Bone Mineral Density Compared to Trabecular Bone Score in Primary Hyperparathyroidism

Natural history and complications of normocalcemic hyperparathyroidism: a retrospective cohort study

Normocalcemic hyperparathyroidism (NHPT) is variably defined, and information regarding complications and natural history are scarce. We aimed to describe the phenotype of NHPT in relation to hypercalcemic hyperparathyroidism (PHPT) and controls, to determine risk of progression, and to develop a predictive model for progression to PHPT. This is a retrospective chart review of 232 patients at a tertiary medical center, comparing 75 controls, 73 patients with NHPT, and 84 with PHPT. NHPT was intermediate in biochemical profile between controls and PHPT with respect to cCa, iPTH, intraindividual coefficient of variant of cCa, phosphorus, and 25(OH)D. NHPT patients had an increased adjusted risk of urolithiasis (OR 5.34, 95%CI, 2.41-12.71, P < .001) and fragility fractures (OR 4.53, 95%CI, 1.63-14.84, P = .006) versus controls, after adjustment for age, sex, and BMI. Fewer NHPT compared with PHPTH patients achieved cure with parathyroidectomy (P = .001). NHPT more often had nonlocalizing imaging or polyglandular disease (P = .005). Parathyroidectomy improved biochemical but not BMD parameters in NHPT. Over a median follow-up of 4.23 (IQR 1.76-5.31) years, NHPT patients managed expectantly experienced no change in iPTH, and progression to PHPT occurred in 9%. An XGBoost model combining 6 factors for progression (mean index 2 iPTH, mean index 2 cCa, 24-h urinary calcium, age, 25(OH)D, and presence of urolithiasis) had an area under the curve 1.00 (95%CI, 1.00-1.00, P < .001) for predicting combined progression. NHPT is a mild variant of PHPT at intermediate risk of urolithiasis and fragility fractures. Cure was less often achieved with parathyroidectomy, which did not improve BMD parameters. Progression was infrequent with conservative management. Because only a minority progressed to PHPT, in addition to lower surgical success rates, we suggest conservative management for the majority of NHPT unless risk factors for progression are identified.

Trabecular Bone Score as a More Sensitive Tool to Evaluate Bone Involvement in MEN1-related Primary Hyperparathyroidism

CONTEXT

The skeletal involvement of multiple endocrine neoplasia type 1-related primary hyperparathyroidism (MHPT) is not exactly the same as that of sporadic primary hyperparathyroidism (SHPT). Trabecular bone score (TBS) as a texture parameter has been reported to reflect trabecular bone damage.

OBJECTIVE

This study aimed to compare the clinical characteristics, especially the skeletal involvement, between patients with MHPT and SHPT.

METHODS

The clinical characteristics were retrospectively collected in 120 patients with MHPT and compared with 360 patients with SHPT in the same period. Dual-energy X-ray absorptiometry were conducted in some patients with MHPT, in whom bone mineral density (BMD) and calculated TBS derived from lumbar spine dual-energy X-ray absorptiometry images were compared with those of patients with SHPT.

RESULTS

Although the duration of disease in the MHPT group was longer, the age at hospital visit was significantly lower than that in the SHPT group (43.5 [interquartile range, 31.5-52.0] vs 52.0 [interquartile range, 40.5-61.0], P < .001). The proportion of skeletal involvement in the MHPT group was significantly lower. However, in the subgroup of MHPT cases (n = 86) with data of BMD, there was no significant difference in skeletal involvement from SHPT cases matched for gender and age. Although the BMD and TBS in the lumbar spines of patients with MHPT were lower than those of patients with SHPT (BMD: 0.91 ± 0.18 g/cm2 vs 1.01 ± 0.17 g/cm2; TBS: 1.22 ± 0.14 vs 1.29 ± 0.11, P < .001). According to TBS, among 34 patients with MHPT with normal BMD, 15 patients had bone microstructure damage.

CONCLUSION

The cancellous bone microarchitecture was more severely damaged in patients with MHPT according to TBS, which suggested that TBS could be a sensitive supplemental index in addition to BMD to identify bone-involvement risk in patients with MHPT.

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.

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.

Degraded Bone Microarchitecture in Women with PHPT-Significant Predictor of Fracture Probability

Introduction

Patients with primary hyperparathyroidism (PHPT) experience bone mineral density (BMD) loss and trabecular bone score (TBS) alteration, which current guidelines recommend assessing. Considering TBS alongside BMD for a 10-year fracture risk assessment (FRAX) may improve PHPT management.

Design

Retrospective, cross-sectional study composed of 49 Caucasian females (62 ± 10.6 years, 27.7 ± 0.87 kg/m²) with PHPT and 132 matched control subjects (61.3 ± 10.5 years, 27.5 ± 0.49 kg/m²) evaluated in 3 years. We assessed lumbar spine (LS) and femoral neck (FN) BMD, T and Z scores (GE Healthcare Lunar Osteodensitometer) and TBS (iNsight 1.8), major osteoporotic fracture (MOF), and hip FRAX.

Results

Patients with PHPT had statistically lower mean values for lumbar spine bone mineral density (LS BMD) (0.95 ± 0.25 vs 1.01 ± 0.14 g/cm², P = .01), LS T-scores (-2 ± 0.2 vs -1.4 ± 0.1 SD, P = .009), LS Z scores (-0.9 ± 0.19 vs -0.1 ± 0.11 SD, P = .009), femoral neck bone mineral density (FN BMD) (0.79 ± 0.02 vs 0.83 ± 0.01 g/cm², P = .02), FN T-scores (-1.8 ± 0.13 vs -1.5 ± 0.07 SD, P = .017), FN Z scores (-0.51 ± 0.87 vs -0.1 ± 0.82 SD, P = .006), and TBS (0.95 ± 0.25 vs 1.01 ± 0.14 g/cm², P = .01) compared with control subjects. 22.4% of patients with PHPT had degraded microarchitecture (TBS < 1.2) vs. 7.6% in control group (χ² = 0.008). PHPT proved to be a covariate with unique contribution (P = .031) alongside LS BMD (P = .040) in a linear regression model [R ² = 0.532, F(4,16) = 4.543] for TBS < 1.2. TBS adjustment elevated MOF FRAX both for PHPT (4.35  ± 0.6% vs 5.25% ± 0.73%, P < .001) and control groups (4.5  ± 0.24% vs 4.7% ± 0.26%, P < .001) compared with BMD-bases FRAX, but also increased differently between the 2 study groups (1.1-folds for PHPT patients and 1.04 for control subjects, P = .034).

Conclusion

Compared with control, TBS-adjusted FRAX provides significantly higher MOF risk than BMD-based FRAX in PHPT women.