Clinical Utility of Using Lumbar Spine Trabecular Bone Score to Adjust Fracture Probability: The Manitoba BMD Cohort

Bone microstructure and TBS in diabetes: what have we learned? A narrative review

Diabetes is associated with an increased risk of fracture. Areal bone mineral density (aBMD), the most reliable indicator of fracture risk in healthy adults, is low in patients with type 1 diabetes mellitus but normal or high in patients with type 2 diabetes mellitus. Most trabecular and cortical parameters measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) are lower in type 1 diabetes and higher in type 2 diabetes, in parallel with aBMD. In contrast, lumbar spine trabecular bone score (TBS) has been reported to be lower in women with both type 1 and type 2 diabetes. The discordance between improved bone microstructure and degraded TBS reflects the effect of central obesity (currently the subject of a revision to the TBS algorithm). Meanwhile, evidence supports use of TBS in conjunction with aBMD and/or FRAX for improved fracture prediction in patients with type T2D. This position paper, on behalf of the Bone and Diabetes Working Group of the International Osteoporosis Foundation, summarizes alterations in bone microarchitecture measured by HR-pQCT in diabetes. It also addresses the technical and clinical considerations of the trabecular bone score, particularly discussing the significance of this measurement in individuals with diabetes and the influence of abdominal fat.

Accuracy of artificial intelligence in prediction of osteoporotic fractures in comparison with dual-energy X-ray absorptiometry and the Fracture Risk Assessment Tool: A systematic review

BACKGROUND

Osteoporotic fractures, whether due to postmenopausal or senile causes, impose a significant financial burden on developing countries and diminish quality of life. Recent advancements in artificial intelligence (AI) algorithms have demonstrated immense potential in predicting osteoporotic fractures.

AIM

To assess and compare the efficacy of AI models against dual-energy X-ray absorptiometry (DXA) and the Fracture Risk Assessment Tool (FRAX) in predicting fragility fractures.

METHODS

We conducted a literature search in English using electronic databases, including PubMed, Web of Science, and Scopus, for studies published until May 2024. The keywords employed were fragility fractures, osteoporosis, AI, deep learning, machine learning, and convolutional neural network. The inclusion criteria for selecting publications were based on studies involving patients with proximal femur and vertebral column fractures due to osteoporosis, utilizing AI algorithms, and analyzing the site of fracture and accuracy for predicting fracture risk using SPSS version 29 (Chicago, IL, United States).

RESULTS

We identified 156 publications for analysis. After applying our inclusion criteria, 24489 patients were analyzed from 13 studies. The mean area under the receiver operating characteristic curve was 0.925 ± 0.69. The mean sensitivity was 68.3% ± 15.3%, specificity was 85.5% ± 13.4%, and positive predictive value was 86.5% ± 6.3%. DXA showed a sensitivity of 37.0% and 74.0%, while FRAX demonstrated a sensitivity of 45.7% and 84.7%. The P value for sensitivity between DXA and AI was < 0.0001, while for FRAX it was < 0.0001 and 0.2.

CONCLUSION

This review found that AI is a valuable tool to analyze and identify patients who will suffer from fragility fractures before they occur, demonstrating superiority over DXA and FRAX. Further studies are necessary to be conducted across various centers with diverse population groups, larger datasets, and a longer duration of follow-up to enhance the predictive performance of the AI models before their universal application.

TBS as a complementary tool for assessing vertebral fractures and spinal deformity in children and adolescents with osteogenesis imperfecta

This study evaluated trabecular bone score (TBS) for assessing vertebral fractures and spinal deformity in children and adolescents with osteogenesis imperfecta (OI). TBS showed superior performance in identifying vertebral fractures compared to areal bone mineral density (aBMD), especially in patients without densitometric osteoporosis, suggesting its potential for monitoring vertebral fractures and spinal deformity risk.

BACKGROUND

TBS, derived from a textural greyscale analysis of lumbar spine dual-energy X-ray absorptiometry (DXA) images, offers a non-invasive and indirect evaluation of bone microarchitecture. This method potentially enhances the assessment of skeletal phenotypes beyond the scope of aBMD. We aim to explore the utility of TBS in assessing vertebral fractures and spinal deformity in children and adolescents with OI.

METHODS

In this cross-sectional study, 153 children and adolescents with OI were enrolled. DXA was used to measure TBS and aBMD, and their Z-scores were calculated based on reference values for BMD and TBS in normal children and adolescents with the same age and sex. Lateral thoracolumbar films were used to evaluate vertebral fractures and calculate the spine deformity index (SDI). The accuracy of TBS and aBMD for identifying vertebral compression fractures (VCFs) was assessed using area under the curve (AUC).

RESULTS

TBS Z-score was negatively correlated with the age of children with OI (r =  - 0.435, P < 0.001) and was positively correlated to aBMD Z-score at the lumbar spine and femoral neck (both P < 0.01), even after adjusting for confounding factors. TBS Z-score was as effective as lumbar spine aBMD Z-score in discriminating VCFs (AUC, 0.667 vs 0.666, P > 0.05). Notably, in patients without densitometric osteoporosis, TBS Z-score demonstrated superior discriminative power for VCFs compared to lumbar spine aBMD Z-score (AUC, 0.719 vs 0.545, P < 0.05). In this population, only the TBS Z-score (r =  - 0.358, P < 0.05), rather than the lumbar spine aBMD Z-score, was negatively correlated with the SDI.

CONCLUSION

TBS has a close correlation with bone mineral density in children and adolescents with OI. In patients without densitometric osteoporosis, the Z-score of TBS is more effective than that of bone mineral density in assessing VCFs and spinal deformity, highlighting the potential of TBS in evaluating the risk of VCFs and monitoring the progression of spinal deformity.

Bone health and bisphosphonate treatment in females with Rett syndrome in a national center

BACKGROUND

Impaired bone health is a common morbidity in Rett syndrome (RTT). We aimed to assess lumbar bone mineral density (BMD) and trabecular bone score (TBS) in females with RTT, and to evaluate the effectiveness of bisphosphonate treatment.

METHODS

This retrospective study included 40 females with RTT, aged 5-22 years, who underwent dual-energy X-ray absorptiometry (DXA) scans during 2019-2024 at a national center for RTT. Data collected included medical treatment, anthropometric measurements, and functional scores.

RESULTS

The median age at the first DXA scan was 10.8 years. The mean L1-4 BMD Z-score was -2.1 ± 1.4, and the mean TBS Z-score was -0.4 ± 1.3. The L1-4 BMD Z-score correlated with height (r = 0.407, p = 0.009), weight (r = 0.551, p < 0.001), BMI (r = 0.644, p < 0.001), and TBS Z-scores (r = 0.594, p = 0.009). Poor L1-4 BMD Z-scores were associated with poor mobility scores (p = 0.05) and valproate treatment (p = 0.016). Nine patients (23%) received zoledronate, for a mean 2 years. The mean age at zoledronate initiation was 9.7 ± 2.3 years. Four completed two DXA scans (pre- and post-treatment); the mean BMD Z-score improved from -2.2 ± 0.9 to -1.4 ± 0.9 after treatment.

CONCLUSIONS

Females with RTT have reduced lumbar BMD, which was associated with anthropometric factors, TBS, mobility, and valproate use. Zoledronate may be effective for some patients.

IMPACT

In a retrospective study of 40 females with Rett syndrome (RTT), low bone mineral density (BMD) correlated with lower anthropometric measurements, impaired mobility, and valproic acid use. The association between BMD and trabecular bone score (TBS) in the context of RTT is a novel finding. Our preliminary data support the effectiveness and safety of zoledronate for treating osteoporosis in patients with RTT. Our findings are important in light of the increasing life expectancy of individuals with RTT, and the consequent need to prioritize bone health in this population.

Canadian Adult Reference Data for Body Composition, Trabecular Bone Score and Advanced Hip Analysis Using DXA

DXA-derived reference data for visceral adipose tissue (VAT) and advanced hip analysis (AHA) parameters spanning the entire adult lifespan are limited. The purpose of this study was to develop age-, site- and sex-specific reference data for dual X-ray absorptiometry (DXA) -derived body composition, trabecular bone score (TBS) and advanced hip analysis (AHA) parameters across the adult lifespan. Adults (N = 908; female: 561 and male: 347) from Calgary and the surrounding area over the age of 20 years participated in this study. Participants received DXA scans of their hip (total hip [TH] and femoral neck [FN]), lumbar spine [LS], forearm [33 % site] and total body (iDXA, GE Lunar, GE Healthcare). Areal bone mineral density (aBMD, g/cm2) was captured at all sites, and body composition variables, including lean mass, fat mass and percent fat, were analyzed from the total body scan. VAT mass was assessed from total body DXA scans. Advanced hip analysis (AHA) was performed on hip scans and trabecular bone score (TBS) on the LS scans to assess bone quality. Site- and sex-specific centile curves and tables were generated using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method. Clinicians and researchers can use these Canadian reference data as a tool to assess body composition, TBS and AHA parameters across the adult lifespan.

Assessment of fracture risk in diabetic patients

Patients with diabetes often experience reduced bone strength, resulting in a higher fracture risk. This decline and increased susceptibility stem from intricate interactions within the bone microstructure. However, current gold standard methods for assessing bone strength, such as bone mineral density, and widely-used fracture risk assessment tools do not accurately predict fracture risk in diabetic patients. Therefore, it is crucial to incorporate additional indicators that evaluate bone quality and specific markers relevant to diabetes to enhance the accuracy of predictive models. Moreover, the selection of appropriate algorithms for model construction is essential. This review aims to introduce indicators from both imaging examinations and laboratory indicators that hold significant value for inclusion in fracture risk prediction models for diabetic patients. Additionally, this study provides an overview of the research progress in fracture risk prediction models for diabetic patients, serving as a valuable reference for clinical practice.

Predictors of lumbar spine trabecular bone score in women with postsurgical hypoparathyroidism

Hypoparathyroidism is a rare disease that markedly reduces bone remodeling, leading to increased bone mineral density and changes in bone microarchitecture. However, it is currently unclear how these changes affect fracture risk. In this study, we investigated bone mass by dual-energy x-ray absorptiometry, the occurrence of morphometric vertebral fractures, and bone microarchitecture by assessing trabecular bone score in women with postsurgical hypoparathyroidism. We included 67 women with hypoparathyroidism aged 52.9 ± 12.3 years and 63 age- and body mass index-matched controls, which were assessed for femoral and lumbar spine bone mineral density, trabecular bone score, and vertebral fractures by dual-energy x-ray absorptiometry. Women with hypoparathyroidism had significantly higher bone mineral density at the lumbar spine, femoral neck, and total hip compared with controls despite similar trabecular bone score values. Vertebral fracture assessment indicated that two women with hypoparathyroidism presented vertebral fractures, both aged over 65 years. Conversely, no vertebral fractures were detected in control women. In a multivariate linear regression model, we found that older age, diabetes, and lower lumbar spine mineral density were significant predictors of lower trabecular bone score values. Our findings indicate that vertebral fractures are not common among women with postsurgical hypoparathyroidism aged under 65 years. Moreover, trabecular bone score values were similar in women with hypoparathyroidism and age-matched controls and were associated with traditional risk factors for fractures, such as older age, type 2 diabetes, and lower spine bone mineral density. LAY SUMMARY: Chronic parathyroid hormone deficiency decreases bone turnover and modifies skeletal properties, although the impact of these changes on fracture risk remains unclear. We studied 67 women with postsurgical hypoparathyroidism and 63 age and body mass index-matched healthy controls and found that bone mineral density is increased in women with hypoparathyroidism despite similar trabecular bone score values and a low occurrence of morphometric vertebral fractures. This suggests that the low bone turnover in hypoparathyroidism increases bone mass, but this is not accompanied by improved bone microarchitecture, indicating that trabecular bone score may be a valuable tool to complement the assessment of skeletal health and the risk of fractures in this condition.

Unraveling the relationship between serum parathyroid hormone levels and trabecular bone score: a cross-sectional study

The TBS is a new method for clinicians to assess the bone quality. It is directly related to the mechanical strength of bone and helps predict fracture risk. The present analysis aimed to investigate the associations between serum PTH levels and TBS by analyzing data from the National Health and Nutrition Examination Survey (NHANES). A total of 3516 participants from the NHANES 2005-2006 were included in this cross-sectional study. The independent variable was serum PTH, and the outcome variable was TBS. The associations of serum PTH levels with TBS were examined using multivariable linear regression models. After adjusting for covariates, there was a negative association between serum PTH level and TBS (β = - 0.0034; 95% confidence interval, - 0.0050 to - 0.0017). However, in the subgroup analysis stratified by gender, race, and age, this association became negative only in Non-Hispanic White (β =  - 0.0047, 95% CI:  -  0.0071 to  -  0.0048) and young people (age < 60) (β = - 0.0036, 95% CI: - 0.0057, - 0.0016), regardless of gender. In addition, the association of serum PTH with TBS was an U-shaped curve, with a point of inflection at 6.71 pmol/L. This study showed that serum PTH level was negatively associated with TBS. Maintaining PTH levels in a lower reasonable clinical range may be beneficial to bone health, especially for young non-Hispanic white.

Predictive factors of osteoporotic hip fracture in octogenarians

OBJECTIVE

This study aims to identify the risk factors associated with osteoporotic hip fractures in octogenarians and seeks to refine primary prevention strategies for these fractures.

MATERIAL AND METHODS

We conducted a case-control study involving individuals aged 79 years and older with hip fractures, comparing them to age- and sex-matched controls without a history of hip fractures. We collected epidemiological, clinical, anthropometric, and analytical factors. We evaluated the presence of osteoporosis using bone densitometry. We defined sarcopenia according the European Working Group on Sarcopenia in Older People criteria (EWGSOP2).

RESULTS

Ninety-five patients per group were analyzed, with a mean age of 82 years, of which 74% were women. The multivariate analysis included statistically significant factors found in the univariate analysis (p < 0.05). These factors included the Barthel Index, nutritional assessment using the CONUT tool, folic acid, vitamin D deficiency, presence of previous fractures, loss of visual acuity, bicipital circumference, sarcopenia, and osteoporosis (densitometry in the neck of the femur). The Nutritional state (OR: 0.08 [0.01-0.61]), the folic acid levels (OR 0.32 [0.1-1]), and a loss of visual acuity (OR 33.16 [2.91-377.87]) were the independent risk factors associated with hip fracture.

CONCLUSIONS

The assessment of nutritional status in elderly patients, coupled with a comprehensive geriatric assessment, represents easily reproducible and cost-effective tools. These tools can effectively aid in identifying individuals at risk of hip fractures, thereby contributing to more targeted and efficient preventive measures.

Clinical Use of Trabecular Bone Score: The 2023 ISCD Official Positions

Osteoporosis can currently be diagnosed by applying the WHO classification to bone mineral density (BMD) assessed by dual-energy x-ray absorptiometry (DXA). However, skeletal factors other than BMD contribute to bone strength and fracture risk. Lumbar spine TBS, a grey-level texture measure which is derived from DXA images has been extensively studied, enhances fracture prediction independent of BMD and can be used to adjust fracture probability from FRAX® to improve risk stratification. The purpose of this International Society for Clinical Densitometry task force was to review the existing evidence and develop recommendations to assist clinicians regarding when and how to perform, report and utilize TBS. Our review concluded that TBS is most likely to alter clinical management in patients aged ≥ 40 years who are close to the pharmacologic intervention threshold by FRAX. The TBS value from L1-L4 vertebral levels, without vertebral exclusions, should be used to calculate adjusted FRAX probabilities. L1-L4 vertebral levels can be used in the presence of degenerative changes and lumbar compression fractures. It is recommended not to report TBS if extreme structural or pathological artifacts are present. Monitoring and reporting TBS change is unlikely to be helpful with the current version of the TBS algorithm. The next version of TBS software will include an adjustment based upon directly measured tissue thickness. This is expected to improve performance and address some of the technical factors that affect the current algorithm which may require modifications to these Official Positions as experience is acquired with this new algorithm.

Cross-sectional analysis of the correlation between serum uric acid and trabecular bone score: NHANES 2005-2008

Serum uric acid (SUA) has been discovered to be associated with bone mineral density (BMD), but its relationship with trabecular bone score (TBS) remains unclear. Thus, the aim of our study was to investigate the association between SUA levels and TBS. Our study included 5895 individuals over 20 years old (3061 men and 2834 women) from NHANES 2005-2008. To analyze the association between SUA and TBS, multivariate linear regression models with covariate adjustments were applied. Furthermore, population description, stratified analysis, single factor analysis, smooth curve fitting, interaction analysis, and threshold effect and saturation effect analysis were also conducted. After adjusting for covariates, SUA showed a strong negative relationship with total TBS (β = 0.319; 95% CI 0.145-0.494; P < 0.001). The relationship between SUA levels and total TBS was found to be nonlinear, with inflection points at 4.8 mg/dL for the overall population, 4.2 mg/dL for women, and 5.7 mg/dL for non-Hispanic whites, indicating a saturation effect. Additionally, no interactions were found in any of the subgroups. Our study found a negative association between SUA and total TBS in adults. Maintaining SUA at a saturated level can benefit in preventing osteoporosis and fractures.

Adjusting Trabecular Bone Score (TBS) for Level-Specific Differences Reduces FRAX®-Based Treatment Reclassification in Patients with Vertebral Exclusions: The Manitoba BMD Registry

Trabecular bone score (TBS) is a FRAX®-independent risk factor for fracture prediction. TBS values increase from cranial to caudal, with the following mean differences between TBSL1-L4 and individual lumbar vertebrae: L1 -0.093, L2 -0.008, L3 +0.055 and L4 +0.046. Excluding vertebral levels can affect FRAX-based treatment recommendations close to the intervention threshold. We examined the effect of adjusting for level-specific TBS differences in individuals with vertebral exclusions due to structural artifact on TBS-adjusted FRAX-based treatment recommendations. We identified 71,209 individuals aged ≥40 years with TBS and FRAX calculations through the Manitoba Bone Density Program. In the 24,428 individuals with vertebral exclusions, adjusting TBS using these level-specific factors agreed with TBSL1-L4 (mean difference -0.001). We compared FRAX-based treatment recommendations for TBSL1-L4 and for non-excluded vertebral levels before and after adjusting for level-specific TBS differences. Among those with baseline major osteoporotic fracture risk ≥15 %, TBS with vertebral exclusions reclassified FRAX-based treatment in 10.6 % of individuals compared with TBSL1-L4, and was reduced to 7.2 % after adjusting for level-specific differences. In 11,131 patients where L1-L2 was used for BMD reporting (the most common exclusion pattern with the largest TBS effect), treatment reclassification was reduced from 13.9 % to 2.4 %, respectively. Among individuals with baseline hip fracture risk ≥2 %, TBS vertebral exclusions reclassified 7.1 % compared with TBSL1-L4, but only 4.5 % after adjusting for level-specific differences. When L1-L2 was used for BMD reporting, treatment reclassification from hip fracture risk was reduced from 9.2 % to 5.2 %. In conclusion, TBS and TBS-adjusted FRAX-based treatment recommendations are affected by vertebral level exclusions for structural artifact. Adjusting for level-specific differences in TBS reduces reclassification in FRAX-based treatment recommendations.

Proceedings of the 2023 Santa Fe Bone Symposium: Progress and Controversies in the Management of Patients with Skeletal Diseases

The Santa Fe Bone Symposium (SFBS) held its 23rd annual event on August 5-6, 2023, in Santa Fe, New Mexico, USA. Attendees participated in-person and remotely, representing many states and countries. The program included plenary presentations, panel discussions, satellite symposia, a Project ECHO workshop, and a session on healthcare policy and reimbursement for fracture liaison programs. A broad range of topics were addressed, including transitions of osteoporosis treatments over a lifetime; controversies in vitamin D; update on Official Positions of the International Society for Clinical Densitometry; spine surgery and bone health; clinical applications of bone turnover markers; basic bone biology for clinicians; premenopausal-, pregnancy-, and lactation-associated osteoporosis; cancer treatment induced bone loss in patients with breast cancer and prostate cancer; genetic testing for skeletal diseases; and an update on nutrition and bone health. There were also sessions on rare bone diseases, including managing patients with hypophosphatasia; treatment of X-linked hypophosphatemia; and assessment and treatment of patients with hypoparathyroidism. There were oral presentations of abstracts by endocrinology fellows selected from those who participated in the Santa Fe Fellows Workshop on Metabolic Bone Diseases, held the 2 days prior to the SFBS. These proceedings of the 2023 SFBS present the clinical highlights and insights generated from many formal and informal discussions in Santa Fe.

FRAX® Adjustment Using Renormalized Trabecular Bone Score (TBS) from L1 Alone may be Optimal for Fracture Prediction: The Manitoba BMD Registry

Lumbar spine trabecular bone score (TBS) used in conjunction with FRAX® improves 10-year fracture prediction. The derived FRAX risk adjustment is based upon TBS measured from L1-L4, designated TBSL1-L4-FRAX. In prior studies, TBS measurements that include L1 and exclude L4 give better fracture stratification than L1-L4. We compared risk stratification from TBS-adjusted FRAX using TBS derived from different combinations of upper lumbar vertebral levels renormalized for level-specific differences in individuals from the Manitoba Bone Density Program aged >40 years with baseline assessment of TBS and FRAX. TBS measurements for L1-L3, L1-L2 and L1 alone were calculated after renormalization for level-specific differences. Corresponding TBS-adjusted FRAX scores designated TBSL1-L3-FRAX, TBSL1-L2-FRAX and TBSL1-FRAX were compared with TBSL1-L4-FRAX for fracture risk stratification. Incident major osteoporotic fractures (MOF) and hip fractures were assessed. The primary outcome was incremental change in area under the curve (ΔAUC). The study population included 71,209 individuals (mean age 64 years, 89.8% female). Before renormalization, mean TBS for L1-3, L1-L2 and L1 was significantly lower and TBS-adjusted FRAX significantly higher than from using TBSL1-L4. These differences were largely eliminated when TBS was renormalized for level-specific differences. During mean follow-up of 8.7 years 6745 individuals sustained incident MOF and 2039 sustained incident hip fractures. Compared with TBSL1-L4-FRAX, use of FRAX without TBS was associated with lower stratification (ΔAUC = -0.009, p < 0.001). There was progressive improvement in MOF stratification using TBSL1-L3-FRAX (ΔAUC = +0.001, p < 0.001), TBSL1-L2-FRAX (ΔAUC = +0.004, p < 0.001) and TBSL1-FRAX (ΔAUC = +0.005, p < 0.001). TBSL1-FRAX was significantly better than all other combinations for MOF prediction (p < 0.001). Incremental improvement in AUC for hip fracture prediction showed a similar but smaller trend. In conclusion, this single large cohort study found that TBS-adjusted FRAX performance for fracture prediction was improved when limited to the upper lumbar vertebral levels and was best using L1 alone.

Urinary pentosidine level is associated with the risk of fracture in community-dwelling older adults: a prospective observational study

A history of fracture in adulthood and urinary pentosidine levels were independently and significantly associated with fracture occurrence in this prospective observational study of community-dwelling older adults.

PURPOSE

This prospective observational study aimed to determine the factors associated with fragility fractures in community-dwelling older adults.

METHODS

Overall, 254 older adults who were participants of the Good Aging and Intervention Against Nursing Care and Activity Decline study in 2016 were included in this study. Grip strength, muscle mass, gait speed, calcaneal bone density, and the levels of parathyroid hormone, osteocalcin, 25-hydroxyvitamin D, total procollagen type I N-terminal propeptide, insulin-like growth factor-1 (IGF-1), tartrate-resistant acid phosphatase-5b, and urinary pentosidine were measured at baseline. Participants were classified as fracture ( +) or fracture (-) based on the data collected during a 5-year follow-up period.

RESULTS

Excluding those who were lost to follow-up during the observation period, 182 participants (64 men and 118 women, mean age: 74.2 years, range: 47-99 years) were included in the analysis. During the observation period, 23 patients experienced 24 new fractures. In univariate analysis, sex, height, weight, history of fracture in adulthood, baseline grip strength, muscle mass, bone density, and the levels of urinary pentosidine and IGF-1 at baseline were significantly different between patients who developed a fracture during follow-up and those who did not. In multivariate analysis, a history of fracture in adulthood and urinary pentosidine levels were independently and significantly associated with fracture occurrence.

CONCLUSION

High urine pentosidine levels and a history of fracture in adulthood are independent risk factors for fracture occurrence in community-dwelling older adults.

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.

Trabecular Bone Score Vertebral Exclusions Affect Risk Classification and Treatment Recommendations: The Manitoba Bmd Registry

Lumbar spine trabecular bone score (TBS), a texture measure derived from spine dual-energy x-ray absorptiometry (DXA) images, is a bone mineral density (BMD)-independent risk factor for fracture. Lumbar vertebral levels that show structural artifact are excluded from BMD measurement. TBS is relatively unaffected by degenerative artifact, and it is uncertain whether the same exclusions should be applied to TBS reporting. To gain insight into the clinical impact of vertebral exclusion on TBS, we examined the effect of lumbar vertebral exclusions in routine clinical practice on tertile-based TBS categorization and TBS adjusted FRAX-based treatment recommendations. The study population consisted of 71,209 individuals aged 40 years and older with narrow fan-beam spine DXA examinations and retrospectively-derived TBS. During BMD reporting, 34.3% of the scans had one or more vertebral exclusions for structural artifact. When TBS was derived from the same vertebral levels used for BMD reporting, using fixed L1-L4 tertile cutoffs (1.23 and 1.31 from the McCloskey meta-analysis) reclassified 17.9% to a lower and 6.5% to a higher TBS category, with 75.6% unchanged. Reclassification was reduced from 24.4% overall to 17.2% when level-specific tertile cutoffs from the software manufacturer were used. Treatment reclassification based upon FRAX major osteoporotic fracture probability occurred in 2.9% overall, but in 9.6% of those with baseline risk ≥15%. For treatment based upon FRAX hip fracture probability, reclassification occurred in 3.4% overall, but in 10.4% in those with baseline risk ≥2%. In summary, lumbar spine TBS measurements based upon vertebral levels other than L1-L4 can alter the tertile category and treatment recommendations based upon TBS-adjusted FRAX calculation, especially for those close to or exceeding the treatment cut-off. Manufacturer level-specific tertile cut-offs should be used if vertebral exclusions are applied.

Osteoporosis: Review of Etiology, Mechanisms, and Approach to Management in the Aging Population

Osteoporosis is the most common metabolic bone disease. With special respect to the aging population, it is very common, not only due to changes in lifestyle and diet but as a result of the aging process there is low-grade inflammation and immune system activation that directly affects bone strength and quality. This article provides a review of the incidence, etiology, and approach to screening and management of osteoporosis in the aging population. A thorough screening of lifestyle, environmental, and clinical conditions will be reviewed which identifies appropriate candidates for screening and treatment.

Fracture risk gradient assessed by categories of bone mineral density and trabecular bone score: the Manitoba BMD Registry

Trabecular bonescore (TBS) helps to predict fracture risk in older adults. In this registry-based cohort study of patients aged 40 years and older, reduction in bone mineral density (BMD) and TBS are complementary for fracture risk prediction enhancement with lower BMD imparting greater risk than reduction in TBS.

PURPOSE

Trabecular bone score (TBS) enhances fracture risk prediction independent of bone mineral density (BMD) in older adults. The purpose of this study was to further evaluate the gradient of fracture risk based on TBS tertile categories and WHO BMD categories, adjusted for other risk factors.

METHODS

Using the Manitoba DXA registry, patients aged 40 years and older with spine/hip DXA and L1-L4 TBS were identified. Any incident fractures, major osteoporotic fractures (MOF), and hip fractures were identified. Cox regression models were used to estimate unadjusted and covariate-adjusted hazard ratios (HR, 95%CI) for incident fracture by BMD and TBS category and for each SD decrease in BMD and TBS.

RESULTS

The study population included 73,108 individuals, 90% female with mean age 64 years. Mean (SD) minimum T-score was - 1.8 (1.1), and mean L1-L4 TBS was 1.257 (0.123). Lower BMD and TBS, both per SD, by WHO BMD category and by TBS tertile category, were significantly associated with MOF, hip, and any fracture (all HRs p < 0.001). However, the quantum of risk was consistently greater for BMD than TBS, with HRs showing non-overlapping CIs.

CONCLUSION

TBS is complementary to BMD in prediction of incident major, hip, and any osteoporosis-related fracture, but reductions in BMD impart greater risk than reductions in TBS on both continuous and categorical scales.

Screening for the primary prevention of fragility fractures among adults aged 40 years and older in primary care: systematic reviews of the effects and acceptability of screening and treatment, and the accuracy of risk prediction tools

BACKGROUND

To inform recommendations by the Canadian Task Force on Preventive Health Care, we reviewed evidence on the benefits, harms, and acceptability of screening and treatment, and on the accuracy of risk prediction tools for the primary prevention of fragility fractures among adults aged 40 years and older in primary care.

METHODS

For screening effectiveness, accuracy of risk prediction tools, and treatment benefits, our search methods involved integrating studies published up to 2016 from an existing systematic review. Then, to locate more recent studies and any evidence relating to acceptability and treatment harms, we searched online databases (2016 to April 4, 2022 [screening] or to June 1, 2021 [predictive accuracy]; 1995 to June 1, 2021, for acceptability; 2016 to March 2, 2020, for treatment benefits; 2015 to June 24, 2020, for treatment harms), trial registries and gray literature, and hand-searched reviews, guidelines, and the included studies. Two reviewers selected studies, extracted results, and appraised risk of bias, with disagreements resolved by consensus or a third reviewer. The overview of reviews on treatment harms relied on one reviewer, with verification of data by another reviewer to correct errors and omissions. When appropriate, study results were pooled using random effects meta-analysis; otherwise, findings were described narratively. Evidence certainty was rated according to the GRADE approach.

RESULTS

We included 4 randomized controlled trials (RCTs) and 1 controlled clinical trial (CCT) for the benefits and harms of screening, 1 RCT for comparative benefits and harms of different screening strategies, 32 validation cohort studies for the calibration of risk prediction tools (26 of these reporting on the Fracture Risk Assessment Tool without [i.e., clinical FRAX], or with the inclusion of bone mineral density (BMD) results [i.e., FRAX + BMD]), 27 RCTs for the benefits of treatment, 10 systematic reviews for the harms of treatment, and 12 studies for the acceptability of screening or initiating treatment. In females aged 65 years and older who are willing to independently complete a mailed fracture risk questionnaire (referred to as "selected population"), 2-step screening using a risk assessment tool with or without measurement of BMD probably (moderate certainty) reduces the risk of hip fractures (3 RCTs and 1 CCT, n = 43,736, absolute risk reduction [ARD] = 6.2 fewer in 1000, 95% CI 9.0-2.8 fewer, number needed to screen [NNS] = 161) and clinical fragility fractures (3 RCTs, n = 42,009, ARD = 5.9 fewer in 1000, 95% CI 10.9-0.8 fewer, NNS = 169). It probably does not reduce all-cause mortality (2 RCTs and 1 CCT, n = 26,511, ARD = no difference in 1000, 95% CI 7.1 fewer to 5.3 more) and may (low certainty) not affect health-related quality of life. Benefits for fracture outcomes were not replicated in an offer-to-screen population where the rate of response to mailed screening questionnaires was low. For females aged 68-80 years, population screening may not reduce the risk of hip fractures (1 RCT, n = 34,229, ARD = 0.3 fewer in 1000, 95% CI 4.2 fewer to 3.9 more) or clinical fragility fractures (1 RCT, n = 34,229, ARD = 1.0 fewer in 1000, 95% CI 8.0 fewer to 6.0 more) over 5 years of follow-up. The evidence for serious adverse events among all patients and for all outcomes among males and younger females (<65 years) is very uncertain. We defined overdiagnosis as the identification of high risk in individuals who, if not screened, would never have known that they were at risk and would never have experienced a fragility fracture. This was not directly reported in any of the trials. Estimates using data available in the trials suggest that among "selected" females offered screening, 12% of those meeting age-specific treatment thresholds based on clinical FRAX 10-year hip fracture risk, and 19% of those meeting thresholds based on clinical FRAX 10-year major osteoporotic fracture risk, may be overdiagnosed as being at high risk of fracture. Of those identified as being at high clinical FRAX 10-year hip fracture risk and who were referred for BMD assessment, 24% may be overdiagnosed. One RCT (n = 9268) provided evidence comparing 1-step to 2-step screening among postmenopausal females, but the evidence from this trial was very uncertain. For the calibration of risk prediction tools, evidence from three Canadian studies (n = 67,611) without serious risk of bias concerns indicates that clinical FRAX-Canada may be well calibrated for the 10-year prediction of hip fractures (observed-to-expected fracture ratio [O:E] = 1.13, 95% CI 0.74-1.72, I2 = 89.2%), and is probably well calibrated for the 10-year prediction of clinical fragility fractures (O:E = 1.10, 95% CI 1.01-1.20, I2 = 50.4%), both leading to some underestimation of the observed risk. Data from these same studies (n = 61,156) showed that FRAX-Canada with BMD may perform poorly to estimate 10-year hip fracture risk (O:E = 1.31, 95% CI 0.91-2.13, I2 = 92.7%), but is probably well calibrated for the 10-year prediction of clinical fragility fractures, with some underestimation of the observed risk (O:E 1.16, 95% CI 1.12-1.20, I2 = 0%). The Canadian Association of Radiologists and Osteoporosis Canada Risk Assessment (CAROC) tool may be well calibrated to predict a category of risk for 10-year clinical fractures (low, moderate, or high risk; 1 study, n = 34,060). The evidence for most other tools was limited, or in the case of FRAX tools calibrated for countries other than Canada, very uncertain due to serious risk of bias concerns and large inconsistency in findings across studies. Postmenopausal females in a primary prevention population defined as <50% prevalence of prior fragility fracture (median 16.9%, range 0 to 48% when reported in the trials) and at risk of fragility fracture, treatment with bisphosphonates as a class (median 2 years, range 1-6 years) probably reduces the risk of clinical fragility fractures (19 RCTs, n = 22,482, ARD = 11.1 fewer in 1000, 95% CI 15.0-6.6 fewer, [number needed to treat for an additional beneficial outcome] NNT = 90), and may reduce the risk of hip fractures (14 RCTs, n = 21,038, ARD = 2.9 fewer in 1000, 95% CI 4.6-0.9 fewer, NNT = 345) and clinical vertebral fractures (11 RCTs, n = 8921, ARD = 10.0 fewer in 1000, 95% CI 14.0-3.9 fewer, NNT = 100); it may not reduce all-cause mortality. There is low certainty evidence of little-to-no reduction in hip fractures with any individual bisphosphonate, but all provided evidence of decreased risk of clinical fragility fractures (moderate certainty for alendronate [NNT=68] and zoledronic acid [NNT=50], low certainty for risedronate [NNT=128]) among postmenopausal females. Evidence for an impact on risk of clinical vertebral fractures is very uncertain for alendronate and risedronate; zoledronic acid may reduce the risk of this outcome (4 RCTs, n = 2367, ARD = 18.7 fewer in 1000, 95% CI 25.6-6.6 fewer, NNT = 54) for postmenopausal females. Denosumab probably reduces the risk of clinical fragility fractures (6 RCTs, n = 9473, ARD = 9.1 fewer in 1000, 95% CI 12.1-5.6 fewer, NNT = 110) and clinical vertebral fractures (4 RCTs, n = 8639, ARD = 16.0 fewer in 1000, 95% CI 18.6-12.1 fewer, NNT=62), but may make little-to-no difference in the risk of hip fractures among postmenopausal females. Denosumab probably makes little-to-no difference in the risk of all-cause mortality or health-related quality of life among postmenopausal females. Evidence in males is limited to two trials (1 zoledronic acid, 1 denosumab); in this population, zoledronic acid may make little-to-no difference in the risk of hip or clinical fragility fractures, and evidence for all-cause mortality is very uncertain. The evidence for treatment with denosumab in males is very uncertain for all fracture outcomes (hip, clinical fragility, clinical vertebral) and all-cause mortality. There is moderate certainty evidence that treatment causes a small number of patients to experience a non-serious adverse event, notably non-serious gastrointestinal events (e.g., abdominal pain, reflux) with alendronate (50 RCTs, n = 22,549, ARD = 16.3 more in 1000, 95% CI 2.4-31.3 more, [number needed to treat for an additional harmful outcome] NNH = 61) but not with risedronate; influenza-like symptoms with zoledronic acid (5 RCTs, n = 10,695, ARD = 142.5 more in 1000, 95% CI 105.5-188.5 more, NNH = 7); and non-serious gastrointestinal adverse events (3 RCTs, n = 8454, ARD = 64.5 more in 1000, 95% CI 26.4-13.3 more, NNH = 16), dermatologic adverse events (3 RCTs, n = 8454, ARD = 15.6 more in 1000, 95% CI 7.6-27.0 more, NNH = 64), and infections (any severity; 4 RCTs, n = 8691, ARD = 1.8 more in 1000, 95% CI 0.1-4.0 more, NNH = 556) with denosumab. For serious adverse events overall and specific to stroke and myocardial infarction, treatment with bisphosphonates probably makes little-to-no difference; evidence for other specific serious harms was less certain or not available. There was low certainty evidence for an increased risk for the rare occurrence of atypical femoral fractures (0.06 to 0.08 more in 1000) and osteonecrosis of the jaw (0.22 more in 1000) with bisphosphonates (most evidence for alendronate). The evidence for these rare outcomes and for rebound fractures with denosumab was very uncertain. Younger (lower risk) females have high willingness to be screened. A minority of postmenopausal females at increased risk for fracture may accept treatment. Further, there is large heterogeneity in the level of risk at which patients may be accepting of initiating treatment, and treatment effects appear to be overestimated.

CONCLUSION

An offer of 2-step screening with risk assessment and BMD measurement to selected postmenopausal females with low prevalence of prior fracture probably results in a small reduction in the risk of clinical fragility fracture and hip fracture compared to no screening. These findings were most applicable to the use of clinical FRAX for risk assessment and were not replicated in the offer-to-screen population where the rate of response to mailed screening questionnaires was low. Limited direct evidence on harms of screening were available; using study data to provide estimates, there may be a moderate degree of overdiagnosis of high risk for fracture to consider. The evidence for younger females and males is very limited. The benefits of screening and treatment need to be weighed against the potential for harm; patient views on the acceptability of treatment are highly variable.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO): CRD42019123767.

Update on trabecular bone score

Trabecular bone score (TBS) is an indirect and noninvasive measure of bone quality. A low TBS indicates degraded bone microarchitecture, predicts osteoporotic fracture, and is partially independent of clinical risk factors and bone mineral density (BMD). There is substantial evidence supporting the use of TBS to assess vertebral, hip, and major osteoporotic fracture risk in postmenopausal women, as well as to assess hip and major osteoporotic fracture risk in men aged > 50 years. TBS complements BMD information and can be used to adjust the FRAX (Fracture Risk Assessment) score to improve risk stratification. While TBS should not be used to monitor antiresorptive therapy, it may be potentially useful for monitoring anabolic therapy. There is also a growing body of evidence indicating that TBS is particularly useful as an adjunct to BMD for fracture risk assessment in conditions associated with increased fracture risk, such as type-2 diabetes, chronic corticosteroid excess, and other conditions wherein BMD readings are often misleading. The interference of abdominal soft tissue thickness (STT) on TBS should also be considered when interpreting these findings because image noise can impact TBS evaluation. A new TBS software version based on an algorithm that accounts for STT rather than BMI seems to correct this technical limitation and is under development. In this paper, we review the current state of TBS, its technical aspects, and its evolving role in the assessment and management of several clinical conditions.

ACR Appropriateness Criteria® Osteoporosis and Bone Mineral Density: 2022 Update

Osteoporosis constitutes a significant public health risk. An estimated 10.2 million adults in the United States >50 years of age have osteoporosis, a systemic condition that weakens the bones increasing the susceptibility for fractures. Approximately one-half of women and nearly one-third of men >50 years of age will sustain an osteoporotic fracture. These fractures are associated with a decrease in quality of life, diminished physical function, and reduced independence. Dual-energy X-ray absorptiometry (DXA) is the primary imaging modality used to screen for osteoporosis in women >65 years of age and men >70 years of age. DXA may be used in patients <65 years of age to evaluate bone mass density if there are additional risk factors. In certain situations, vertebral fracture assessment and trabecular bone score may further predict fracture risk, particularly in patients who are not yet osteoporotic but are in the range of osteopenia. Quantitative CT is useful in patients with advanced degenerative changes in the spine. Given the proven efficacy of pharmacologic therapy, the role of imaging to appropriately identify and monitor high-risk individuals is critical in substantially reducing osteoporosis-associated morbidity and mortality, and reducing the considerable cost to the health care system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Clinical observation of diminished bone quality and quantity through longitudinal HR-pQCT-derived remodeling and mechanoregulation

High resolution peripheral quantitative computed tomography (HR-pQCT) provides methods for quantifying volumetric bone mineral density and microarchitecture necessary for early diagnosis of bone disease. When combined with a longitudinal imaging protocol and finite element analysis, HR-pQCT can be used to assess bone formation and resorption (i.e., remodeling) and the relationship between this remodeling and mechanical loading (i.e., mechanoregulation) at the tissue level. Herein, 25 patients with a contralateral distal radius fracture were imaged with HR-pQCT at baseline and 9-12 months follow-up: 16 patients were prescribed vitamin D3 with/without calcium supplement based on a blood biomarker measures of bone metabolism and dual-energy X-ray absorptiometry image-based measures of normative bone quantity which indicated diminishing (n = 9) or poor (n = 7) bone quantity and 9 were not. To evaluate the sensitivity of this imaging protocol to microstructural changes, HR-pQCT images were registered for quantification of bone remodeling and image-based micro-finite element analysis was then used to predict local bone strains and derive rules for mechanoregulation. Remodeling volume fractions were predicted by both average values of trabecular and cortical thickness and bone mineral density (R² > 0.8), whereas mechanoregulation was affected by dominance of the arm and group classification (p < 0.05). Overall, longitudinal, extended HR-pQCT analysis enabled the identification of changes in bone quantity and quality too subtle for traditional measures.

The clinician's guide to prevention and treatment of osteoporosis

Osteoporosis is the most common metabolic bone disease in the USA and the world. It is a subclinical condition until complicated by fracture(s). These fractures place an enormous medical and personal burden on individuals who suffer from them and take a significant economic toll. Any new fracture in an adult aged 50 years or older signifies imminent elevated risk for subsequent fractures, particularly in the year following the initial fracture. What a patient perceives as an unfortunate accident may be seen as a sentinel event indicative of bone fragility and increased future fracture risk even when the result of considerable trauma. Clinical or subclinical vertebral fractures, the most common type of osteoporotic fractures, are associated with a 5-fold increased risk for additional vertebral fractures and a 2- to 3-fold increased risk for fractures at other sites. Untreated osteoporosis can lead to a vicious cycle of recurrent fracture(s), often resulting in disability and premature death. In appropriate patients, treatment with effective antifracture medication prevents fractures and improves outcomes. Primary care providers and medical specialists are critical gatekeepers who can identify fractures and initiate proven osteoporosis interventions. Osteoporosis detection, diagnosis, and treatment should be routine practice in all adult healthcare settings. The Bone Health and Osteoporosis Foundation (BHOF) - formerly the National Osteoporosis Foundation - first published the Clinician's Guide in 1999 to provide accurate information on osteoporosis prevention and treatment. Since that time, significant improvements have been made in diagnostic technologies and treatments for osteoporosis. Despite these advances, a disturbing gap persists in patient care. At-risk patients are often not screened to establish fracture probability and not educated about fracture prevention. Most concerning, the majority of highest risk women and men who have a fracture(s) are not diagnosed and do not receive effective, FDA-approved therapies. Even those prescribed appropriate therapy are unlikely to take the medication as prescribed. The Clinician's Guide offers concise recommendations regarding prevention, risk assessment, diagnosis, and treatment of osteoporosis in postmenopausal women and men aged 50 years and older. It includes indications for bone densitometry as well as fracture risk thresholds for pharmacologic intervention. Current medications build bone and/or decrease bone breakdown and dramatically reduce incident fractures. All antifracture therapeutics treat but do not cure the disease. Skeletal deterioration resumes sooner or later when a medication is discontinued-sooner for nonbisphosphonates and later for bisphosphonates. Even if normal BMD is achieved, osteoporosis and elevated risk for fracture are still present. The diagnosis of osteoporosis persists even if subsequent DXA T-scores are above - 2.5. Ongoing monitoring and strategic interventions will be necessary if fractures are to be avoided. In addition to pharmacotherapy, adequate intake of calcium and vitamin D, avoidance of smoking and excessive alcohol intake, weight-bearing and resistance-training exercise, and fall prevention are included in the fracture prevention armamentarium. Where possible, recommendations in this guide are based on evidence from RCTs; however, relevant published data and guidance from expert clinical experience provides the basis for recommendations in those areas where RCT evidence is currently deficient or not applicable to the many osteoporosis patients not considered for RCT participation due to age and morbidity.

Effect of degeneration on bone mineral density, trabecular bone score and CT Hounsfield unit measurements in a spine surgery patient population

This study investigated the impact of spinal degeneration on bone mineral density (BMD), trabecular bone score (TBS), and CT Hounsfield units in an at-risk population. We found that BMD was increased by degeneration, whereas TBS and HU were unaffected. These findings support that TBS is not adversely affected by spinal degeneration.

INTRODUCTION

This study evaluated the impact of spinal degeneration on BMD and TBS measured by dual-energy x-ray absorptiometry (DXA) and on CT HU in a spine surgery patient population.

METHODS

A retrospective study of 63 patients referred for consideration of spine surgery or with history of spine surgery was performed. Patients were included if a DXA scan and a CT containing the lumbar spine were obtained within 18 months of each other. DXA data were collected and analyzed by vertebral level. Individual vertebrae were assessed for degenerative changes by qualitative evaluation of the anterior and posterior elements using CT. Degeneration scores were compared to BMD T-scores, TBS and CT HU at individual vertebral levels L1-4, and after applying International Society for Clinical Densitometry (ISCD) criteria for excluding vertebrae from diagnostic consideration.

RESULTS

Mean patient age and BMI were 67.2 years and 27.8 kg/m², respectively; 79.4% were female. Mean (SD) lowest T-scores of the hip, spine, and lowest overall T-score were - 1.3 (1.4), - 1.7 (0.9), and - 1.9 (1.0), respectively. Osteoporosis was present by T-score in 38% and osteopenia in 52%; 10% had a history of osteoporotic fracture. The mean degeneration score of individual vertebrae was 4.1 on a 0-6 scale. T-score correlated moderately with degeneration score (Spearman's rho 0.484, p < 0.001), whereas TBS and HU were unrelated. ISCD excluded vertebrae had a higher degeneration score than included vertebrae (p =  < 0.001).

CONCLUSIONS

In a spine surgery population, TBS and CT HU values are unrelated to degeneration score and thus appear unaffected by lumbar vertebral degenerative changes. Additionally, these data support the ISCD criteria for vertebral exclusion.

Changes in trabecular bone score and bone density in female adolescents with anorexia nervosa: a longitudinal study

Impaired bone health is a common complication of anorexia nervosa (AN). We aimed to assess longitudinal changes in bone mineral density (BMD) and trabecular bone score (TBS), a measure of bone quality, in female adolescents with anorexia nervosa (AN). We conducted a retrospective longitudinal study of 41 female adolescents with AN who underwent two dual-energy X-ray absorptiometry (DXA) scans. Clinical data, including age, weight, height, body mass index (BMI), and DXA measurements were retrieved from the medical charts. Lumbar bone mineral apparent density (BMAD) was calculated to correct for size. Changes (Δ) in BMD, BMAD, and TBS were examined for correlations with clinical characteristics. Mean ages at the time of DXA scans were 14.8±1.9 and 16.8±2.0 years. There was a significant improvement in anthropometric parameters and DXA measurements at the second DXA scan. However, these values were still significantly lower than expected in the general population. The Δlumbar BMD Z-score was 0.3±0.7, the Δlumbar BMAD Z-score was 0.2±0.7 and the ΔTBS Z-score was 0.5±0.7. ΔTBS Z-score was positively correlated with Δheight Z-score, Δweight Z-score and ΔBMI Z-scores, and negatively correlated height Z-score, weight Z-score and TBS Z-scores at the first DXA scan (p<0.05). Δheight Z-score, ΔBMI Z-score and the progression from early to late puberty were identified as significant independent predictors of Δlumbar BMAD Z-score (p<0.05). During two years of treatment, both BMD and TBS increased significantly. Improvement in height and in weight status, and progression in puberty are predictors of improvement in BMD and TBS.

Trabecular Bone Score in Rheumatic Disease

PURPOSE OF REVIEW

Patients with rheumatic disease are at high risk of low bone mass and osteoporotic fracture. Trabecular bone score (TBS), derived from lumbar spine dual-energy x-ray absorptiometry (DXA), is a novel measure of bone texture that independently predicts fracture risk. This review examines the role of TBS in rheumatic disease including fracture prediction.

RECENT FINDINGS

Most studies concerning TBS and rheumatic disease are cross-sectional, with consistent evidence of lower TBS in patients with rheumatic disease compared to controls. Recent studies have shown association and predictive ability of TBS for prevalent fracture, and the few longitudinal studies showed predictive ability of TBS for incident fracture. TBS in ankylosing spondylitis is of interest given the high rates of vertebral fracture and technical difficulty with lumbar spine bone mineral density. TBS degradation has been associated with disease activity in ankylosing spondylitis, systemic sclerosis, and rheumatoid arthritis. Glucocorticoid exposure is associated with lower TBS, and predicts prevalent fracture, in patients with rheumatic conditions.

Osteoporosis in 10 years time: a glimpse into the future of osteoporosis

Patients living with osteoporosis are projected to increase dramatically in the next decade. Alongside the forecasted increased societal and economic burden, we will live a crisis of fractures. However, we will have novel pharmacological treatment to face this crisis and, more importantly, new optimized treatment strategies. Fracture liaison services will be probably implemented on a large scale worldwide, helping to prevent additional fractures in high-risk patients. In the next decade, novel advances in the diagnostic tools will be largely available. Moreover, new and more precise fracture risk assessment tools will change our ability to detect patients at high risk of fractures. Finally, big data and artificial intelligence will help us to move forward into the world of precision medicine. In the present review, we will discuss the future epidemiology and costs of osteoporosis, the advances in early and accurate diagnosis of osteoporosis, with a special focus on biomarkers and imaging tools. Then we will examine new and refined fracture risk assessment tools, the role of fracture liaison services, and a future perspective on osteoporosis treatment.

Evaluating Patients for Secondary Causes of Osteoporosis

PURPOSE OF REVIEW

This review provides suggestions for the evaluation of patients with osteoporosis in order to assure that the diagnosis is correct, to identify potentially correctable conditions contributing to skeletal fragility and fracture risk, and to assist in individualizing management decisions.

RECENT FINDINGS

Some patients who appear to have osteoporosis have another skeletal disease, such as osteomalacia, that requires further evaluation and treatment that is different than for osteoporosis. Many patients with osteoporosis have contributing factors (e.g., vitamin D deficiency, high fall risk) that should be addressed before and after starting treatment to assure that treatment is effective and safe. Evaluation includes a focused medical history, skeletal-related physical examination, assessment of falls risk, appropriate laboratory tests, and rarely transiliac double-tetracycline labeled bone biopsy. Evaluation of patients with osteoporosis before starting treatment is essential for optimizing clinical outcomes.

Diagnostic, treatment, and follow-up of osteoporosis-position statement of the Latin American Federation of Endocrinology

The Latin American Federation of Endocrinology position statement on osteoporosis was developed by endocrinologists from 9 countries. It encompasses the definition, diagnosis, treatment, and follow-up of the disease, the identification of barriers to healthcare, and proposals to improve the disease care in the region.

INTRODUCTION

There is a gap in the understanding of osteoporosis in Latin America. The objective of this work is to state the position of the Latin American Federation of Endocrinology on osteoporosis care in postmenopausal women to better bridge this gap.

METHODS

An experts' panel was formed comprising of 11 endocrinologists from 9 countries. A data search was conducted with a conceptual approach and data selection was based on the hierarchy of the EBHC pyramid. Unpublished data was considered for local epidemiological data and expert opinion for the identification of barriers to healthcare. An expert consensus based on the Delphi methodology was carried out. Experts were asked to respond on a 5-point Likert Scale to two provided answers to guiding questions.

RESULTS

Consensus was agreed on the answer for the questions with the higher median on the Likert scale and synthetized on 16 statements covering the definition of osteoporosis, diagnostic approach, treatment options, and follow-up. Besides clinical topics, unmet needs in osteoporosis were identified in relation to local epidemiological data, barriers to treatment, and misclassification of programs within health systems.

CONCLUSIONS

Through a process based on recognized methodological tools, FELAEN's position on osteoporosis was developed. This made it possible to state an optimum scenario for the care of the disease and helped to identify knowledge gaps. There is great variability in the approach to osteoporosis in Latin America and barriers in all the stages of healthcare persist.

Critical review of bone health, fracture risk and management of bone fragility in diabetes mellitus

The risk of fracture is increased in both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). However, in contrast to the former, patients with T2DM usually possess higher bone mineral density. Thus, there is a considerable difference in the pathophysiological basis of poor bone health between the two types of diabetes. Impaired bone strength due to poor bone microarchitecture and low bone turnover along with increased risk of fall are among the major factors behind elevated fracture risk. Moreover, some antidiabetic medications further enhance the fragility of the bone. On the other hand, antiosteoporosis medications can affect the glucose homeostasis in these patients. It is also difficult to predict the fracture risk in these patients because conventional tools such as bone mineral density and Fracture Risk Assessment Tool score assessment can underestimate the risk. Evidence-based recommendations for risk evaluation and management of poor bone health in diabetes are sparse in the literature. With the advancement in imaging technology, newer modalities are available to evaluate the bone quality and risk assessment in patients with diabetes. The purpose of this review is to explore the pathophysiology behind poor bone health in diabetic patients. Approach to the fracture risk evaluation in both T1DM and T2DM as well as the pragmatic use and efficacy of the available treatment options have been discussed in depth.

Trabecular Bone Score in Children and Adolescents With Inflammatory Bowel Diseases

INTRODUCTION

Trabecular bone score (TBS) is a textural index that evaluates bone microarchitecture of the lumbar spine. Our aim was to assess TBS in children with inflammatory bowel diseases and to evaluate correlations with clinical, laboratory and densitometric variables.

METHODS

A retrospective study of TBS and areal bone mineral density measurements by dual-energy X-ray absorptiometry (DXA) of children with either Crohn's disease (CD) or ulcerative colitis (UC). Bone mineral apparent density was calculated for size adjustment. TBS Z-score for each child were calculated based on data from a healthy population of similar age and gender distribution. Variables significantly associated with TBS were included in stepwise linear regression models to examine independent predictors of TBS.

RESULTS

Fifty patients (age at DXA scan 13.8 ± 3.0 years, 29 males) were included. No significant differences were observed between the patients with CD and UC, in age at diagnosis, age at DXA scan and disease duration. The mean TBS of patients with CD (n = 35) was lower than of patients with UC (n = 15): 1.340 ± 0.080 vs 1.395 ± 0.092, p = 0.040. The mean TBS Z-score of patients with CD, -0.443 ± 0.788, was significantly lower than expected in healthy children (p = 0.002), while the mean TBS Z-score of patients with UC, 0.231 ± 0.685, was similar to that of healthy children (p = 0.212). In the stepwise linear regression analysis, BMI Z-score at diagnosis, phosphorus level at diagnosis and age at the time of the DXA scan were significant independent predictors of TBS (r² = 0.604; β = 0.037, 95% confidence interval (CI) for β 0.022-0.051, p < 0.001; β = 0.045, 95% CI: 0.017-0.073, p = 0.002; and β = 0.031, 95% CI: 0.005-0.021, p < 0.002, respectively).

CONCLUSIONS

TBS is significantly reduced in pediatric patients with CD but not in patients with UC. This finding likely reflects the effect of CD on bone microarchitecture.

Premenopausal and early postmenopausal trabecular bone score (TBS) and fracture risk: Study of Women's Health Across the Nation (SWAN)

BACKGROUND

Evidence that trabecular bone score (TBS), an index of bone microstructure, is a risk factor for future fracture comes mainly from studies of late postmenopausal women.

OBJECTIVE

To discern whether premenopausal TBS or early postmenopausal TBS predict fracture.

DESIGN

A 22-year, prospective analysis from the Study of Women's Health Across Nation.

SETTING

Community-based cohort.

PARTICIPANTS

272 Black, 174 Japanese, and 364 White women.

MAIN OUTCOME MEASURES

Incident fractures: 292 in premenopausal sample and 141 in early postmenopausal sample.

RESULTS

Separate Cox proportional hazard regressions modeled time to incident fracture as a function of TBS measured during premenopause or early postmenopause. Models were initially adjusted for age, race/ethnicity, SWAN clinical site, body mass index, use of calcium, vitamin D, bone beneficial or bone adverse medication. Next, we added lumbar spine (LS) or femoral neck (FN) bone mineral density (BMD) and, finally, history of prior fracture, to the models. For each standard deviation decrement in premenopausal TBS, fracture hazard was elevated by 17% (relative hazard [RH] 1.17 [95% CI, 1.02-1.35]); after adjusting for LS or FN BMD, the relation between premenopausal TBS and fracture was no longer statistically significant. There was a similar-magnitude, marginally statistically significant, association between early postmenopausal TBS and fracture, unadjusted for BMD (RH 1.15 [0.95-1.39]).

CONCLUSIONS

Variation in premenopausal TBS is related to fracture risk, but this association is not independent of BMD.

Combining Frailty and Trabecular Bone Score Did Not Improve Predictive Accuracy in Risk of Major Osteoporotic Fractures

It is recognized that the trabecular bone score (TBS) provides skeletal information, and frailty measurement is significantly associated with increased risks of adverse health outcomes. Given the suboptimal predictive power in fracture risk assessment tools, we aimed to evaluate the combination of frailty and TBS regarding predictive accuracy for risk of major osteoporotic fracture (MOF). Data from the prospective longitudinal study of CaMos (Canadian Multicentre Osteoporosis Study) were used for this study. TBS values were estimated using lumbar spine (L₁ to L₄ ) dual-energy X-ray absorptiometry (DXA) images; frailty was evaluated by a frailty index (FI) of deficit accumulation. Outcome was time to first incident MOF during the follow-up. We used the Harrell's C-index to compare the model predictive accuracy. The Akaike information criterion, likelihood ratio test, and net reclassification improvement (NRI) were used to compare model performances between the model combining frailty and TBS (subsequently called "FI + TBS"), FI-alone, and TBS-alone models. We included 2730 participants (mean age 69 years; 70% women) for analyses (mean follow-up 7.5 years). There were 243 (8.90%) MOFs observed during follow-up. Participants with MOF had significantly higher FI (0.24 versus 0.20) and lower TBS (1.231 versus 1.285) than those without MOF. FI and TBS were significantly related with MOF risk in the model adjusted for FRAX with bone mineral density (BMD) and other covariates: hazard ratio (HR) = 1.26 (95% confidence interval [CI] 1.11-1.43) for per-SD increase in FI; HR = 1.38 (95% CI 1.21-1.59) for per-SD decrease in TBS; and these associations showed negligible attenuation (HR = 1.24 for per-SD increase in FI, and 1.35 for per-SD decrease in TBS) when combined in the same model. Although the model FI + TBS was a better fit to the data than FI-alone and TBS-alone, only minimal and nonsignificant enhancement of discrimination and NRI were observed in FI + TBS. To conclude, frailty and TBS are significantly and independently related to MOF risk. Larger studies are warranted to determine whether combining frailty and TBS can yield improved predictive accuracy for MOF risk. © 2020 American Society for Bone and Mineral Research.

Bone mineral density and trabecular bone score in treatment-naïve patients with non-cirrhotic hepatitis C virus infection

We studied 112 treatment-naïve chronic HCV patients without cirrhosis, and we found that, especially HCV+ postmenopausal women, they had lower TBS and BMD values than healthy controls. This suggests that HCV infection is an independent risk factor for osteoporosis, and therefore, screening for osteoporosis in postmenopausal HCV+ women should be considered.

PURPOSE

To know whether patients in earlier stages of chronic HCV infection are at increased risk of developing low bone mass and bone microarchitectural changes and whether there is an association between bone metabolism and the severity of the liver disease.

METHODS

We studied 112 treatment-naïve chronic HCV outpatients and 233 healthy age- and sex-matched controls. Bone mineral density (BMD) and trabecular bone score (TBS) were assessed by DXA. Serum 25(OH)D, PTH, P1NP, and CTX were determined by electrochemiluminescence.

RESULTS

TBS values were significantly lower in HCV patients than in controls, both considering the population as a whole (1.337 ± 0.119 vs. 1.377 ± 0.122; p < 0.005) and after stratifying by sex (1.347 ± 0.12 vs. 1.381 ± 0.13 in men and 1.314 ± 0.10 vs. 1.369 ± 0.11 in women). The difference remained significant (p < 0.0001 in all cases) after adjusting for confounders. BMD was also lower in HCV patients (lumbar spine, 0.935 ± 0.151 vs. 0.991 ± 0.143 g/cm², p 0.001; femoral neck, 0.764 ± 0.123 vs. 0.818 ± 0.123 g/cm², p 0.0001; total hip, 0.926 ± 0.148 vs. 0.963 ± 0.132 g/cm², p 0.02), although, after adjustment, differences kept a clear trend towards statistical significance in women at the lumbar spine and femoral neck. However, in men and at the total hip in women, differences were no longer significant. We find no relationship between these parameters and the severity of the disease. No significant difference was observed in PTH and 25OHD status after adjustment. Finally, serum P1NP, but not CTX, was higher in HCV patients.

CONCLUSIONS

Our findings suggest that HCV infection is an independent risk factor for osteoporosis, especially among postmenopausal women. Therefore, the appropriateness of screening for osteoporosis in postmenopausal HCV-positive women should be considered.

Trabecular Bone Score Declines During the Menopause Transition: The Study of Women's Health Across the Nation (SWAN)

CONTEXT

Rapid bone density loss starts during the menopause transition (MT). Whether other components of bone strength deteriorate before the final menstrual period (FMP) remains uncertain.

OBJECTIVE

To discern whether trabecular bone score (TBS) declines during the MT.

DESIGN

An 18-year longitudinal analysis from the Study of Women's Health Across Nation.

SETTING

Community-based cohort.

PARTICIPANTS

A total of 243 black, 164 Japanese, and 298 white, initially pre- or early perimenopausal women, who experienced their FMP.

MAIN OUTCOME MEASURES

TBS, an indicator of bone strength.

RESULTS

Multivariable mixed effects regressions fitted piecewise linear models to repeated measures of TBS as a function of time before or after the FMP; covariates were age at FMP, race/ethnicity, and body mass index. Prior to 1.5 years before the FMP, in the referent individual (a white woman with age at FMP of 52.2 years and body mass index of 28.0 kg/m2), TBS evidenced no change (slope 0.12% per year, P = 0.2991). TBS loss began 1.5 years before the FMP, declining by 1.16% annually (P < 0.0001). Starting 2 years after the FMP, annual rate of TBS loss lessened to 0.89% (P < 0.0001). In the 5 years before through the 5 years after the FMP, in the referent individual, total TBS decline was 6.3% (P < 0.0001), but black participants' total TBS loss was 4.90% (P = 0.0008, difference in black and white 10-year change). Results for Japanese did not differ from those of white women.

CONCLUSIONS

The occurrence of an MT-related decline in TBS supports the thesis that this period is particularly damaging to skeletal integrity.

Do Additional Clinical Risk Factors Improve the Performance of Fracture Risk Assessment Tool (FRAX) Among Postmenopausal Women? Findings From the Women's Health Initiative Observational Study and Clinical Trials

The ability of the fracture risk assessment tool (FRAX) to discriminate between women who do and do not experience major osteoporotic fractures (MOFs) is suboptimal. Adding common clinical risk factors may improve discrimination. We used data from the Women's Health Initiative, a prospective study of women aged 50 to 79 years at baseline (n = 99,413; n = 5722 in BMD subset) enrolled at 40 US clinical centers. The primary outcome was incident MOFs assessed annually during 10 years' follow-up. For prediction of incident MOF, we examined the area under the receiver operatic characteristic curve (AUC) and net reclassification index (NRI) of the FRAX model alone and FRAX plus additional risk factors (singly or together: type 2 diabetes mellitus, frequent falls [≥2 falls in the past year], vasomotor symptoms, self-reported physical function score [RAND 36-item Health Survey subscale), and lumbar spine BMD). For NRI calculations, high risk was defined as predicted MOF risk ≥20%. We also assessed calibration as observed MOF events/expected MOF events. The AUC value for FRAX without BMD information was 0.65 (95% CI, 0.65 to 0.66). Compared with the FRAX model (without BMD), the AUC value was not improved by the addition of vasomotor symptoms, diabetes, or frequent falls, but was minimally increased by adding physical function score (AUC 0.66, 95% CI, 0.66 to 0.67). FRAX was well-calibrated for MOF prediction. The NRI of FRAX + additional variables versus FRAX alone was 5.7% (p < 0.001) among MOF cases and -1.7% among noncases (p > 0.99). Additional variables (diabetes, frequent falls, vasomotor symptoms, physical function score, or lumbar spine BMD) did not yield meaningful improvements in NRI or discrimination of FRAX for MOFs. Future studies should assess whether tools other than FRAX provide superior discrimination for prediction of MOFs. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

The utility and limitations of using trabecular bone score with FRAX

PURPOSE OF REVIEW

Trabecular bone score (TBS) is a texture index derived from the lumbar spine dual-energy X-ray absorptiometry which can assess skeletal quality and provide information about fracture risk independent of bone mineral density (BMD). TBS is useful in assessing osteoporotic fracture risk, with lower TBS values associated with increased fracture risk. In this article, we review the current state of TBS, including its utility and limitations in the assessment and management of osteoporosis, with particular emphasis on the recent literature.

RECENT FINDINGS

Ten-year fracture risk assessment using the FRAX tool can be improved through the use of a TBS adjustment. The use of TBS-adjusted FRAX can change management in a modest but significant number of patients, particularly in those close to an intervention threshold. Change in lumbar spine TBS for patients undergoing antiresorptive treatment is not a useful indicator of antifracture effect.

SUMMARY

Lumbar spine TBS provides information complementary to conventional BMD, and has been shown to be clinically useful for enhancing fracture risk prediction.

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

Guidance is provided in a European setting on the assessment and treatment of postmenopausal women at risk from fractures due to osteoporosis.

INTRODUCTION

The International Osteoporosis Foundation and European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis published guidance for the diagnosis and management of osteoporosis in 2013. This manuscript updates these in a European setting.

METHODS

Systematic reviews were updated.

RESULTS

The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporosis and assessment of fracture risk; general and pharmacological management of osteoporosis; monitoring of treatment; assessment of fracture risk; case-finding strategies; investigation of patients; health economics of treatment. The update includes new information on the evaluation of bone microstructure evaluation in facture risk assessment, the role of FRAX® and Fracture Liaison Services in secondary fracture prevention, long-term effects on fracture risk of dietary intakes, and increased fracture risk on stopping drug treatment.

CONCLUSIONS

A platform is provided on which specific guidelines can be developed for national use.

Cortical and trabecular bone microarchitecture as an independent predictor of incident fracture risk in older women and men in the Bone Microarchitecture International Consortium (BoMIC): a prospective study

BACKGROUND

Although areal bone mineral density (aBMD) assessed by dual-energy x-ray absorptiometry (DXA) is the clinical standard for determining fracture risk, most older adults who sustain a fracture have T scores greater than -2·5 and thus do not meet the clinical criteria for osteoporosis. Importantly, bone fragility is due to low BMD and deterioration in bone structure. We assessed whether indices of high-resolution peripheral quantitative CT (HR-pQCT) were associated with fracture risk independently of femoral neck aBMD and the Fracture Risk Assessment Tool (FRAX) score.

METHODS

We assessed participants in eight cohorts from the USA (Framingham, Mayo Clinic), France (QUALYOR, STRAMBO, OFELY), Switzerland (GERICO), Canada (CaMos), and Sweden (MrOS). We used Cox proportional hazard ratios (HRs) to estimate the association between HR-pQCT bone indices (per 1 SD of deficit) and incident fracture, adjusting for age, sex, height, weight, and cohort, and then additionally for femoral neck DXA aBMD or FRAX.

FINDINGS

7254 individuals (66% women and 34% men) were assessed. Mean baseline age was 69 years (SD 9, range 40-96). Over a mean follow-up of 4·63 years (SD 2·41) years, 765 (11%) participants had incident fractures, of whom 633 (86%) had femoral neck T scores greater than -2·5. After adjustment for age, sex, cohort, height, and weight, peripheral skeleton failure load had the greatest association with risk of fracture: tibia HR 2·40 (95% CI 1·98-2·91) and radius 2·13 (1·77-2·56) per 1 SD decrease. HRs for other bone indices ranged from 1·12 (95% CI 1·03-1·23) per 1 SD increase in tibia cortical porosity to 1·58 (1·45-1·72) per 1 SD decrease in radius trabecular volumetric bone density. After further adjustment for femoral neck aBMD or FRAX score, the associations were reduced but remained significant for most bone parameters. A model including cortical volumetric bone density, trabecular number, and trabecular thickness at the distal radius and a model including these indices plus cortical area at the tibia were the best predictors of fracture.

INTERPRETATION

HR-pQCT indices and failure load improved prediction of fracture beyond femoral neck aBMD or FRAX scores alone. Our findings from a large international cohort of men and women support previous reports that deficits in trabecular and cortical bone density and structure independently contribute to fracture risk. These measurements and morphological assessment of the peripheral skeleton might improve identification of people at the highest risk of fracture.

FUNDING

National Institutes of Health National Institute of Arthritis Musculoskeletal and Skin Diseases.

Comparison of Methods for Improving Fracture Risk Assessment in Diabetes: The Manitoba BMD Registry

Type 2 diabetes is a risk factor for fracture independent of FRAX (fracture risk assessment) probability. We directly compared four proposed methods to improve the performance of FRAX for type 2 diabetes by: (1) including the rheumatoid arthritis (RA) input to FRAX; (2) making a trabecular bone score (TBS) adjustment to FRAX; (3) reducing the femoral neck T-score input to FRAX by 0.5 SD; and (4) increasing the age input to FRAX by 10 years. We examined major osteoporotic fractures (MOFs) and hip fractures (HFs) over a mean of 8.3 years observation among 44,543 women and men 40 years of age or older (4136 with diabetes) with baseline lumbar spine and hip DXA from 1999 through 2016. Controlled for unadjusted FRAX probability, diabetes was associated with an increased risk for MOFs and HFs. All four FRAX adjustments attenuated the effect of diabetes, but a residual effect of diabetes was seen on MOF risk after TBS adjustment, and on HF risk after the RA and TBS adjustments. Among those with diabetes, unadjusted FRAX risk underestimated MOF (observed/predicted ratio 1.15; 95% CI, 1.03 to 1.28), but this was no longer significant after applying the diabetes adjustments. HF risk was more severely underestimated (observed/predicted ratio 1.85; 95% CI, 1.51 to 2.20) and was only partially corrected with the diabetes adjustments (still significant for the RA and TBS adjustments). Among those with diabetes, there was moderate reclassification based upon a fixed MOF cut-off of 20% (4.1% to 7.1%) or fixed HF cut-off of 3% (5.7% to 16.5%). Net reclassification improvement increased for MOF with each of the diabetes adjustments (range 3.9% to 5.6% in the diabetes subgroup). In conclusion, each of the proposed methods for addressing limitations in the ability of FRAX to assess fracture risk in individuals with diabetes was found to improve performance, though no single method was optimal in all settings. © 2018 American Society for Bone and Mineral Research.

Less strict intervention thresholds for the FRAX and TBS-adjusted FRAX predict clinical fractures in osteopenic postmenopausal women with no prior fractures

Little is known about the clinical relevance of treating post-menopausal women with no prior history of fragility fracture and bone mineral densities (BMD) within the osteopenic range. In recent years, in addition to BMD and FRAX fracture probability assessments, a surrogate measure of bone micro-architecture quality, called the trabecular bone score (TBS), has been proven to predict future fragility fractures independently of both BMD and the FRAX. In this retrospective analysis of a follow-up study, we compared three risk assessment instruments-the FRAX, the TBS, and a TBS-adjusted FRAX score-in their ability, to predict future fragility fractures over a minimum of five years of follow-up among post-menopausal osteopenic women with no prior fragility fractures. We also sought to determine if more- versus less-stringent criteria were better when stratifying patients into higher-risk patients warranting osteoporosis-targeted intervention versus lower-risk patients in whom intervention would usually be deemed unnecessary. Over a mean 5.2 years follow-up, 18 clinical fragility fractures were documented among 127 women in the age 50 years and older (mean age = 66.1). On multivariate analysis utilizing regression models and Kaplan-Meier curve analysis, less-stringent criteria for the FRAX and TBS-adjusted FRAX were capable of predicting future fractures (with sensitivity/specificity of 83/31; 39/77 and 78/50% for TBS, FRAX and TBS-adjusted FRAX, respectively), while more-stringent criteria were incapable of doing so (with sensitivity/specificity of 56/60; 39/77 and 39/74 for TBS, FRAX and TBS-adjusted FRAX, respectively). Neither TBS threshold alone was a significant predictor of future fracture in our study. However, hazard ratio analysis revealed slight superiority of the TBS-adjusted FRAX over the FRAX alone (HR = 3.09 vs. 2.79). Adjusting the FRAX tool by incorporating the TBS may be useful to optimize the detection of post-menopausal osteopenic women with no prior fractures who warrant osteoporosis-targeted therapy.

Effect of vertebral exclusion on TBS and FRAX calculations

Degenerative changes falsely elevate BMD; however, their impact on TBS is unclear. This study examined how spinal degenerative changes affect TBS-adjusted fracture risk (FRAX). In a majority, but not all patients in this sample, TBS decreased after exclusion of vertebrae with degenerative change. Therefore, vertebral exclusion for TBS is suggested.

INTRODUCTION

Spinal degenerative changes elevate DXA-measured BMD, but reports find trabecular bone score (TBS) relatively unaffected. However, we observed patients where degenerative changes elevated both. Consequently, this study explored whether vertebral exclusion impacts TBS and subsequently TBS-adjusted FRAX risk.

METHODS

Clinical DXA interpretations of one physician were reviewed; those with vertebrae excluded per ISCD guidance were included in this study. BMD and TBS at L1-4 and from post-exclusion vertebrae were collected and used to adjust fracture risk (FRAX).

RESULTS

Of the patients, 102 had vertebrae excluded; their mean (SD) age, BMI, and lowest T-score were 71.6 (9.5) years, 25.4 (4.5) kg/m², and - 2.8 (1.0), respectively. Compared to L1-4, vertebral exclusion lowered (p < 0.0001) mean spine BMD and TBS by 9.5 and 3.1%, respectively. Vertebral exclusion decreased TBS by 0.040, being lower in 83%. In those with lower TBS, the mean adjusted 10-year fracture risk increased (p < 0.0001) by 0.94 and 0.32% for major osteoporotic (MOF) and hip fracture, respectively, in some risk increased by up to 4%. In those with higher TBS, adjusted risk was reduced, MOF - 0.49% and hip - 0.1%.

CONCLUSION

Vertebral exclusion following ISCD recommendations generally, but not always, lowers TBS. Consequently, the impact on TBS adjusted FRAX risk is variable. In most patients, vertebral exclusion lowers TBS; in some, this could result in a relevant change in calculated fracture risk. It seems reasonable to use TBS values from evaluable vertebrae to adjust FRAX. Further research to determine if vertebral exclusion improves fracture risk prediction is needed.

Assessment of bone quality in patients with diabetes mellitus

Substantial evidence exists that diabetes mellitus is associated with an increased risk of osteoporotic fractures. Low bone strength as well as bone extrinsic factors are probably contributing to the increased bone fragility in diabetes. Bone density and quality are important determinants of bone strength. Although bone mineral density (BMD) and the fracture risk assessment tool (FRAX) are very useful clinical tools in assessing bone strength, they may underestimate the fracture risk in diabetes mellitus. Through advances in new technologies such as trabecular bone score (TBS) and peripheral quantitative computed tomography (pQCT), we can better assess the bone quality and fracture risk of patients with diabetes mellitus. Invasive assessments such as microindentation and histomorphometry have been great complement to the existing bone analysis techniques. Bone turnover markers have been found to be altered in diabetes mellitus patients and may be associated with fractures. This review will give a brief summary of the current development and clinical uses of these assessments.

In which patients does lumbar spine trabecular bone score (TBS) have the largest effect?

BACKGROUND

Lumbar spine TBS, a texture index derived from lumbar spine dual-energy x-ray absorptiometry (DXA) images, enhances fracture prediction. No studies to date have studied a broad range of clinical variables to determine which patients might experience the greatest benefit from the use of TBS.

METHODS

Using the Manitoba BMD Registry, we identified 37,176 subjects with baseline DXA, FRAX®-based fracture probability, lumbar spine TBS, and minimum 5 years of observation. Subgroups considered were based on sex, age, body mass index (BMI), prior fracture, chronic obstructive lung disease (COPD), high alcohol use, rheumatoid arthritis (RA), high glucocorticoid use, osteoporotic femoral neck T-score, number of comorbidities, diabetes, secondary osteoporosis, and prior osteoporosis treatment. Non-traumatic major osteoporotic fractures (MOF, n = 3741) and hip fractures (HF, n = 1008) were identified using population-based health services data. We analyzed baseline TBS using analysis of covariance (ANCOVA). FRAX-adjusted hazard ratios (HR) per SD reduction in TBS were estimated and tested for interactions. Categorical net reclassification improvement (NRI) was estimated using fixed FRAX-based intervention cut-offs.

RESULTS

Adjusted baseline TBS was significantly lower (p ≤ 0.001) for women (-4.2%), osteoporotic hip T-score (-4.0%), COPD (-2.8%), diabetes (-2.6%), high alcohol use (-2.3%), prior fracture (-2.2%), glucocorticoid use (-1.5%), RA (-0.9%) and secondary osteoporosis (-0.8%), whereas recent osteoporosis therapy was associated with greater TBS (+1.5%). HRs per SD reduction in TBS for fracture prediction were larger for age < 65 vs 65+ (MOF p-interaction = 0.004, HF p-interaction < 0.001), without vs with prior fracture (MOF p-interaction = 0.003, HF p-interaction = 0.048), without vs with glucocorticoid use (HF p-interaction = 0.029), lower vs higher comorbidity score (HF p-interaction < 0.001), and without vs with osteoporosis treatment (MOF p-interaction = 0.005). NRI for using the TBS adjustment to FRAX in all subjects was 1.2% for MOF (p = 0.002) and 1.7% for HF (p = 0.016). NRI was greater in subjects age < 65 y (MOF:1.7%, HF:5.6%), no prior fracture (HF: 2.4%), non-osteoporotic T-score (HF: 3.0%), and high glucocorticoid use (MOF: 3.9%).

CONCLUSION

TBS is sensitive to the effects of multiple risk factors for fracture. TBS-adjusted fracture risk assessment resulted in significant improvements for multiple subgroups.