Lumbar Spine Trabecular Bone Score Research Articles

Bone mineral density (BMD) and vertebral trabecular bone score (TBS) for the identification of elderly women at high risk for fracture: the SEMOF cohort study.

To determine the predictive value of the vertebral trabecular bone score (TBS) alone or in addition to bone mineral density (BMD) with regard to fracture risk. Retrospective analysis of the relative contribution of BMD [measured at the femoral neck(FN), total hip (TH), and lumbar spine (LS)] and TBS with regard to the risk of incident clinical fractures in a representative cohort of elderly post-menopausal women previously participating in the Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk study. Complete datasets were available for 556 of 701 women (79%). Mean age 76.1years, LS BMD 0.863g/cm2, and TBS 1.195. LS BMD and LS TBS were moderately correlated (r 2=0.25). After a mean of 2.7±0.8years of follow-up, the incidence of fragility fractures was 9.4%. Age- and BMI-adjusted hazard ratios per standard deviation decrease (95% confidence intervals) were 1.58 (1.16-2.16), 1.77 (1.31-2.39), and 1.59 (1.21-2.09) for LS, FN, and TH BMD, respectively, and 2.01 (1.54-2.63) for TBS. Whereas 58 and 60% of fragility fractures occurred in women with BMD T score ≤-2.5 and a TBS <1.150, respectively, combining these two thresholds identified 77% of all women with an osteoporotic fracture. Lumbar spine TBS alone or in combination with BMD predicted incident clinical fracture risk in a representative population-based sample of elderly post-menopausal women.

Adjusting fracture probability by trabecular bone score.

The aim of the present study was to determine the impact of trabecular bone score on the probability of fracture above that provided by the clinical risk factors utilized in FRAX. We performed a retrospective cohort study of 33,352 women aged 40-99 years from the province of Manitoba, Canada, with baseline measurements of lumbar spine trabecular bone score (TBS) and FRAX risk variables. The analysis was cohort-specific rather than based on the Canadian version of FRAX. The associations between trabecular bone score, the FRAX risk factors and the risk of fracture or death were examined using an extension of the Poisson regression model and used to calculate 10-year probabilities of fracture with and without TBS and to derive an algorithm to adjust fracture probability to take account of the independent contribution of TBS to fracture and mortality risk. During a mean follow-up of 4.7 years, 1754 women died and 1639 sustained one or more major osteoporotic fractures excluding hip fracture and 306 women sustained one or more hip fracture. When fully adjusted for FRAX risk variables, TBS remained a statistically significant predictor of major osteoporotic fractures excluding hip fracture (HR/SD 1.18, 95% CI 1.12-1.24), death (HR/SD 1.20, 95% CI 1.14-1.26) and hip fracture (HR/SD 1.23, 95% CI 1.09-1.38). Models adjusting major osteoporotic fracture and hip fracture probability were derived, accounting for age and trabecular bone score with death considered as a competing event. Lumbar spine texture analysis using TBS is a risk factor for osteoporotic fracture and a risk factor for death. The predictive ability of TBS is independent of FRAX clinical risk factors and femoral neck BMD. Adjustment of fracture probability to take account of the independent contribution of TBS to fracture and mortality risk requires validation in independent cohorts.

The impact of glucocorticoid therapy on trabecular bone score in older women.

We propose that trabecular bone score could be a useful tool for the study of glucocorticoid-associated bone effects. Trabecular bone score alone and lumbar spine bone mineral density (BMD) used in combination with trabecular bone score, but not lumbar spine BMD alone was able to discriminate between glucocorticoid-treated and glucocorticoid-naïve women. Glucocorticoids result in rapid bone loss and an increase in fracture risk that cannot be fully explained by changes in BMD. Trabecular bone score (TBS) correlates with three-dimensional bone micro-architectural parameters and can be derived from grey-level variations within dual energy X-ray absorptiometry (DXA) scans. We propose that TBS could be a useful tool for the study of glucocorticoid-associated bone effects. We assessed the ability of lumbar spine BMD (LS-BMD), TBS, and LS-BMD with TBS (LS-BMD + TBS) to discriminate between healthy women and (i) glucocorticoid-treated women, and (ii) glucocorticoid-naïve women with recent fractures. Older women (n = 484, ages 55-79 years) who had (i) taken prednisolone ≥5 mg/day for >3 months (n = 64), (ii) sustained a recent fracture of the distal forearm (n = 46), proximal humerus (n = 37), vertebra (n = 30) or proximal femur (n = 28), or (iii) were healthy population-based women (n = 279) were recruited. LS-BMD was measured by DXA and TBS values were derived. Compared to healthy, population-based women, women with recent fractures had lower LS-BMD (-0.34 to -1.38) and TBS (-0.38 to -1.04) Z-scores. Glucocorticoid-treated women had lower TBS Z-scores than glucocorticoid-naïve women (-0.80 versus 0) but their LS-BMD Z-scores did not differ (-0.13 versus 0). TBS alone (area under the receiver operating characteristic curve (AUC) = 0.721) and LS-BMD + TBS (AUC = 0.721), but not LS-BMD alone (AUC = 0.572) was able to discriminate between glucocorticoid-treated and glucocorticoid-naïve women. TBS provides additional information regarding glucocorticoid-associated alterations in bone quality. We conclude that TBS may be a useful tool for the further study of glucocorticoid-induced osteoporosis.

Trabecular bone score as an indicator for skeletal deterioration in diabetes.

Trabecular bone score (TBS) is a novel texture index that evaluates the pixel gray-level variations in lumbar spine dual-energy X-ray absorptiometry images and is related to bone microarchitecture independent of bone mineral density (BMD). We investigated lumbar spine TBS as an indicator for skeletal deterioration in diabetes. Cross-sectional data were collected from subjects participating in an ongoing prospective, community-based, cohort study from 2009 to 2010. We included 1229 men and 1529 postmenopausal women older than 50 years in the Ansung cohort. Biochemical parameters, lumbar spine TBS, and BMD from dual-energy X-ray absorptiometry images were measured. Lumbar spine TBS was lower in men with diabetes than in nondiabetic men (1.287 ± 0.005 vs 1.316 ± 0.003, P < .001), whereas lumbar spine BMD was higher in men with diabetes (1.135 ± 0.010 vs 1.088 ± 0.006 g/cm(2)). Lumbar spine TBS was lower in women with diabetes than in nondiabetic women only in an unadjusted model (1.333 ± 0.004 vs 1.353 ± 0.003). However, women younger than 65 years (n = 707) with diabetes had a lower TBS than those without diabetes, even after adjusted for covariates (P < .001). Diabetes was not associated with BMD at femur sites in both genders. TBS was negatively correlated with glycated hemoglobin, fasting plasma glucose, fasting insulin, and homeostasis model assessment for insulin resistance but not with homeostasis model assessment for β-cell function in both genders. The inverse association between lumbar spine TBS and insulin resistance may make it an indicator for determining skeletal deterioration in diabetic patients who have high BMD.

Speed Of Bone Accretion Assessed by Dual X-Ray Absorptiometry (DXA) and Quantitative Ultrasound (QUS) in Mexican Health Workers Cohort Study

s 405 Advantage competitive binding chemiluminescence immunoassay (reference range 10-68 ng/mL, intra-assay precision 3.9% at 20.3 ng/mL, 3.0% at 49.9 ng/ mL, and 3.6% at 57.8 ng/mL, lower limit of sensitivity 7 ng/mL; Quest Diagnostics Clinical Trials Laboratory Test Development Department, Van Nuys, CA, USA) from a central laboratory. Lumbar spine (L2-L4) BMD was measured by DXA (GE Healthcare Lunar Prodigy). Lumbar spine TBS was derived from DXA lumbar spine examinations. Results: Mean serum (25OHD) level was 27.2 12.2 ng/ml and mean BMI was 26.9 5.2 kg/m. Age, weight, height and BMI were not correlated to serum (25OHD). Age, weight, height, BMI and serum (25OHD) were not correlated to TBS. Conclusion: These results suggest that serum (25OHD) is not a determinant of TBS in postmenopausal women. Further research is needed to identify the determinants of TBS in postmenopausal women. Disclosure of Interest: None Declared

Spine bone texture assessed by trabecular bone score (TBS) predicts osteoporotic fractures in men: The Manitoba Bone Density Program

IntroductionOne quarter of osteoporotic fractures occur in men. TBS, a gray-level measurement derived from lumbar spine DXA image texture, is related to microarchitecture and fracture risk independently of BMD. Previous studies reported the ability of spine TBS to predict osteoporotic fractures in women. Our aim was to evaluate the ability of TBS to predict clinical osteoporotic fractures in men. Methods3620 men aged ≥50 (mean 67.6years) at the time of baseline DXA (femoral neck, spine) were identified from a database (Province of Manitoba, Canada). Health service records were assessed for the presence of non-traumatic osteoporotic fracture after BMD testing. Lumbar spine TBS was derived from spine DXA blinded to clinical parameters and outcomes. We used Cox proportional hazard regression to analyze time to first fracture adjusted for clinical risk factors (FRAX without BMD), osteoporosis treatment and BMD (hip or spine). ResultsMean followup was 4.5years. 183 (5.1%) men sustain major osteoporotic fractures (MOF), 91 (2.5%) clinical vertebral fractures (CVF), and 46 (1.3%) hip fractures (HF). Correlation between spine BMD and spine TBS was modest (r=0.31), less than correlation between spine and hip BMD (r=0.63). Significantly lower spine TBS were found in fracture versus non-fracture men for MOF (p<0.001), HF (p<0.001) and CVF (p=0.003). Area under the receiver operating characteristic curve (AUC) for incident fracture discrimination with TBS was significantly better than chance (MOF AUC=0.59, p<0.001; HF AUC=0.67, p<0.001; CVF AUC=0.57, p=0.032). TBS predicted MOF and HF (but not CVF) in models adjusted for FRAX without BMD and osteoporosis treatment. TBS remained a predictor of HF (but not MOF) after further adjustment for hip BMD or spine BMD. ConclusionWe observed that spine TBS predicted MOF and HF independently of the clinical FRAX score, HF independently of FRAX and BMD in men. Studies with more incident fractures are needed to confirm these findings.

Tbs (Trabecular Bone Score) Expands Understanding of Spaceflight Effects on The Lumbar Spine of Long-Duration Astronauts

Background: Bone loss due to long-duration spaceflight has been characterized by both DXA and QCT serial scans. It is unclear if these spaceflight-induced changes in bone mineral density and structure result in increased fracture incidence. NASA astronauts currently fly on 5-6-month missions on the International Space Station (ISS) and at least one 12-month mission is planned. While NASA has measured areal BMD (by DXA) and volumetric BMD (by QCT), and has estimated hip strength (by finite element models of QCT data, no method has yet been used to examine bone microarchitecture from lumbar spine (LS). DXA scans are routinely performed pre- and post-flight on all ISS astronauts to follow BMD changes associated with space flight. Trabecular Bone Score (TBS) is a relatively new method that measures grey-scale-level texture information extracted from lumbar spine DXA images and correlates with 3D parameters of bone micro-architecture. We evaluated the ability of LS TBS to discriminate changes in astronauts who have flown on ISS missions and to determine if TBS can provide additional information compared to DXA. Methods: LS (L1-4) DXA scans from 51 astronauts (mean age, 47 +/- 4) were divided into 3 groups based on the exercise regimes performed while onboard the ISS. Pre-ARED (exercise using a load-limited resistive exercise device, <300lb), ARED (exercise with a high-load resistive exercise device, up to 600lb) and a Bisphos group (ARED exercise and a 70-mg alendronate tablet once a week before and during flight, starting 17 days before launch). DXA scans were performed and analyzed on a Hologic Discovery W using the same technician for the pre- and postflight scans. LSC for the LS in our laboratory is 0.025 g/cm2. TBS was performed at the Mercy Hospital, Cincinnati, Ohio on a similar Hologic computer. TBS precision was calculated from 16 comparable test subjects (0.0XX g/cm2). Data were preliminary analyzed using a paired, 2-tailed t-test for the difference between pre- and postflight means.

Lumbar spine texture enhances 10-year fracture probability assessment.

We found that lumbar spine texture analysis using trabecular bone score (TBS) is a risk factor for MOF and a risk factor for death in a retrospective cohort study from a large clinical registry for the province of Manitoba, Canada. FRAX® estimates the 10-year probability of major osteoporotic fracture (MOF) using clinical risk factors and femoral neck bone mineral density (BMD). Trabecular bone score (TBS), derived from texture in the spine dual X-ray absorptiometry (DXA) image, is related to bone microarchitecture and fracture risk independently of BMD. Our objective was to determine whether TBS provides information on MOF probability beyond that provided by the FRAX variables. We included 33,352 women aged 40-100years (mean 63years) with baseline DXA measurements of lumbar spine TBS and femoral neck BMD. The association between TBS, the FRAX variables, and the risk of MOF or death was examined using an extension of the Poisson regression model. During the mean of 4.7years, 1,754 women died and 1,872 sustained one or more MOF. For each standard deviation reduction in TBS, there was a 36% increase in MOF risk (HR 1.36, 95% CI 1.30-1.42, p < 0.001) and a 32% increase in death (HR 1.32, 95% CI 1.26-1.39, p < 0.001). When adjusted for significant clinical risk factors and femoral neck BMD, lumbar spine TBS was still a significant predictor of MOF (HR 1.18, 95% CI 1.12-1.23) and death (HR 1.20, 95% CI 1.14-1.26). Models for estimating MOF probability, accounting for competing mortality, showed that low TBS (10th percentile) increased risk by 1.5-1.6-fold compared with high TBS (90th percentile) across a broad range of ages and femoral neck T-scores. Lumbar spine TBS is able to predict incident MOF independent of FRAX clinical risk factors and femoral neck BMD even after accounting for the increased death hazard.

Changes in lumbar spine QCT, DXA and TBS with denosumab, alendronate or placebo in postmenopausal women with low bone mass

Searchable abstracts of presentations at key conferences on calcified tissues ISSN 2052-1219 (online)

Short-term Precision Error in Dual Energy X-Ray Absorptiometry, Bone Mineral Density and Trabecular Bone Score Measurements; and Effects of Obesity on Precision Error

Introduction: Bone mineral density (BMD) measured by dual energy x-ray absorptiometry (DXA) is the primary screening tool for diagnosis of osteopenia and osteoporosis. BMD alone does not provide information regarding the structural characteristics of bone and this limitation has been a driver for the development of techniques, including trabecular bone score (TBS) software, to assess bone microarchitecture. Precision error in DXA is important for accurately monitoring changes in BMD and it has been demonstrated that BMD precision error increases with increasing body mass index (BMI). Information on in vivo precision error for TBS is very limited. This study evaluated short-term precision error (STPE) of lumbar spine BMD & TBS measurement, and investigated the effect of obesity on DXA precision error. Method: DXA lumbar spine scans (L1-L4) were performed using GE Lunar Prodigy. STPE was measured in ninety-one women at a single visit by duplicating scans with repositioning in-between. Precision error was calculated as the percentage coefficient of variation. Participants were sub-divided into four groups based on BMI to assess the effect of obesity on STPE. Results: STPE is poorer for TBS than for BMD. STPE is adversely affected for both BMD and TBS measurements by increasing BMI but this effect is mitigated for TBS in the highest BMI category where use of the thick scanning mode improves signal to noise ratio. Conclusion: Results from serial BMD and TBS measurements should take account of differences in precision error in the two techniques and in different BMI categories.

Trabecular Bone Score: A Noninvasive Analytical Method Based Upon the DXA Image

The trabecular bone score (TBS) is a gray-level textural metric that can be extracted from the two-dimensional lumbar spine dual-energy X-ray absorptiometry (DXA) image. TBS is related to bone microarchitecture and provides skeletal information that is not captured from the standard bone mineral density (BMD) measurement. Based on experimental variograms of the projected DXA image, TBS has the potential to discern differences between DXA scans that show similar BMD measurements. An elevated TBS value correlates with better skeletal microstructure; a low TBS value correlates with weaker skeletal microstructure. Lumbar spine TBS has been evaluated in cross-sectional and longitudinal studies. The following conclusions are based upon publications reviewed in this article: 1) TBS gives lower values in postmenopausal women and in men with previous fragility fractures than their nonfractured counterparts; 2) TBS is complementary to data available by lumbar spine DXA measurements; 3) TBS results are lower in women who have sustained a fragility fracture but in whom DXA does not indicate osteoporosis or even osteopenia; 4) TBS predicts fracture risk as well as lumbar spine BMD measurements in postmenopausal women; 5) efficacious therapies for osteoporosis differ in the extent to which they influence the TBS; 6) TBS is associated with fracture risk in individuals with conditions related to reduced bone mass or bone quality. Based on these data, lumbar spine TBS holds promise as an emerging technology that could well become a valuable clinical tool in the diagnosis of osteoporosis and in fracture risk assessment.

Trabecular Bone Score Is Associated With Volumetric Bone Density and Microarchitecture as Assessed by Central QCT and HRpQCT in Chinese American and White Women

Although high-resolution peripheral quantitative computed tomography (HRpQCT) and central quantitative computed tomography (QCT) studies have shown bone structural differences between Chinese American (CH) and white (WH) women, these techniques are not readily available in the clinical setting. The trabecular bone score (TBS) estimates trabecular microarchitecture from dual-energy X-ray absorptiometry spine images. We assessed TBS in CH and WH women and investigated whether TBS is associated with QCT and HRpQCT indices. Areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry, lumbar spine (LS) TBS, QCT of the LS and hip, and HRpQCT of the radius and tibia were performed in 71 pre- (37 WH and 34 CH) and 44 postmenopausal (21 WH and 23 CH) women. TBS did not differ by race in either pre- or postmenopausal women. In the entire cohort, TBS positively correlated with LS trabecular volumetric bone mineral density (vBMD) (r = 0.664), femoral neck integral (r = 0.651), trabecular (r = 0.641) and cortical vBMD (r = 0.346), and cortical thickness (C/I; r = 0.540) by QCT (p < 0.001 for all). TBS also correlated with integral (r = 0.643), trabecular (r = 0.574) and cortical vBMD (r = 0.491), and C/I (r = 0.541) at the total hip (p < 0.001 for all). The combination of TBS and LS aBMD predicted more of the variance in QCT measures than aBMD alone. TBS was associated with all HRpQCT indices (r = 0.20–0.52) except radial cortical thickness and tibial trabecular thickness. Significant associations between TBS and measures of HRpQCT and QCT in WH and CH pre- and postmenopausal women demonstrated here suggest that TBS may be a useful adjunct to aBMD for assessing bone quality.

Assessment of women microarchitecture with and without osteoporotic fracture by TBS on white non Hispanic US women

[95% CI 1.16-1.250, P<0.001; hip fracture 1.14 [95% CI 1.05-1.23), P=0.001). Results were largely unaffected by including lumbar spine BMD or spine-hip Tscore “offset” in the model. A preliminary method to adjust FRAX probability based upon lumbar spine TBS tertile is shown in the Table. When used to reclassify fracture risk, this gave a significant increase in integrated discrimination index for MOF (+1.3%, P<0.001) and hip fracture (+1.3%, P<0.001), with net reclassification improvement +4.6% for MOF (P<0.001). There was an age interaction with larger TBS effects in younger than older women age for MOF (P<0.001) and hip fracture (P=0.002). In summary, an incremental improvement in fracture prediction was seen by using lumbar spine TBS in combination with FRAX. An approach that addresses the age-TBS interaction may be required. If validated in other prospective cohorts, lumbar spine TBS may become clinically useful for enhancing fracture prediction from FRAX.

Adjustment of FRAX probability according to lumbar spine Trabecular Bone Score (TBS): The Manitoba BMD Cohort

Adjustment of FRAX probability according to lumbar spine Trabecular Bone Score (TBS): The Manitoba BMD Cohort

Lumbar spine microarchitecture impairment evaluation in chronic kidney disease: a TBS study

Osteoporosis is a common bone disease characterized by low bone mass and altered bone microarchitecture, resulting in decreased bone strength with an increased risk of fractures. In clinical practice, physicians can assess the risk of fracture for a patient based on several risk factors. Some such as age, weight, and history of fractures after 50 years of age, parental fracture, smoking status, and alcohol intake are incorporated into FRAX, an assessment tool that estimates the 10-year probability of hip fracture and major osteoporotic fractures based on the individual's risk factors profile. The diagnosis of osteoporosis is currently based on bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry scans. Among other widely recognized limitations of BMD is that BMD considers only the density of the bone and fails in measuring bone microarchitecture, for which novel techniques, such as trabecular bone score (TBS), have been developed. TBS is a texture parameter related to bone microarchitecture that may provide skeletal information that is not captured from the standard BMD measurement. Several studies have examined the value of TBS on predicting osteoporotic fractures. Our study aimed to summarize a review of the current scientific literature with focus on fracture risk assessment and to present both its findings and its conclusions regarding how and when TBS should be used. The existing literature indicates that low lumbar spine TBS is associated with a history of fracture and the incidence of new fracture. The effect is largely independent of BMD and of sufficient magnitude to enhance risk stratification with BMD. The TBS effect is also independent of FRAX, with likely greatest utility for those individuals whose BMD levels lie close to an intervention threshold. The clinical and scientific evidence supporting the use of TBS, with the ability of this technology to be seamlessly integrated into a daily workflow, makes TBS an attractive and useful clinical tool for physicians to improve patient management in osteoporosis. Further research is ongoing and necessary to further clarify the role of TBS in additional specific disorders.

Generation and validation of a normative, age-specific reference curve for lumbar spine trabecular bone score (TBS) in French women

Age-related changes in lumbar vertebral microarchitecture are evaluated, as assessed by trabecular bone score (TBS), in a cohort of 5,942 French women. The magnitude of TBS decline between 45 and 85 years of age is piecewise linear in the spine and averaged 14.5%. TBS decline rate increases after 65 years by 50%. This study aimed to evaluate age-related changes in lumbar vertebral microarchitecture, as assessed by TBS, in a cohort of French women aged 45-85 years. An all-comers cohort of French Caucasian women was selected from two clinical centers. Data obtained from these centers were cross-calibrated for TBS and bone mineral density (BMD). BMD and TBS were evaluated at L1-L4 and for all lumbar vertebrae combined using GE-Lunar Prodigy densitometer images. Weight, height, and body mass index (BMI) also were determined. To validate our all-comers cohort, the BMD normative data of our cohort and French Prodigy data were compared. A cohort of 5,942 French women aged 45 to 85 years was created. Dual-energy X-ray absorptiometry normative data obtained for BMD from this cohort were not significantly different from French prodigy normative data (p = 0.15). TBS values at L1-L4 were poorly correlated with BMI (r = -0.17) and weight (r = -0.14) and not correlated with height. TBS values obtained for all lumbar vertebra combined (L1, L2, L3, L4) decreased with age. The magnitude of TBS decline at L1-L4 between 45 and 85 years of age was piecewise linear in the spine and averaged 14.5%, but this rate increased after 65 years by 50%. Similar results were obtained for other region of interest in the lumbar spine. As opposed to BMD, TBS was not affected by spinal osteoarthrosis. The age-specific reference curve for TBS generated here could therefore be used to help clinicians to improve osteoporosis patient management and to monitor microarchitectural changes related to treatment or other diseases in routine clinical practice.

Clinical Factors Associated With Trabecular Bone Score

Dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) is the reference standard for diagnosing osteoporosis but does not directly reflect deterioration in bone microarchitecture. The trabecular bone score (TBS), a novel grey-level texture measurement that can be extracted from DXA images, predicts osteoporotic fractures independent of BMD. Our aim was to identify clinical factors that are associated with baseline lumbar spine TBS. In total, 29,407 women ≥50yr at the time of baseline hip and spine DXA were identified from a database containing all clinical results for the Province of Manitoba, Canada. Lumbar spine TBS was derived for each spine DXA examination blinded to clinical parameters and outcomes. Multiple linear regression and logistic regression (lowest vs highest tertile) was used to define the sensitivity of TBS to other risk factors associated with osteoporosis. Only a small component of the TBS measurement (7–11%) could be explained from BMD measurements. In multiple linear regression and logistic regression models, reduced lumbar spine TBS was associated with recent glucocorticoid use, prior major fracture, rheumatoid arthritis, chronic obstructive pulmonary disease, high alcohol intake, and higher body mass index. In contrast, recent osteoporosis therapy was associated with a significantly lower likelihood for reduced TBS. Similar findings were seen after adjustment for lumbar spine or femoral neck BMD. In conclusion, lumbar spine TBS is strongly associated with many of the risk factors that are predictive of osteoporotic fractures. Further work is needed to determine whether lumbar spine TBS can replace some of the clinical risk factors currently used in fracture risk assessment.

TBS (Trabecular Bone Score) and Diabetes-Related Fracture Risk

Type 2 diabetes is associated with increased fracture risk but paradoxically greater bone mineral density (BMD). Trabecular bone score (TBS) is derived from the texture of the spine dual x-ray absorptiometry (DXA) image and is related to bone microarchitecture and fracture risk, providing information independent of BMD. This study evaluated the ability of lumbar spine TBS to account for increased fracture risk in diabetes. We performed a retrospective cohort study using BMD results from a large clinical registry for the province of Manitoba, Canada. We included 29,407 women 50 years old and older with baseline DXA examinations, among whom 2356 had diagnosed diabetes. Lumbar spine TBS was derived for each spine DXA examination blinded to clinical parameters and outcomes. Health service records were assessed for incident nontraumatic major osteoporotic fractures (mean follow-up 4.7 years). Diabetes was associated with higher BMD at all sites but lower lumbar spine TBS in unadjusted and adjusted models (all P < .001). The adjusted odds ratio (aOR) for a measurement in the lowest vs the highest tertile was less than 1 for BMD (all P < .001) but was increased for lumbar spine TBS [aOR 2.61, 95% confidence interval (CI) 2.30-2.97]. Major osteoporotic fractures were identified in 175 women (7.4%) with and 1493 (5.5%) without diabetes (P < .001). Lumbar spine TBS was a BMD-independent predictor of fracture and predicted fractures in those with diabetes (adjusted hazard ratio 1.27, 95% CI 1.10-1.46) and without diabetes (hazard ratio 1.31, 95% CI 1.24-1.38). The effect of diabetes on fracture was reduced when lumbar spine TBS was added to a prediction model but was paradoxically increased from adding BMD measurements. Lumbar spine TBS predicts osteoporotic fractures in those with diabetes, and captures a larger portion of the diabetes-associated fracture risk than BMD.

Effects of anti-resorptive agents on trabecular bone score (TBS) in older women

We evaluated the longitudinal effects of anti-resorptive agents (534 treated women vs. 1,150 untreated) on lumbar spine bone mineral density (BMD) and trabecular bone score (TBS). TBS was responsive to treatment in women over age 50. The treatment-related increase in TBS was less than the increase in BMD, which is consistent with bone texture preservation. In addition to inducing an increase in BMD, anti-resorptive agents also help to preserve bone architecture. TBS, a new gray-level texture measurement, correlates with 3D parameters of bone micro-architecture independent of BMD. Our objective was to evaluate the longitudinal effects of anti-resorptive agents on lumbar spine BMD and TBS. Women (≥ 50 years), from the BMD program database for the province of Manitoba, Canada, who had not received any anti-resorptive drug prior to their initial dual X-ray absorptiometry (DXA) exam were divided into two groups: untreated, those without any anti-resorptive drug over the course of follow-up, and treated, those with a non-estrogen anti-resorptive drug (86 % bisphosphonates, 10 % raloxifene, and 4 % calcitonin). Lumbar spine TBS was calculated for each lumbar spine DXA examination. Changes in TBS and BMD between baseline and follow-up (mean follow-up 3.7 years), expressed in percentage per year, were compared between the two groups. A total of 1,150 untreated women and 534 treated women met the inclusion criteria. Only a weak correlation was seen between BMD and TBS in either group. Significant intergroup differences in BMD change and TBS change were observed over the course of follow-up (p < 0.001). Similar mean decreases in BMD and TBS (-0.36 %/year and -0.31 %/year, respectively) were seen for untreated subjects (both p < 0.001). Conversely, treated subjects exhibited a significant mean increase in BMD (+1.86 %/year, p < 0.002) and TBS (+0.20 %/year, p < 0.001). TBS is responsive to treatment with non-estrogen anti-resorptive drug therapy in women over age 50. The treatment-related increase in TBS is less than the increase in BMD, which is consistent with bone texture preservation.

Bone microarchitecture assessed by TBS predicts osteoporotic fractures independent of bone density: The manitoba study

The measurement of BMD by dual-energy X-ray absorptiometry (DXA) is the "gold standard" for diagnosing osteoporosis but does not directly reflect deterioration in bone microarchitecture. The trabecular bone score (TBS), a novel gray-level texture measurement that can be extracted from DXA images, correlates with 3D parameters of bone microarchitecture. Our aim was to evaluate the ability of lumbar spine TBS to predict future clinical osteoporotic fractures. A total of 29,407 women 50 years of age or older at the time of baseline hip and spine DXA were identified from a database containing all clinical results for the Province of Manitoba, Canada. Health service records were assessed for the incidence of nontraumatic osteoporotic fracture codes subsequent to BMD testing (mean follow-up 4.7 years). Lumbar spine TBS was derived for each spine DXA examination blinded to clinical parameters and outcomes. Osteoporotic fractures were identified in 1668 (5.7%) women, including 439 (1.5%) spine and 293 (1.0%) hip fractures. Significantly lower spine TBS and BMD were identified in women with major osteoporotic, spine, and hip fractures (all p < 0.0001). Spine TBS and BMD predicted fractures equally well, and the combination was superior to either measurement alone (p < 0.001). Spine TBS predicts osteoporotic fractures and provides information that is independent of spine and hip BMD. Combining the TBS trabecular texture index with BMD incrementally improves fracture prediction in postmenopausal women.