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

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.

New Insights in the Pathophysiology, Epidemiology, and Response to Treatment of Osteoporotic Vertebral Fractures

CONTEXT

Vertebral fractures (VFs) make up an important but challenging group of fractures often caused by osteoporosis. Osteoporotic fractures pose unique diagnostic challenges in generally requiring imaging for diagnosis. The objective of this narrative mini-review is to provide an overview of these recent advances in our knowledge of VF pathophysiology and epidemiology with particular focus on endocrine diseases, prevention, and treatment.

EVIDENCE ACQUISITION

We searched PubMed on May 23, 2022, for studies of VFs in humans. Results were limited to papers available as full-text publications in English, published from 2020 and onward. This yielded 3457 citations. This was supplemented by earlier publications selected to add context to the recent findings.

EVIDENCE SYNTHESIS

Studies addressed VF risk in hyperthyreosis, hyperparathyroidism, acromegaly, Cushing syndrome, primary aldosteronism, and diabetes. For pharmaceutical treatment, new studies or analyses were identified for romosozumab and for weekly teriparatide. Several studies, including studies in the immediate pipeline, were intervention studies with vertebroplasty or kyphoplasty, including combination with stem cells or pharmaceuticals.

CONCLUSIONS

Endocrinologists should be aware of the high likelihood of osteoporotic VFs in patients with endocrine diseases. Though licensed treatments are able to substantially reduce the occurrence of VFs in patients with osteoporosis, the vast majority of recent or ongoing randomized controlled trials in the VF area focus on advanced invasive therapy of the fracture itself.

Acromegaly and the long-term fracture risk of the vertebra and hip: a national cohort study

In this national cohort study, the patients with acromegaly had significantly higher risks of clinical vertebral (HR 2.09 [1.58-2.78]) and hip (HR 2.52 [1.61-3.95]) fractures than the controls. The increased fracture risk in patients with acromegaly was time-dependent and was observed even during the early period of follow-up.

PURPOSE

Acromegaly is characterized by the overproduction of growth hormone (GH) and insulin-like growth factor-1 (IGF-1), both play important roles in regulating bone metabolism. We investigated the risk of vertebral and hip fractures in patients with acromegaly compared to age- and sex-matched controls.

METHODS

This nationwide population-based cohort study included 1,777 patients with acromegaly aged 40 years or older in 2006-2016 and 8,885 age- and sex-matched controls. A Cox proportional hazards model was used to estimate the adjusted hazard ratio (HR) [95% confidence interval].

RESULTS

The mean age was 54.3 years and 58.9% were female. For approximately 8.5 years of follow-up, the patients with acromegaly had significantly higher risks of clinical vertebral (HR 2.09 [1.58-2.78]) and hip (HR 2.52 [1.61-3.95]) fractures than the controls in the multivariate analyses. There were significant differences in the risks of clinical vertebral (P < 0.0001) and hip (P < 0.0001) fractures between the patients with acromegaly and the controls in the Kaplan-Meier survival analysis. The multivariable-adjusted HRs for clinical vertebral fractures comparing the patients with acromegaly with controls during and excluding the first 7 years of observation were 1.69 [1.15-2.49] and 2.70 [1.75-4.17], respectively. The HRs for hip fractures during and excluding the first 7 years of observation were 2.29 [1.25-4.18] and 3.36 [1.63-6.92], respectively.

CONCLUSIONS

The patients with acromegaly had a higher risk of hip fractures as well as clinical vertebral fractures than the controls. The increased fracture risk in patients with acromegaly was time-dependent and was observed even during the early period of follow-up.

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.

Prediction of vertebral fractures in cancer patients undergoing hormone deprivation therapies: reliability of who fracture risk assessment tool (frax) and bone mineral density in real-life clinical practice

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In females under estrogen-deprivation therapies, risk of vertebral fractures was associated with FRAX score for major fractures, with the best therapeutic threshold of 6.5%.

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In males under androgen-deprivation therapy, risk of vertebral fractures was high when BMD T-score was lower than −1.0 SD or when subjects were treated with abiraterone.

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High body mass index was an independent risk factor for vertebral fractures in males exposed to androgen-deprivation therapy.

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In the setting of hormonal deprivation therapies, FRAX and BMD thresholds were lower than those used in post-menopausal osteoporosis and primary male osteoporosis.

Background and Objective

Prediction of fractures in cancer survivors exposed to hormone-deprivation therapies (HDTs) is a challenge since bone loss is rapid and severe, and determinants of fractures in this setting are still largely unknown. In this study we investigated reliability of the WHO Fracture Risk Assessment Tool (FRAX) and bone mineral density (BMD) to identify subjects developing vertebral fractures during HDTs.

Design

Five-hundred-twenty-seven consecutive subjects (429 females with breast cancer, 98 males with prostate cancer; median age 61 years), under HDTs for at least 6 months, were evaluated for vertebral fractures by a radiological and morphometric approach, in relationship with FRAX score, body mass index (BMI), BMD, age and duration of HDTs.

Results

Vertebral fractures were found in 140 subjects (26.6%) and spine deformity index was significantly associated with duration of HDTs (rho 0.38; p < 0.001). Only in females, vertebral fractures were significantly associated with FRAX score for major fractures [OR 1.08; P < 0.001]. The best cut-off of FRAX score for major fractures, as calculated by receiving operating characteristic (ROC) analysis was 6.35%. In males, however, vertebral fractures were significantly and independently associated with BMI ≥ 25 Kg/m² (OR 17.63; P < 0.001), BMD T-score below −1.0 SD at any skeletal site (OR 7.79; P < 0.001) and gonadotropin-releasing hormone agonists (GnRHa) plus abiraterone treatment (OR 11.51; P = 0.001).

Conclusions

FRAX and BMD may be useful for predicting vertebral fractures in subjects undergoing HDTs, but the thresholds seem to be lower than those used in the general population. High BMI is a determinant of vertebral fractures in males under HDT.