Spine Dual-energy X-ray Absorptiometry Research Articles

The utility and limitations of using trabecular bone score with FRAX.

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

Aortic vascular calcification is inversely associated with the trabecular bone score in patients receiving dialysis.

Progressive chronic kidney disease (CKD) confers a marked increase in risk for vascular calcification, cardiovascular disease, fracture and mortality, with likely contributing factors including dysregulated bone metabolism and mineral homeostasis. In general population studies, increased vascular calcification is directly related to mortality and inversely related to bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA). In patients with CKD, abnormalities in turnover, mineralization and bone volume reduce the ability of DXA to predict fracture. The trabecular bone score (TBS) obtained from lumbar spine DXA images, provides a surrogate measure of microarchitectural integrity not captured by BMD. This study aimed to examine the association of the TBS to prevalent abdominal aortic calcification (AAC) in patients with CKD receiving dialysis. We performed a cross-sectional study of dialysis patients awaiting transplantation. All patients underwent laboratory testing, lateral spinal radiographs including the abdominal aorta, DXA imaging and TBS assessment. AAC scores were determined using the Kauppila method. Correlations and linear regression models were used to determine predictors of AAC scores. 146 patients (60% male, mean age 48 ± 13 years) were included, of whom 49% had prevalent calcification with an AAC score ≥ 1. Of those with calcification, the mean AAC score was 7 ± 5.5 and 42 patients had scores ≥ 6, considered to indicate severe AAC. TBS values corresponding to intermediate or high risk for fracture (<1.31) were present in 35% of patients. TBS values correlated inversely to AAC scores (β = -0.206, p = 0.013) and remained significant in multivariable linear regression, adjusting for age, BMI and time on dialysis (-0.160, p = 0.031). There was no significant correlation of AAC scores to any BMD parameter. There is a high prevalence of AAC in relatively young dialysis patients awaiting transplantation and their AAC scores are inversely related to the TBS but not to DXA-derived BMD parameters. In patients with CKD on dialysis, TBS assessment reflects microarchitectural abnormalities of bone not captured by DXA. The inverse relationship of TBS to vascular calcification may provide insights into bone-vascular interactions in CKD.

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

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

Association between vitamin D level and patients with cholestasis

Background: Estimate the prevalence of vitamin D deficiency among patients diagnosed with chronic cholestasis and investigates the association between their clinical manifestations and lab results of 25(OH) D levels.Methods: A cross sectional study of 50 patients aged &gt; 3 months up to 18 years, who had medical care in the Beni-Suef University hospital, Beni-Suef governorate, Egypt. All patients were fully investigated including routine labs in addition to 25- [OH] D levels and dual energy X-ray absorptiometry (DXA).Results: Mean age was 6.5±4.5 years. Mean serum 25 (OH) D levels was 37.9±28.2; 30% of patients had 25 (OH) D &lt;20 ng/ml and 26% had 25 (OH) D 20-&lt;30 ng/ml. Low BMD was diagnosed in 73.1% of patients. The spine DXA BMD ranged between -5.4 and -1.4 (-2.9±0.9 Z-scores). A delayed milestone was reported in 32% of patients, and 56% had signs of rickets.Conclusions: Deficiency of Vitamin D, signs of rickets and osteoporosis were evident in chronic cholestasis patients. No statistical significance was detected between 25- D [OH] levels and clinical, laboratory and radiological findings.

The trabecular bone score is associated with bone mineral density, markers of bone turnover and prevalent fracture in patients with end stage kidney disease.

Declining renal function carries increased fracture risks, but BMD is less predictive of fracture for dialysis patients than the general population. The TBS, obtained from lumbar spine dual-energy X-ray absorptiometry (DXA) images, provides information on microarchitectural integrity not captured by BMD. The aim of this study was to assess associations of the TBS to clinical, DXA, radiological, and laboratory measures in patients with ESKD undergoing kidney and simultaneous pancreas kidney (SPK) transplantation. A total of 147 patients with ESKD underwent pre-transplant laboratory testing, DXA, lateral spine X-ray, and structured history within 4weeks of transplantation. Associations of the TBS to demographic data, prevalent fracture, BMD, and laboratory variables were assessed. Of 147 patients (60% male, mean age 48±13years), 36% had diabetes mellitus (DM) and 54 patients had fractures: 21 prevalent vertebral fractures only, 22 non-vertebral fractures only, and 11 had both. The mean TBS (1.345±0.125) was lower in patients undergoing SPK than kidney-only transplants (1.292 vs. 1.364, p=0.001). The TBS correlated to spine and total hip BMD, body mass index and inversely to parathyroid hormone, alkaline phosphatase and procollagen 1 N-propeptide. By multivariable logistic regression, lower TBS was significantly associated to prior non-vertebral fracture (p=0.026). A lower TBS, suggestive of increased microarchitectural damage, was associated with type 1 DM, markers of higher bone turnover, and prevalent fracture. These data support the need for prospective studies to evaluate whether TBS inclusion improves fracture prediction in patients with ESKD.

Effects of Gastric Bypass Surgery on Bone Mass and Microarchitecture Occur Early and Particularly Impact Postmenopausal Women.

Roux-en-Y gastric bypass (RYGB) surgery is a highly effective treatment for obesity but negatively affects the skeleton. Studies of skeletal effects have generally examined areal bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), but DXA may be inaccurate in the setting of marked weight loss. Further, as a result of modestly sized samples of mostly premenopausal women and very few men, effects of RYGB by sex and menopausal status are unknown. We prospectively studied the effects of RYGB on skeletal health, including axial and appendicular volumetric BMD and appendicular bone microarchitecture and estimated strength. Obese adults (N = 48; 27 premenopausal and 11 postmenopausal women, 10 men) with mean ± SD body mass index (BMI) 44 ± 7 kg/m2 were assessed before and 6 and 12 months after RYGB. Participants underwent spine and hip DXA, spine QCT, radius and tibia HR-pQCT, and laboratory evaluation. Mean 12-month weight loss was 37 kg (30% of preoperative weight). Overall median 12-month increase in serum collagen type I C-telopeptide (CTx) was 278% (p < 0.0001), with greater increases in postmenopausal than premenopausal women (p = 0.049). Femoral neck BMD by DXA decreased by mean 5.0% and 8.0% over 6 and 12 months (p < 0.0001). Spinal BMD by QCT decreased by mean 6.6% and 8.1% (p < 0.0001); declines were larger among postmenopausal than premenopausal women (11.6% versus 6.0% at 12 months, p = 0.02). Radial and tibial BMD and estimated strength by HR-pQCT declined. At the tibia, detrimental changes in trabecular microarchitecture were apparent at 6 and 12 months. Cortical porosity increased at the radius and tibia, with more dramatic 12-month increases among postmenopausal than premenopausal women or men at the tibia (51.4% versus 18.3% versus 3.0%, p < 0.01 between groups). In conclusion, detrimental effects of RYGB on axial and appendicular bone mass and microarchitecture are detectable as early as 6 months postoperatively. Postmenopausal women are at highest risk for skeletal consequences and may warrant targeted screening or interventions. © 2017 American Society for Bone and Mineral Research.

Model for improved correlation of BMD values between abdominal routine Dual energy CT data and DXA scans

BackgroundOsteoporosis is a common but underdiagnosed and undertreated disease causing severe morbidity and economic burden. The gold standard for detection of osteoporosis is DXA (dual energy x-ray absorptiometry), which is a dedicated examination for osteoporosis. Dual energy CT (DECT) examinations are increasingly used in daily routine for a wide variety of diagnoses. In the present study, we wanted to examine whether vBMD (volume bone mass density) could be evaluated as a side product in non-contrast as well as contrast phases as well as to evaluate a correction model taking known shortcomings for DXA into account. MethodsA total of 20 patients, i.e. 79 vertebrae (one excluded due to vertebral fracture), mean age 71 years (range 43–85) with a mean BMI (body mass index) of 26 (range 17–33) were examined with both abdominal/pelvic DECT as well as DXA. Furthermore, aortic calcium was measured as well as the presence of osteoarthritis of the spine (OAS) and osteoarthritis in facet joints (OAF) with a 5-grade scaling system. ResultsA significant correlation was found between DXA BMD and vBMD from DECT with no contrast (WNC) (r = 0.424, p = 0.001), and with venous contrast (WVC) (r = 0.402, p < 0.001), but no significant correlation was found with arterial contrast (WAC). Using multivariate linear regression with DXA BMD as dependent, two models were created combining DECT WNC, aortic calciumscore (ACS), OAS and BMI yielding an R2 = 0.616 (model 1) and replacement of WNC to WVC a R2 = 0.612 (model 2). The Pearson correlation between DXA and predictive DXA BMD value of model 1 was r = 0.785 (p < 0.001) and model 2 r = 0.782 (p < 0.001). ConclusionThere is a correlation between DXA BMD and DECT in non-contrast and venous contrast scans but not in arterial scans. The correlation is further improved by quantifying the degree of different confounding factors (osteoarthritis of the spine, body mass index and aortic calcium score) and taking these into account in an explanatory model. Future software solutions with DECT data as input data might be able to automatically measure the BMD in the trabecular bone as well as measuring the confounding factors automatically in order to obtain spinal DXA comparable BMD values.

THE CURRENT ISSUES ON OSTEOPOROSIS AMONG MALE SAUDI ARABIANS

Background and Objectives Osteoporosis was reported to be common among the Saudi Arabian population. In the last decade there have been no reports related to the male osteoporosis in Saudi Arabian citizens. The objective of this study was to find the hospital-based prevalence of male osteoporosis and the associated diseases. Methodology This is a retrospective study between January 2014 and December 2016 in which all patients who were referred for DEXA (Dual Energy X-ray Absorptiometry) scan to the radiology department of the King Fahd Hospital of the University, AlKhobar were included. Patient’s demographic data were collected from the medical records. Patients who were younger than 50 and those who had a fragility fracture were excluded from the analysis. From the Picture Archiving and Communication System (PACS, Siemens AG, Erlangen, Germany) the readings of the DEXA were collected. Associated diseases of the patients were also extracted from the QuadruMed Data Base. The data was entered in the database and analyzed using SPSS Inc. version 19 and p value of <0.05 was considered significant. Results Four hundred and fifty-five patients had a DEXA scan during the study period. Three hundred and seventy- one (81.5%) were ≥50 years. The average was 65.33±9.85 years (range 50–97). On the basis of Spinal T score, 222 (59.8%) were osteoporotic with the Spinal T score of <−3.58±0.88, while, with Hip T score 120 (32.3%) were osteoporotic with T score of <−3.24±0.59. Thirty-six (9.7%) had a normal DEXA of spine and 74(19.9%) of patients had normal DEXA when the Hip T score was taken into consideration. Patients could be divided into 4 groups based on their diseases; they were on treatment for cardiac disease 106 (28.5%), Diabetes mellitus 95 (25.7%), osteoarthritis 141 (38%) and respiratory disease 29 (7.8%). Based on the Spinal T score osteoporosis was observed in 61/106 (57.5%) patients with cardiac disease, 62/95 (65.3%) in diabetics, in osteoarthritis 83/141 (58.9%) and 16/29 (55.1%) in patients with respiratory system diseases. Majority of the patients had vitamin D3 analysis and were most of the patients were in the deficiency range. From 222 (59.83%) patients who were diagnosed to have osteoporosis only 108 (48.64%) were on appropriate treatment for osteoporosis. Conclusion This study finds that the prevalence of osteoporosis in Saudi Arabian males is higher than in the western world and has increased in the last decade. The authors believe a more determined effort is needed to lower the screening age for osteoporosis and report the observations. This will allow a consensus to be reached regarding the frequency of osteoporosis in Saudi Arabian males and implement appropriate measures to limit its growth.

Lumbar computed tomography scans are not appropriate surrogates for bone mineral density scans in primary adult spinal deformity.

OBJECTIVE The authors examined the correlation between lumbar spine CT Hounsfield unit (HU) measurements and bone mineral density measurements in an adult spinal deformity (ASD) population. METHODS Patients with ASD were identified in the records of a single institution. Lumbar CT scans were reviewed, and the mean HU measurements from L1-4 were recorded. Bone mineral density (BMD) was assessed using femoral neck and lumbar spine dual-energy x-ray absorptiometry (DEXA). The number of patients who met criteria for osteoporosis was determined for each imaging modality. RESULTS Forty-eight patients underwent both preoperative DEXA and CT scanning. Forty-three patients were female and 5 were male. Forty-seven patients were Caucasian and one was African American. The mean age of the patients was 62.1 years. Femoral neck DEXA was more likely to identify osteopenia (n = 26) than lumbar spine DEXA (n = 8) or lumbar CT HU measurements (n = 6) (p < 0.001). There was a low-moderate correlation between lumbar spine CT and lumbar spine DEXA (r = 0.463, p < 0.001), and there was poor correlation between lumbar spine CT and femoral neck DEXA (r = 0.303, p = 0.036). CONCLUSIONS Despite the opportunistic utility of lumbar spine CT HU measurements in identifying osteoporosis in patients undergoing single-level fusion, these measurements were not useful in this cohort of ASD patients. The correlation between femoral neck DEXA and HU measurements was poor. DEXA assessment of BMD in ASD patients is essential to optimize the care of these complicated cases.

The Prediction of Body Composition in African Americans From Spine and Hip Dual-Energy Absorptiometry

Body composition, the makeup of the body's fat and lean tissue, is associated with important health outcomes and provides useful clinical information. Although body composition can be measured with total body dual-energy X-ray absorptiometry (DXA), this is rarely performed. As an alternative to total body DXA measurement, methods for estimation of body composition have been developed. These methods use soft tissue measures from spine and hip DXA to predict body composition and include prediction equations previously published by Leslie and proprietary equations within General Electric densitometry software. However, these estimates have not been tested in African Americans (AA), an ethnicity with a different distribution of fat than Caucasians (CA). Therefore, we examined the performance of the existing models in 99 CA and 162 AA subjects over the age of 40 who had total body, spine, and hip DXA measurements. We observed that existing models estimated body composition well in CA but underestimated fat mass and overestimated lean mass in AA. AA subjects were then randomly divided into 2 equal-sized subgroups—the first to develop new prediction equations and the second to independently validate them. We found that body composition can be more accurately estimated using either a new model that we derived in AA subjects using backward stepwise elimination or by adding a fixed offset for AA to the previously published model. Our results demonstrate that body composition estimates from spine and hip DXA require consideration of race/ethnicity.

Effects of clinical reanalysis in dual energy X-ray absorptiometry reports.

This study aims to assess poor positioning rates of patients during X-ray and the accuracy of the analysis. In this study, we reanalyzed 323 dual energy X-ray absorptiometry (DXA) reports, by evaluating the scan images for proper patient positioning and scan analysis. We reviewed reports, according to a checklist prepared considering the proposals of Watts and The International Society for Clinical Densitometry official positions for 2013 (which were the same as in 2015). At least two remaining vertebrae were used to derive new bone mineral density and new T-scores. Positioning failures were found in 64.7% of the spine X-rays, 60.5% of the hip X-rays, and 83.9% of X-rays of both regions. A total of 112 (34.7%) spinal DXA images needed new T-score adjustments. T-scores and bone mineral density differed between the first reports and the clinician reanalysis (p<0.001). The error rate in DXA reports was higher than expected. Clinician analysis of DXA reports are important. To obtain a quality DXA report, all healthcare professionals should be trained and reminded about this topic.

Maternal vitamin D and offspring trabecular bone score.

Trabecular bone score (TBS), a novel tool derived from dual-energy X-ray absorptiometry (DXA), reflects the microarchitecture of the vertebrae. It has been shown to predict fracture independent of standard DXA parameters in adult populations. Previously, we demonstrated that maternal serum 25-hydroxyvitamin D (25(OH)D) during pregnancy is associated with offspring bone mineral content at age 11years. However, associations with TBS have not been explored, thus we aimed to determine associations between maternal 25(OH)D and offspring TBS. Data were collected from the Vitamin D in Pregnancy (VIP) study. Venous blood samples were taken at recruitment and at 28-32weeks' gestation. Maternal 25(OH)D was measured by radioimmunoassay. Offspring (n=195, n=181 with complete measures) underwent spine DXA (GE Lunar), at age 11years (median=10.9 (IQR 10.9-11.4)). TBS was calculated using TBS iNsight software. Offspring of mothers with sufficient 25(OH)D levels (≥50nmol/L) at recruitment had a higher TBS (1.363 vs. 1.340, p=0.04). In multivariable linear regression models, after adjustment for child relative lean mass, sex and pubertal stage, a 10nmol/L increase in maternal 25(OH)D was associated with a 0.005 (95% CI 0.000, 0.010, p=0.04) increase in TBS. However when stratified by sex (p for interaction=0.16), the association was significant in boys, but not girls. There were no associations with TBS and maternal 25(OH)D at 28-32weeks. We speculate that maternal 25(OH)D in early pregnancy may be associated with TBS in offspring at age 11 in boys. These hypothesis-generating findings warrant confirmation with larger interventional and long-term follow-up studies.

The main autoimmune and nonautoimmune etiologies of endogenous hyperthyroidism do not seem to influence the increased prevalence of morphometric vertebral fractures and osteoporosis in Portuguese men

ObjectivesThe purpose of this study was to evaluate the effects of hyperthyroidism and their etiology on bone mineral density (BMD), on body soft tissue composition, on the prevalence of vertebral fractures detected by vertebral fracture assessment (VFA) and on the trabecular bone score (TBS). MethodsFrom an initial population of 119 Portuguese men (78 with hyperthyroidism [HT]+ 41 controls [CTs]) admitted to the Endocrinology Department we selected 41 men aged over 50 with clinical hyperthyroidism to participate; each one was matched by age and height with a control person. BMD (g/cm2) at the lumbar spine, hip, radius 33% and whole body and the total body masses (kg) were studied by dual-energy X-ray absorptiometry (DXA). VFA with Genant semiquantitative method was used to detect fractures. The TBS was obtained from lumbar spine DXA images. No patient had been treated previously for hyperthyroidism or osteoporosis. Adequate statistical tests were used. ResultsIn the hyperthyroidism group, total lean mass (CT 58.16 ± 7.7 vs. HT 52.3 ± 5.7, P = 0.03) and distal radius BMD (CT 0.769 ± 0.05 vs. HT 0.722 ± 0.08, P = 0.005) were lower; there was a significantly higher prevalence of osteoporosis (CT 9.7% vs. HT 29.3%, P = 0.015) and vertebral fractures (CT 2.4% vs. HT 24.4%, P = 0.007). TBS was similar in both groups (CT 1.328 ± 0.11 vs. HT 1.356 ± 0.11, P = not significant). Comparing patients with Graves' disease with patients with toxic goiter, there were no differences regarding BMD, BMD qualification, prevalence of fractures and TBS and just total lean mass was significantly lower in patients with Graves' disease. ConclusionsThese results suggest that in a group of hyperthyroid men aged over 50 there are significant decreases in cortical bone BMD and lean mass and a higher prevalence of osteoporosis and silent vertebral fractures, but the etiology of the hyperthyroidism does not seem to influence it. Besides the antithyroid drugs, some patients may benefit from bone-directed treatments.

Evaluation and Management of Primary Ovarian Insufficiency in Adolescents and Young Adults

Study ObjectiveTo identify clinical features associated with primary ovarian insufficiency (POI) and collect data on the evaluation and treatment received. DesignRetrospective chart review. Data were abstracted on etiology of POI, history, laboratory evaluation, imaging results, return for clinical care, and treatment plans. SettingUrban children's hospital in Cincinnati, Ohio. ParticipantsFifty female patients, age 11-26 years, with initial presentation of POI between January 1, 2006 and December 31, 2015. Main Outcome MeasuresEtiology of POI, bone mineral density (BMD), laboratory evaluation, and services utilized at presentation. ResultsThree hundred thirty-one charts were reviewed, 71 with confirmed diagnosis of POI, and 50 with sufficient data for inclusion. Among the 50, 21 (42%) had Turner syndrome, 18 (36%) remained idiopathic, and 11 (22%) had another condition (eg, autoimmune polyglandular syndrome, galactosemia, etc). Thirty-six (72%) were karyotyped; in 14 (28%), 21-hydroxylase antibodies were measured; 32 (64%) underwent dual-energy x-ray absorptiometry BMD measures of lumbar spine. Eight of 50 patients (16%) reported fracture. Of these, at presentation, 4 (50%) had low BMD, and 2 (25%) had slightly low BMD. On initial spinal dual-energy x-ray absorptiometry, 9 of 32 (28%) had low BMD (Z-score ≤ −2.0) and 7 of 32 (22%) were slightly low (−1.0 to −1.9). All started estrogen therapy within 2 years of presentation. In follow-up, only 2 patients (4%) saw a mental health consultant for emotional support. ConclusionPOI is a model of estrogen deficiency with most cases due to Turner syndrome or idiopathic causes. At presentation, many had low BMD and few were seen for psychological support as part of multidisciplinary care.

Dual-Energy X-ray Absorptiometry Predictors of Vertebral Deformities in Beta-Thalassemia Major

Vertebral fractures in beta-thalassemia major are increasingly found because of the longer life expectancy of patients, with a major negative impact on their quality of life. We performed a retrospective cross-sectional study to investigate the prevalence of vertebral deformities in thalassemic patients and to identify their best dual-energy X-ray absorptiometry (DXA) predictor among trabecular bone score (TBS), bone mineral density (BMD), and Z-score. Eighty-two outpatients with beta-thalassemia major on regular conventional treatment were studied at a single academic center. All patients underwent plain thoracic-lumbar spine X-rays and lumbar DXA to assess the number and the severity of vertebral deformities (Genant's method), the spinal deformity index, lumbar spine DXA parameters (BMD, TBS, and Z-score), and the presence of platyspondyly. Twenty-nine patients (35%) had vertebral deformities and showed significantly lower TBSs than the remainders (1.141 ± 0.083 vs 1.254 ± 0.072, p < 0.0001). The analysis of variance of the TBS between the group of patients without vertebral deformities (spinal deformity index = 0) and the remaining groups showed a significant difference (p < 0.001). The TBS had better sensitivity (86.2%), specificity (75.5%), and diagnostic accuracy (79.3%) than BMD and Z-score in discriminating patients with and without vertebral deformities. Combining the TBS with the BMD or the Z-score showed that the diagnostic accuracy of the first in discriminating patients with and without vertebral deformities improved from 79.3% to 85.4% and 87.8%, respectively. The presence of platyspondyly was a significant predictor of vertebral deformities in the multivariate model. Vertebral deformities in well-treated patients with beta-thalassemia major are common and are often unrecognized. In our hands, the TBS was better than the BMD and the Z-score in predicting vertebral deformities. Plain X-rays of the spine should be performed also in asymptomatic patients, especially when the TBS is low.

Effect of denosumab on trabecular bone score in postmenopausal women with osteoporosis.

TBS, a gray-level texture index determined from lumbar spine DXA scans, correlates with bone microarchitecture and enhances assessment of vertebral fracture risk independently of BMD. In the FREEDOM study, denosumab increased BMD and reduced new vertebral fractures in postmenopausal women with osteoporosis. This retrospective analysis explored the effect of denosumab on TBS and the association between TBS and BMD in FREEDOM. Postmenopausal women with lumbar spine or total hip BMD T-score <-2.5 and -4.0 or higher at both sites received placebo or denosumab 60mg subcutaneously every 6months. TBS indices were determined from DXA scans at baseline and months 12, 24, and 36 in a subset of 285 women (128 placebo, 157 denosumab) who had TBS values at baseline and ≥1 postbaseline visit. Baseline characteristics were comparable between treatment groups; mean (SD) lumbar spine BMD T-score was -2.79 (0.64), and mean (standard deviation [SD]) TBS was 1.200 (0.101) overall. In the placebo group, BMD and TBS increased by ≤0.2% or decreased from baseline at each visit. In the denosumab group, progressive increases from baseline at 12, 24, and 36months were observed for BMD (5.7, 7.8, and 9.8%) and TBS (1.4, 1.9, and 2.4%). Percentage changes in TBS were statistically significant compared with baseline (p<0.001) and placebo (p≤0.014). TBS was largely unrelated to BMD, regardless of treatment, either at baseline or for annual changes from baseline (all r 2≤0.06). In postmenopausal women with osteoporosis, denosumab significantly improved TBS independently of BMD.

Effects of Teriparatide, Denosumab, or Both on Spine Trabecular Microarchitecture in DATA-Switch: a Randomized Controlled Trial

In postmenopausal women, 2 yr of combined teriparatide and denosumab increases bone mineral density more than either drug alone, and switching from either combination or teriparatide to denosumab for an additional 2 yr further increases bone mineral density. Conversely, switching from denosumab to teriparatide results in transient bone loss. The effects of these interventions on spine microarchitecture are unknown. In the DATA and DATA-Switch studies, 94 postmenopausal osteoporotic women were randomized to receive 24 mo of teriparatide (20 µg daily), denosumab (60 mg every 6 mo), or both. Then, women originally assigned to 24 mo of teriparatide received 24 mo of denosumab, whereas subjects originally randomized to 24 mo of denosumab received 24 mo of teriparatide. Subjects who received both drugs received an additional 24 mo of denosumab alone. Spine trabecular bone score (TBS, a gray-level textural assessment of bone microarchitecture) was measured blinded from treatment groups using images from 2-dimensional dual-energy X-ray absorptiometry spine scans at 0, 12, 24, 30, 36, and 48 mo in 65 women who had posterior-anterior spine dual-energy X-ray absorptiometry images suitable for TBS analysis. After 24 mo, TBS increased by 2.7 ± 4.7% in the teriparatide group (p = 0.009 vs baseline), by 1.8 ± 5.0% in the denosumab group (p = 0.118 vs baseline), and by 4.5 ± 6.7% in the combination group (p = 0.017 vs baseline), with no significant between-group differences. In the 6 mo after the treatments were switched (months 24–30), TBS continued to increase in the combination-to-denosumab and teriparatide-to-denosumab groups but decreased by −1.1 ± 4.0% in the denosumab-to-teriparatide group (p < 0.05 vs other groups). After 48 mo, compared to month 0, TBS increased by 5.1 ± 5.8% in the teriparatide-to-denosumab group, by 3.6 ± 4.2% in the denosumab-to-teriparatide group, and by 6.1 ± 4.7% in the combination-to-denosumab group (p < 0.001 vs baseline for all groups, p = not significant for between-group differences). Switching from teriparatide to denosumab also increased spine TBS. Conversely, switching from denosumab to teriparatide transiently degraded spine trabecular microarchitecture, the clinical consequences of which require further study.

Association of Trabecular Bone Score (TBS) With Incident Clinical and Radiographic Vertebral Fractures Adjusted for Lumbar Spine BMD in Older Men: A Prospective Cohort Study

The association of trabecular bone score (TBS) with incident clinical and radiographic vertebral fractures in older men is uncertain. TBS was estimated from baseline spine dual-energy X-ray absorptiometry (DXA) scans for 5831 older men (mean age 73.7 years) enrolled in the Osteoporotic Fractures in Men (MrOS) study. Cox proportional hazard models were used to determine the association of TBS (per 1 SD decrease) with incident clinical vertebral fractures. Logistic regression was used to determine the association between TBS (per 1 SD decrease) and incident radiographic vertebral fracture among the subset of 4309 men with baseline and follow-up lateral spine radiographs (mean 4.6 years later). We also examined whether any associations varied by body mass index (BMI) category. TBS was associated with a 1.41-fold (95% confidence interval [CI] 1.23 to 1.63) higher aged-adjusted odds of incident radiographic fracture, and this relationship did not vary by BMI (p value = 0.22 for interaction term). This association was no longer significant with further adjustment for lumbar spine bone mineral density (BMD; odds ratio [OR] = 1.11, 95% CI 0.94 to 1.30). In contrast, the age-adjusted association of TBS with incident clinical vertebral fracture was stronger in men with lower BMI (≤ median value of 26.8 kg/m2 ; hazard ratio [HR] = 2.28, 95% CI 1.82 to 2.87) than in men with higher BMI (> median; HR = 1.60, 95% CI 1.31 to 1.94; p value = 0.0002 for interaction term). With further adjustment for lumbar spine BMD, the association of TBS with incident clinical vertebral fracture was substantially attenuated in both groups (HR = 1.30 [95% CI 0.99 to 1.72] among men with lower BMI and 1.11 [95% CI 0.87 to 1.41] among men with higher BMI). In conclusion, TBS is not associated with incident clinical or radiographic vertebral fracture after consideration of age and lumbar spine BMD, with the possible exception of incident clinical vertebral fracture among men with lower BMI. © 2017 American Society for Bone and Mineral Research.

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

Decreased lumbar spine trabecular bone score (TBS), a dual-energy X-ray absorptiometry (DXA)-derived image texture measurement, is a risk factor for major osteoporotic fracture (MOF) and hip fracture (HF) independent of 10-year fracture probability estimated using FRAX. We determined how often applying the TBS adjustment to fracture probability altered treatment qualification. Using a population-based registry containing all clinical DXA results for Manitoba, Canada, we identified 34,316 women with baseline spine and hip DXA, FRAX-based fracture probability measurements (computed with femoral neck bone mineral density), lumbar spine TBS, and minimum 5 years of observation (mean 8.7 years). Population-based health services data were used to identify incident non-traumatic MOF and HF in 3503 and 945 women, respectively. Baseline MOF and HF probabilities were estimated using FRAX before and after applying the TBS adjustment. Risk recategorization was assessed using net reclassification improvement (NRI) for individual FRAX-based intervention criteria and three national clinical practice guidelines (CPGs) (US National Osteoporosis Foundation, Osteoporosis Canada, and UK National Osteoporosis Guideline Group). Overall, proportions of women reclassified with the TBS adjustment to FRAX were small (less than 5%) with more than 90% of the reclassification occurring close to the intervention threshold. For women close to an intervention cut-off reclassification, rates ranged from 9.0% to 17.9% and were <1% otherwise. There was a small but significant improvement in overall NRI for all individual FRAX-based intervention criteria (range 0.007 to 0.018) and all three national CPGs (range 0.008 to 0.011). NRI was larger in women below age 65 years (up to 0.056 for hip fracture). In summary, a small but significant improvement in MOF and HF risk assessment was found by using lumbar spine TBS to adjust FRAX probability. An improvement in risk reclassification was observed for CPGs from three different countries, with almost all of the benefit found in individuals close to an intervention threshold. © 2017 American Society for Bone and Mineral Research. © 2017 American Society for Bone and Mineral Research.

Use of dual energy X‐ray absorptiometry, the trabecular bone score and quantitative computed tomography in the evaluation of chronic kidney disease‐mineral and bone disorders

In subjects with chronic kidney disease (CKD) who suffer a minimal trauma fracture, the problem is to differentiate between osteoporosis and the various forms of renal bone disease associated with CKD-mineral and bone disorder. This problem is exacerbated by the fact that renal osteodystrophy may coexist with osteoporosis. The World Health Organization's bone mineral density (BMD) criteria for osteopenia ( -2.5<T-score<-1.0) and osteoporosis (a T-score≤-2.5) may be used in patients with CKD stages 1-3. In CKD stages 4-5, BMD by dual-energy X-ray absorptiometry (DXA) is less predictive and may underestimate fracture risk. The development of absolute fracture risk (AFR) algorithms, such as FRAX® and the Garvan absolute fracture risk calculator, to predict risk of fracture over a given time (usually 10years) aims to incorporate non-BMD risk factors into the clinical assessment. FRAX® has been shown to be useful to assess fracture risk in CKD but may underestimate fracture risk in advanced CKD. The trabecular bone score is a measure of grey scale homogeneity obtained from spine DXA, which correlates to trabecular microarchitecture and is an independent risk factor for fracture. Recent data demonstrate the potential utility of the trabecular bone score adjustment of AFR through the FRAX® algorithm in subjects with CKD. Parameters of bone microarchitecture using peripheral quantitative computed tomography (pQCT) or high-resolution pQCT are also able to discriminate fracture status in subjects with CKD. However, there are at present no convincing data that the addition of pQCT or high-resolution pQCT parameters to DXA BMD improves fracture discrimination. More advanced estimates of bone strength derived from measurements of micro-architecture, by QCT-derived finite element analysis may be incorporated into AFR algorithms in the future.