Bone properties in patients with acromegaly: quantitative ultrasound of the heel

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Acromegaly: Clinical Care in Central and Eastern Europe, Israel, and Kazakhstan

Acromegaly is a rare condition typically caused by benign pituitary adenomas, resulting in excessive production of growth hormone. Clinical manifestations of acromegaly are diverse, varying from the overgrowth of body tissue to cardiovascular, metabolic, and osteoarticular disorders. Symptoms may emerge slowly, overlapping with other diseases and often involve many different healthcare specialists. In the last decade, efforts to provide an accurate and timely diagnosis of acromegaly have improved disease management and clinical experience. Despite this progress, marked differences in the diagnosis, treatment, and management of acromegaly exist from country-to-country. To address these inconsistencies in the region comprising Central and Eastern Europe, Israel, and Kazakhstan, a panel of acromegaly experts from 13 of these countries was convened. Acromegaly experts from each country provided available information on the approaches from their country, including regional treatment centers and multidisciplinary teams, treatment access, reimbursement and availability, and physician education, disease awareness, and patient advocacy. Across several areas of acromegaly management, divergent approaches were identified and discussed, including the provision of multidisciplinary care, approved and available treatments, and disease awareness programs. These were recognized as areas of potential improvement in the management of acromegaly, in addition to participation in national and regional acromegaly registries. Further experience exchange will facilitate the identification of specific strategies that can be adapted in each country, and widespread participation in acromegaly registries will enable their evaluation. It is anticipated that this approach will support the optimization of acromegaly patient care across this region.

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.

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.

Bone turnover, bone mineral density, and fracture risk in acromegaly: a meta-analysis

CONTEXT

GH excess causes an increase in bone turnover, but the consequences in terms of skeletal fragility have long been uncertain due to the heterogeneity of studies dealing with this topic.

OBJECTIVE

We conducted a meta-analysis of studies examining the effects of acromegaly on bone turnover, bone mineral density (BMD), and fractures. Furthermore, we evaluated the effects of sex, gonadal status, and activity of disease on skeletal end-points in acromegaly.

DATA SOURCES

We conducted MEDLINE and EMBASE systematic searches up to December 31, 2013.

STUDY ELIGIBILITY CRITERIA

Studies conducted in patients with acromegaly and reporting at least one determinant of skeletal fragility.

DATA EXTRACTION AND ANALYSIS

Study design, patient characteristics, interventions, and outcomes were independently extracted by two authors. We calculated the standardized mean difference (SMD) of bone turnover and BMD differences, whereas fractures were presented as relative frequencies in acromegaly and odds ratios between patients and controls.

RESULTS

Forty-one studies fulfilled eligibility criteria and were therefore selected for data extraction and analysis. A total of 1935 patients were included (eight to 206 per study). Acromegaly patients had higher bone formation (SMD, 1.49; 95% confidence interval [CI], 0.97-2.01; P < .0001) and bone resorption (SMD, 1.57; 95% CI, 1.03-2.10; P < .0001) as compared to control subjects, without significant differences in lumbar spine BMD. BMD at the femoral neck tended to be higher in acromegaly patients vs control subjects (SMD, 0.67; 95% CI, 0.07-1.27; P = .03). Patients with acromegaly had high frequency of vertebral fractures (odds ratio, 8.26; 95% CI, 2.91-23.39; P < .0001), in close relationship with male gender, hypogonadism, and active acromegaly.

LIMITATIONS

LIMITATIONS included heterogeneous study protocols with possible variability in the assessment of skeletal end-points.

CONCLUSIONS

Skeletal fragility is an emerging complication of acromegaly.