and effects of endogenous glucocorticoid (GC) excess on skeletal endpoints as well as awareness and management of bone fragility are reviewed. Cushing's syndrome (CS) increase the risk of fracture affecting prevalently bone quality. Bone antiresorptive agents (SERMs, bisphosphonates and denosumab) as well as teriparatide increase bone mineral density and in some instances reduce fracture risk. Awareness and management of bone health in CS can be improved.

Thyroid Hormones, Glucocorticoids, Insulin, and Bone

Several endocrine systems have important effects on bone tissue. Thyroid hormones are essential for normal growth and development. Excess of these hormones will result in clinically significant changes that may require intervention. Glucocorticoids also have a marked effect on bone metabolism by several pathways. Their endogenous or exogenous excess will induce pathological processes that might elevate the risk of fractures. Insulin and the carbohydrate metabolism elicit a physiological effect on bone; however, the lack of insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) have deleterious influence on bone tissue.

Physical and lifestyle factors associated with trabecular bone score values

TBS is associated with age, weight, childhood physical activity, and BMD in men and age, height, BMD, and mobility in women.

INTRODUCTION

Trabecular bone score (TBS) indirectly assesses trabecular microarchitecture at the lumbar spine, providing complementary information to areal BMD. Many studies have investigated the relationships between BMD and lifestyle factors known to affect bone, but such research is limited for TBS. The aim of this study was to assess the relationship between TBS and lifestyle factors in Australian men and women.

METHODS

This cross-sectional study involved 894 men and 682 women (ages 24-98 years) enrolled in the Geelong Osteoporosis Study. TBS was assessed by analysis of lumbar spine DXA scans (Lunar Prodigy) using TBS iNsight software (Version 2.2). Bivariate and multivariable linear regression models were used to explore the associations between TBS and physical and lifestyle factors, including anthropometry, alcohol consumption, childhood physical activity, mobility, smoking status, prior low trauma fracture, medication use, and intakes of calcium and vitamin D.

RESULTS

In bivariate regression modelling, low mobility and the use of antiresorptive medication were associated with lower TBS in both men and women. Low childhood physical activity was also associated with lower TBS in men. Prior fracture, use of glucocorticosteroids, and total calcium intake were also associated with lower TBS in women. The final adjusted model for men included age, weight, childhood physical activity, and BMD, and for women, age, height, BMD, and mobility. No interaction terms were identified in the models.

CONCLUSIONS

Lower TBS is associated with older age, increased weight, low childhood physical activity, and lower BMD in men and older age, shorter stature, lower BMD, and low mobility in women.

Glucocorticoids and Trabecular Bone Score

TBS (Trabecular Bone Score) is the latest tool for clinicians to evaluate bone micro-architecture based on a pixel greyscale, which is provided by lumbar dual-energy X-ray absorptiometry (DXA). Its use enhances fracture prediction in addition to DXA-BMD (Bone Mineral Density). This is independent of fracture risk assessment (FRAX) and DXA results. We present a narrative review regarding the connection between TBS and Glucocorticoids (GC), either as a drug used for different conditions or as a tumor-produced endogenous excess. TBS is a better discriminator for GC-induced vertebral fractures compared to DXA-BMD. This aspect is similarly available for patients with osteoporosis diagnosed by DXA. TBS is inversely correlated with the cumulative dose of GC (systemic or inhaled), with disease duration, and positively correlated with respiratory function in patients with asthma. Low TBS values are found in females with a T-score at the hip within the osteoporosis range, with diabetes mellitus, or who use GC. Lumbar TBS is a screening tool in menopausal women with type 2 diabetes mellitus. TBS is an independent parameter that provides information regarding skeleton deterioration in diabetic patients receiving GC therapy in a manner complementary to DXA-BMD. TBS might become an essential step regarding the adrenalectomy decision in patients with adrenal incidentaloma in whom autonomous cortisol secretion might damage bone micro-architecture. TBS currently represents a standard tool of fracture risk evaluation in patients receiving GC therapy or with endogenous Cushing's syndrome, a tool easy to be applied by different practitioners since GCs are largely used.

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.

Decreased Trabecular Bone Score in Patients With Active Endogenous Cushing's Syndrome

INTRODUCTION

The impairment in bone microarchitecture and reduced bone quality are relevant mechanisms underlying the increased fracture risk in Cushing's syndrome (CS). The trabecular bone score (TBS) is a relatively novel textural index of bone microarchitecture.

PURPOSE

The objective of the study was to compare TBS, bone mineral density (BMD), and fracture risk in patients with endogenous CS to controls. We have investigated the association of TBS with anthropometric parameters and 25(OH) vitamin D concentrations.

MATERIALS AND METHODS

The study group comprised 19 consecutive patients with CS (14 women and 5 men; mean age 45.84 ± 13.15 years) and sex-, age-matched 36 controls (25 women and men; mean age 52.47 ± 8.98 years). Anthropometric parameters, biochemical and hormonal data were compared between groups. Lumbar spine (L1-L4) and femoral neck BMD (LS BMD, FN BMD) measurements were performed. TBS values were obtained from lumbar spine DXA images.

RESULTS

TBS was significantly lower in patients with CS compared to controls (p = 0.0002). The 10-year probability of hip fracture and the 10-year probability of a major osteoporotic fracture were significantly higher in the CS group than in controls (p = 0.03, p < 0.0001, respectively). All subjects from the CS group with fractures had low TBS value (degraded microarchitecture). TBS correlated negatively with the duration of disease in patients with CS (r = -0.590 p = 0.008).

CONCLUSIONS

The patients with active CS have altered bone microstructure as indicated by the decreased TBS and are at higher risk of hip and a major osteoporotic fractures. TBS seems to be a very important analytical tool facilitating fracture risk assessment in endogenous hypercortisolism.

High bone marrow fat in patients with Cushing's syndrome and vertebral fractures

PURPOSE

The evaluation of skeletal fragility in Cushing's syndrome (CS) is a clinical challenge, since dual-energy X-ray absorptiometry (DXA) does not capture abnormalities in bone microstructure induced by glucocorticoid excess. Hypercortisolism was shown to increase bone marrow adiposity, but it is still unknown whether high bone marrow fat (BMF) as measured by vertebral magnetic resonance spectroscopy may predict fracture risk in this clinical setting. In this cross-sectional study, we evaluated the association between BMF and vertebral fractures (VFs) in patients with CS.

METHODS

Twenty patients (5 M, age 44 ± 13 years) with active CS were evaluated for morphometric VFs, lumbar spine BMF, and bone mineral density (BMD). Fifteen healthy volunteers (4 M, age 43 ± 12 years) acted as control group for BMF evaluation.

RESULTS

BMF was significantly higher in CS patients vs. controls (52.0% vs. 27.0%, p < 0.01), and was directly correlated with patients' age (p = 0.03), 24-hours urine-free cortisol (p = 0.03), midnight serum cortisol (p = 0.02), and serum CTX (p = 0.01). Patients with VFs (13 cases) showed significantly higher BMF vs. patients without VFs (65.0% vs. 24.0%, p = 0.03). Fractured patients with either normal BMD or osteopenia showed comparable BMF to fractured patients with either osteoporosis or low BMD for age (p = 0.71). When the analysis was restricted to patients with normal BMD or osteopenia, VFs were still significantly associated with higher BMF (p = 0.05).

CONCLUSIONS

This study provides a first evidence that vertebral adiposity may be a marker of hypercortisolism-induced skeletal fragility and measurement of spine BMF could have a role in the diagnostic work-up for the assessment of fracture risk in CS.

Toward a Diagnostic Score in Cushing's Syndrome

Cushing's syndrome (CS) is a classical rare disease: it is often suspected in patients who do not have the disease; at the same time, it takes a mean of 3 years to diagnose CS in affected individuals. The main reason is the extreme rarity (1-3/million/year) in combination with the lack of a single lead symptom. CS has to be suspected when a combination of signs and symptoms is present, which together make up the characteristic phenotype of cortisol excess. Unusual fat distribution affecting the face, neck, and trunk; skin changes including plethora, acne, hirsutism, livid striae, and easy bruising; and signs of protein catabolism such as thinned and vulnerable skin, osteoporotic fractures, and proximal myopathy indicate the need for biochemical screening for CS. In contrast, common symptoms like hypertension, weight gain, or diabetes also occur quite frequently in the general population and per se do not justify biochemical testing. First-line screening tests include urinary free cortisol excretion, dexamethasone suppression testing, and late-night salivary cortisol measurements. All three tests have overall reasonable sensitivity and specificity, and first-line testing should be selected on the basis of the physiologic conditions of the patient, drug intake, and available laboratory quality control measures. Two normal test results usually exclude the presence of CS. Other tests and laboratory parameters like the high-dose dexamethasone suppression test, plasma ACTH, the CRH test, and the bilateral inferior petrosal sinus sampling are not part of the initial biochemical screening. As a general rule, biochemical screening should only be performed if the pre-test probability for CS is reasonably high. This article provides an overview about the current standard in the diagnosis of CS starting with clinical scores and screenings, the clinical signs, relevant differential diagnoses, the first-line biochemical screening, and ending with a few exceptional cases.

Cushing's disease in older patients: Presentation and outcome

BACKGROUND

To define the symptoms, signs and treatment outcomes in a population of older patients with Cushing's disease (CD).

METHODS

We analysed the clinical presentation and treatment outcomes in 45 CD patients older than 60 years, in comparison with 90 CD patients younger than 60, and a control group of 45 older patients with nonfunctioning pituitary adenomas. We reviewed preoperative clinical characteristics, medical comorbidities, imaging findings and endocrine testing as well as surgical and endocrine outcomes.

RESULTS

Older CD patients had significantly lower body mass index (BMI) (P = 0.031), were more likely to have muscle wasting (P = 0.006) and women were less likely to have hirsutism (P = 0.033). Older patients with CD had more medical comorbidities than younger patients, which correlated with a higher ASA grade (P < 0.001), but the surgical complication rates were similar in both groups. Surgical remission was achieved in 38/45 (84.4%) older patients and 78/90 (86.7%) younger patients (P = NS). Recurrent disease was more frequent in younger patients (19.2%) in comparison with older patients (2.6%, P = 0.019).

CONCLUSIONS

Older patients with CD appear to have a distinct phenotype with a more catabolic picture, including a lower BMI and greater prevalence of muscle wasting. Surgical outcomes are similar without a significant age-related increase in complications.

Glucocorticoids and Bone: Consequences of Endogenous and Exogenous Excess and Replacement Therapy

Osteoporosis associated with long-term glucocorticoid therapy remains a common and serious bone disease. Additionally, in recent years it has become clear that more subtle states of endogenous glucocorticoid excess may have a major impact on bone health. Adverse effects can be seen with mild systemic glucocorticoid excess, but there is also evidence of tissue-specific regulation of glucocorticoid action within bone as a mechanism of disease. This review article examines (1) the role of endogenous glucocorticoids in normal bone physiology, (2) the skeletal effects of endogenous glucocorticoid excess in the context of endocrine conditions such as Cushing disease/syndrome and autonomous cortisol secretion (subclinical Cushing syndrome), and (3) the actions of therapeutic (exogenous) glucocorticoids on bone. We review the extent to which the effect of glucocorticoids on bone is influenced by variations in tissue metabolizing enzymes and glucocorticoid receptor expression and sensitivity. We consider how the effects of therapeutic glucocorticoids on bone are complicated by the effects of the underlying inflammatory disease being treated. We also examine the impact that glucocorticoid replacement regimens have on bone in the context of primary and secondary adrenal insufficiency. We conclude that even subtle excess of endogenous or moderate doses of therapeutic glucocorticoids are detrimental to bone. However, in patients with inflammatory disorders there is a complex interplay between glucocorticoid treatment and underlying inflammation, with the underlying condition frequently representing the major component underpinning bone damage.

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.

Assessment of vertebral microarchitecture in overt and mild Cushing's syndrome using trabecular bone score

OBJECTIVE

Osteoporotic fractures associated with Cushing's syndrome (CS) may occur despite normal bone mineral density (BMD). Few studies have described alterations in vertebral microarchitecture in glucocorticoid-treated patients and during CS. Trabecular bone score (TBS) estimates trabecular microarchitecture from dual-energy X-ray absorptiometry acquisitions. Our aim was to compare vertebral BMD and TBS in patients with overt CS and mild autonomous cortisol secretion (MACE), and following cure of overt CS.

SETTING

University Hospital.

DESIGN

Monocentric retrospective cross-sectional and longitudinal studies of consecutive patients.

PATIENTS

A total of 110 patients were studied: 53 patients had CS (35, 11 and 7 patients with Cushing's disease, bilateral macronodular adrenal hyperplasia and ectopic ACTH secretion respectively); 39 patients had MACE (10 patients with a late post-operative recurrence of Cushing's disease and 29 patients with adrenal incidentalomas); 18 patients with non-secreting adrenal incidentalomas. 14 patients with overt CS were followed for up to 2 years after cure.

RESULTS

Vertebral osteoporosis at BMD and degraded microarchitecture at TBS were found in 24% and 43% of patients with CS, respectively (P < .03). As compared to patients with nonsecreting incidentalomas, patients with MACE had significantly decreased TBS (P < .04) but not BMD. Overt fragility fractures tended to be associated with low TBS (P = .07) but not with low BMD. TBS, but not BMD values, decreased with the intensity of hypercortisolism independently of its aetiology (P < .01). Following remission of CS, TBS improved more markedly and rapidly than BMD (10% vs 3%, respectively; P < .02).

CONCLUSION

Trabecular bone score may be a promising, noninvasive, widely available and inexpensive complementary tool for the routine assessment of the impact of CS and MACE on bone in clinical practice.

Morbidity of Cushing's Syndrome and Impact of Treatment

Cortisol excess in Cushing's syndrome is associated with metabolic, cardiovascular, and cognitive alterations, only partially reversible after resolution of hypercortisolism. Elevated cardiovascular risk may persist after eucortisolism has been achieved. Fractures and low bone mineral density are also described in Cushing's syndrome in remission. Hypercortisolism may induce irreversible structural and functional changes in the brain, leading to neuropsychiatric disorders in the active phase of the disease, which persist. Sustained deterioration of the cardiovascular system, bone remodeling, and cognitive function along with neuropsychological impairment are associated with high morbidity and poor quality of life before and after remission.

Effects of endogenous hypercortisolism on bone mRNA and microRNA expression in humans

Hypercortisolism in humans suppresses osteoblastogenesis and osteoblast function through the upregulation of Wnt-signaling antagonists (sclerostin, Dkk1) and changes in microRNAs levels (miR-125b-5p, miR-218-5p, miR-34a-5p, miR-188-3p, miR-199a-5p) which are associated with mesenchymal stem-cell commitment to adipocytes or cartilage cells over the osteoblasts.

INTRODUCTION

The purpose of this study was to evaluate the responses of bone to chronic glucocorticoid (GC) excess by measuring the levels of selected mRNA and microRNA (miR) in bone samples of patients with Cushing's disease (CD).

METHODS

Bone samples were obtained during transsphenoidal adenomectomy from the sphenoid bone (sella turcica) from 16 patients with clinically and biochemically evident CD and 10 patients with clinically non-functioning pituitary adenomas (NFPA) matched by sex, age, and body mass index. Quantitative polymerase chain reactions (qPCR) were used to examine the expression of genes (mRNA and miRs) known to be involved in bone remodeling regulation based on studies in animals and cell culture.

RESULTS

Hypercortisolism was associated with the downregulation of genes involved in osteoblast function and maturation (ACP5, ALPL, BGLAP, COL1A1, COL1A2, BMP2, RUNX2, TWIST1). An excess of GC caused increased expression of Wnt-signaling antagonists (Dkk1, SOST) and changes in the levels of miRs that are known to suppress osteoblastogenesis (miR-125b-5p, miR-218-5p, miR-34a-5p, miR-188-3p, miR-199a-5p) p < 0.05, q < 0.1. Interestingly, compensatory mechanisms were found in long-term hypercortisolism: upregulation of Wnt10b, LRP5, and LRP6; downregulation of SFRP4; changes in miRs involved in osteoblastogenesis (miR-210-5p, miR-135a-5p, miR-211, miR-23a-3p, miR-204-5p); and downregulation of genes associated with osteoclastogenesis. None of these changes prevented the suppression of bone formation.

CONCLUSIONS

An excess of endogenous GC in humans suppresses bone formation through the upregulation of Wnt-signaling antagonists and dysregulation of miRs involved in mesenchymal stem-cell commitment. Both Wnt-signaling antagonists and miRs seem to be promising targets for further research in therapeutic intervention in glucocorticoid-induced osteoporosis.

Trabecular Bone Score: A New DXA-Derived Measurement for Fracture Risk Assessment

Trabecular bone score (TBS) is a novel method that assesses skeletal texture from spine dual-energy X-ray absorptiometry (DXA) images. TBS improves fracture-risk prediction beyond that provided by DXA bone mineral density (BMD) and clinical risk factors, and can be incorporated to the Word Health Organization Fracture Risk Assessment tool (FRAX®) to enhance fracture prediction. There is insufficient evidence that TBS can be used to monitor treatment with bisphosphonates. TBS may be particularly helpful to assess fracture risk in diabetes. This article reviews technical and clinical aspects of TBS and its potential utility as a clinical tool to predict fracture risk.