Association between trabecular bone score and risk factors for fractures in Korean female patients with rheumatoid arthritis

Association between trabecular bone score, 10-year probability risk for fracture, and vertebral fractures in rheumatoid arthritis

Objectives

The aim was to assess the association and predictive value of trabecular bone score (TBS), fracture risk assessment tool (FRAX), and TBS-adjusted FRAX with prevalent vertebral fractures (VFs) in patients with rheumatoid arthritis (RA).

Methods

Patients diagnosed with RA were included in this cross-sectional study. Clinical data and laboratory tests were collected on the same day as the dual-energy x-ray absorptiometry (DXA) scan. TBS, bone mineral density (BMD), and vertebral fracture assessment (VFA) were obtained from the DXA scan. We used the FRAX tool to assess the 10-year probability of major osteoporotic fracture (MOF-FRAX) and hip fracture (HF-FRAX) with and without BMD. These parameters were further adjusted for TBS. Patients with prevalent VFs were defined as those with moderate to severe VFs from T4 to L4. VFs presence was used as the binary variable in the logistic regressions and receiving operator characteristics (ROC) curves analysis.

Results

Sixty-nine patients were enrolled, with 55.1 % being postmenopausal. The mean TBS was 1.328 ± 0.104. Osteoporosis according to the WHO criteria was present in 39 patients (56.5 %), and six patients (8.7 %) had VFs with thoracic predominance (66.67 %). Univariate and multivariate logistic regression analyses did not show an association between TBS and vertebral fractures, but FRAX scores indicated such an association. The area under the curve (AUC) with 95 % confidence intervals (CI) for the MOF-FRAX score with BMD, MOF-FRAX score without BMD, TBS-adjusted MOF-FRAX score, and TBS were 0.837 [0.686-0.988], 0.795 [0.629-0.961], 0.778 [0.571-0.984], and 0.515 [0.298-0.731], respectively.

Conclusion

In our RA patients, FRAX scores were associated with vertebral fractures (VFs), while TBS was not. The MOF-FRAX score combined with BMD, showed the best AUC for VFs in this population.

Damaged bone microarchitecture by Trabecular Bone Score (TBS) and low appendicular muscle mass: main risk factors for vertebral and non-vertebral fractures in women with long-standing rheumatoid arthritis

We ascertained the fracture risk factors stratified by vertebral and non-vertebral sites in rheumatoid arthritis (RA) females. Bone/muscle features, but not disease activity, were the main markers for fractures in this long-standing RA population: low trabecular bone score (TBS) for vertebral fracture and decreased appendicular muscle mass for non-vertebral fracture.

PURPOSE

To assess risk factors for fractures, including clinical, laboratory and dual energy X-ray absorptiometry (DXA) parameters (bone mass, trabecular bone score-TBS, muscle mass) in women with established rheumatoid arthritis (RA).

METHODS

Three hundred females with RA (ACR, 2010) were studied. Clinical data were obtained by questionnaire and disease activity by composite indices (DAS28, CDAI, SDAI), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Bone mineral density (BMD), TBS, body composition and Vertebral Fracture Assessment (VFA) were performed by DXA. Logistic regression models were constructed to identify factors independently associated with vertebral (VF) and non-vertebral fractures (NVF), separately.

RESULTS

Through rigorous eligibility criteria, a total of 265 women were yielded for final data analysis (median age, 55 [22-86] years; mean disease duration, 16.2 years). Prevalence of VF and NVF were 30.6% and 17.4%, respectively. In multivariate analyzes, TBS (OR = 1.6, 95%CI = 1.09-2.36, p = 0.017), CRP (OR = 1.54, 95%CI = 1.15-2.08, p = 0.004), and parathormone (OR = 1.24, 95%CI = 1.05-1.45, p = 0.009) were risk factors for VF, whereas low appendicular muscle mass (OR = 2.71; 95%CI = 1.01-7,28; p = 0.048), body mass index (BMI) (OR = 0.90, 95%CI = 0.82-0.99; p = 0.025), ESR (OR = 1.18, 95%CI = 1.01-1,38, p = 0,038) and hip BMD (OR = 1.82, 95%CI = 1.10-3.03, p = 0.02) were associated with NVF.

CONCLUSION

In women with long-term RA, markers of fractures differed between distinct skeletal sites (vertebral and non-vertebral). The magnitude of association of bone/muscle parameters with fracture (TBS for VF and appendicular muscle mass for NVF) was greater than that of the association between RA activity and fracture. TBS seems to have greater discriminative power than BMD to identify subjects with VF in long-standing RA.

Correlation between Trabecular Bone Score and Homocysteine Level in Rheumatoid Arthritis Patients on Anti-TNF Inhibitors

Rheumatoid arthritis (RA) is an independent osteoporosis risk factor. Biologic and immunosuppressive treatment, and levels of homocysteine and 25-OH vitamin D may influence the trabecular bone score (TBS) in RA patients. We aimed to compare the effects of biological (b) and conventional synthetic (cs) disease-modifying anti-rheumatic drugs (DMARDs) on TBS in patients with RA and hyperhomocysteinemia (HHcy) or 25-OH vitamin D deficiency. Patients who had tests conducted for trabecular bone score, bone mineral density (BMD), homocysteine (Hcy) and 25-OH vitamin D at an interval of one year and met the inclusion criteria were enrolled in this retrospective study. Sixty-four patients with RA were enrolled and were divided into the following two groups: the first group (34 patients) had received treatment with bDMARDs and the second group (30 patients) had received csDMARDs. BDMARDs and csDMARDs had a positive influence on TBS and BMD. The best results were observed in the Adalimumab group (p = 0.033). Hyperhomocysteinemia and 25-OH vitamin D deficiency led to lower TBS values. Both bDMARDs and csDMARDs positively affected TBS and BMD in RA patients. High homocysteine serum levels or 25-OH vitamin D deficiency had a negative impact on TBS and BMD after 12 months. Our study aims to show the potential benefits of anti-TNF α drugs on TBS. This impact appears to be strongly associated with serum 25-OH vitamin D and homocysteine levels. Anti-TNF drugs may increase bone mineral density and microstructure. As a result, they may minimize the incidence of fractures in RA patients.

Trabecular Bone Score Improves Fracture Risk Discrimination in Postmenopausal Rheumatoid Arthritis Patients Receiving Glucocorticoids

Background

Bone mineral density (BMD) might not be a sensitive tool for predicting osteoporotic fracture risk among patients with rheumatoid arthritis (RA), especially when receiving glucocorticoids. Trabecular bone score (TBS), which has emerged as a new assessment technique representing bone microarchitecture and strength, may be considered an alternative approach.

Materials and Methods

In this cross-sectional analytical study, postmenopausal RA patients receiving glucocorticoids were identified from the postmenopause BMD database. The database included clinical data of postmenopausal outpatients who had at least one BMD measurement between January 2014 and December 2017. TBS was calculated from lumbar spine BMD with the microarchitecture assessment software. The presence of osteoporotic fractures, either vertebral or non-vertebral, was identified at the time of BMD measurement.

Results

A total of 64 postmenopausal RA patients receiving glucocorticoids were included. The TBS values were inversely associated with osteoporotic fractures, with a TBS cut-off of less than 1.24, showing the best accuracy with a sensitivity of 79% and a specificity of 84% in discriminating fractures. This newly proposed TBS threshold combined with a BMD T-score of -2.5 or less demonstrated a greater area under receiver operating characteristic curve in identifying patients with osteoporotic fractures than the BMD threshold alone (p value = 0.003).

Conclusion

The reduction in TBS was associated with an osteoporotic fracture in postmenopausal RA patients receiving glucocorticoids. Combining TBS and BMD in these patients incrementally improves fracture risk discrimination and may serve as a supplementary tool in identifying patients at greatest risk of osteoporotic fracture.

[Trabecular bone score in rheumatology : Are there benefits in comparison to bone densitometry alone?]

Patients with inflammatory rheumatic diseases have an increased risk of fractures due to the inflammatory potential of the disease and also because of the treatment with glucocorticoids that is often necessary. According to the current guidelines of the Governing Body on Osteology (DVO), the fracture risk can be assessed using dual energy X‑ray absorptiometry and can also be supplemented by measuring the trabecular bone score (TBS). The assessment of the TBS offers additional advantages, for example in glucocorticoid-induced osteoporosis and in patients with osteoproliferative changes of the spine (spondylarthritis) and thus optimizes the fracture risk assessment in the rheumatological patient population.

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.

Comparison of predictive value of FRAX, trabecular bone score, and bone mineral density for vertebral fractures in systemic sclerosis: A cross-sectional study

Assessing fracture risk is important for managing patients with systemic sclerosis (SSc). Vertebral fracture (VF) is the most common fracture and is associated with future VF and non-VF. We aimed to evaluate the predictive value of FRAX, trabecular bone score (TBS), and bone mineral density (BMD) for VFs, compared to rheumatoid arthritis (RA) patients and postmenopausal women, and to identify risk factors for VFs in SSc. In this cross-sectional study, prevalent VFs, 10-year probability of major osteoporotic fracture by FRAX (FRAX-MOF), TBS, and BMD were assessed in women with SSc (n = 69) and RA (n = 58), and postmenopausal women (n = 38). Risk factors for osteoporosis, modified Rodnan total skin score (mRSS), organ involvement, and patterns of nailfold capillaroscopy (NFC) were also evaluated. The accuracy of BMD (T-score ≤ -2.5), TBS and FRAX-MOF, with and without TBS adjustment, to detect prevalent VF was assessed by determining the area under the receiver operating characteristic (ROC) curve. Patients with SSc (14.5%) and RA (17.2%) had significantly more VFs than postmenopausal women (0%) (P = .031). Non-significant differences were observed in TBS and BMD of all groups. The FRAX-MOF were higher in RA (9.2%) than SSc group (6.1%) and postmenopausal women (5.5%) (P < .001). Based on the ROC curve, TBS-adjusted FRAX-MOF (0.803) showed largest area under curve (AUC) to detect the prevalent VFs, followed by FRAX-MOF (0.796), TBS (0.765), and BMD (0.588) in the SSc group. In the RA group, FRAX-MOF had the largest AUC (0.896), followed by TBS-adjusted FRAX-MOF (0.863), TBS (0.736), and BMD (0.686). The cutoffs for FRAX-MOF and TBS-adjusted FRAX-MOF for detecting VFs were 8.95% and 9.7% for SSc, and 14.5% and 14% for RA. No association between VFs and SSc subtypes, organ involvement, mRSS or NFC patterns was found. FRAX-MOF, with or without TBS, had better predictive value for VFs than BMD and TBS in SSc. However, FRAX-MOF underestimated the probability of VFs in SSc compared with RA.

Trabecular bone score in rheumatic disease

Patients with rheumatic diseases (RD) are at high risk of osteoporosis (OP) and osteoporotic fractures. The Trabecular bone score (TBS) is a relatively novel method of assessing bone quality, which independently predicts fracture risk regardless of bone mineral density (BMD). A lower TBS in patients with RD compared to controls is shown in most studies concerning TBS and RD. The data obtained indicate that TBS predicts fractures better in RD, especially in patients receiving glucocorticoids, than BMD or the FRAX algorithm. TBS degradation has been associated with disease activity in ankylosing spondylitis, systemic sclerosis, and rheumatoid arthritis in a few studies. However, there is little data in the literature on the effect of rheumatic disease therapy and OP treatment in patients with RD on predictive ability of TBS for incident fracture.

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.

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.

The usefulness of trabecular bone score in patients with ankylosing spondylitis

BACKGROUNDS/AIMS

This study was performed to reveal the usefulness of the trabecular bone score (TBS) in assessing bone strength in patients with ankylosing spondylitis (AS) in comparison with dual-energy X-ray absorptiometry (DXA) methods.

METHODS

A total of 215 AS patients (75.8% male) were enrolled from a single university hospital in Korea. Demographic and clinical information were assessed. Patients completed X-rays of the cervical and lumbar spine (L-spine), and spinal ankyloses were quantified using the modified Stoke AS Spine Score (mSASSS). Hip, anteroposterior and lateral L-spine bone mineral density (BMD) and TBS were assessed by DXA methods. Clinical characteristics and bone strength measurement results were compared between male and female AS patients. The accuracy of each bone strength evaluation method in predicting Fracture Risk Assessment Tool (FRAX) scores indicating moderate or higher fracture risk was compared by receiver operating characteristic curves in patients aged ≥ 40 years. Correlations between each bone strength measurement method and mSASSS were examined.

RESULTS

Male patients showed higher mSASSS and less prevalent peripheral joint involvement compared to female patients (p < 0.05). TBS, hip BMD, and L-spine lateral BMD showed comparably high areas under the curve (AUCs) for predicting FRAX-major osteoporotic fractures (MOF) ≥ 10% (AUC ranged 0.72 to 0.76). TBS negatively correlated with mSASSS in both male and female patients (p < 0.01).

CONCLUSION

TBS could predict the risk of MOF and is not influenced by spinal osteoproliferation in AS patients, even in those with advanced spinal changes.

Clinical Utility of Trabecular Bone Score (TBS) in Fracture Risk Assessment of Patients with Rheumatic Diseases Treated with Glucocorticoids

Chronic glucocorticoid therapy is associated with osteoporosis and can cause fractures in up to 50% of patients. Increased risk of fractures in patients with glucocorticoid-induced osteoporosis does not result only from the decreased bone mineral density (BMD) but also bone microarchitecture deterioration. Trabecular bone score (TBS) is a method complementary to DXA, providing additional information about trabecular bone structure. The aim of this study was to assess the clinical utility of TBS in fracture risk assessment of patients treated with glucocorticoids. Patients with rheumatic diseases treated with glucocorticoids for at least 3 months were enrolled. All recruited patients underwent DXA with additional TBS assessment. We analyzed the frequency of osteoporosis and osteoporotic fractures and assessed factors that might be associated with the risk of osteoporotic fractures. A total of 64 patients were enrolled. TBS and TBS T-score values were significantly lower in patients with osteoporosis compared to patients without osteoporosis. Low energy fractures occurred in 19 patients. The disturbed bone microarchitecture was found in 30% of patients with fractures without osteoporosis diagnosis based on BMD. In the multivariate analysis, only TBS and age were significantly associated with the occurrence of osteoporotic fractures. TBS reflects the influence of glucocorticoid therapy on bone quality better than DXA measured BMD and provides an added value to DXA in identifying the group of patients particularly prone to fractures.

Application of the Trabecular Bone Score in Clinical Practice

The trabecular bone score (TBS) was introduced as an indirect index of trabecular microarchitecture, complementary to bone mineral density (BMD), and is derived using the same dual energy X-ray absorptiometry images. Recently, it has been approved for clinical use in Korea. Therefore, we conducted a comprehensive review to optimize the use of TBS in clinical practice. The TBS is an independent predictor of osteoporotic fractures in postmenopausal women and men aged >50 years. The TBS is potentially useful in monitoring the skeletal effects of anabolic agents but not of antiresorptive agents. In postmenopausal women with type 2 diabetes mellitus, the TBS assesses osteoporotic fracture risk not captured by BMD. However, high body mass index and soft tissue thickness can cause underestimation of the TBS; however, this limitation has been improved in recent versions of the TBS software. However, a high precision error and low reproducibility limit the use of TBS. This review may provide information on the application of the TBS in clinical practice based on reliable evidence.

What Role Does Trabecular Bone Score Play in Chronic Inflammatory Rheumatic Diseases?

Patients suffering from rheumatic inflammatory diseases, e.g., systemic sclerosis, rheumatoid arthritis, and ankylosing spondylitis, are at risk of low bone mass. Dual-energy X-ray Absorptiometry (DXA) is the traditional radiological measurement technique for bone mineral density (BMD). The recently developed trabecular bone score (TBS) enhances the skeletal information provided by standard BMD. It re-analyzes the spatial dynamics of pixel intensity changes in lumbar spine DXA images, defining a quantitative index, characterizing trabecular bone microarchitecture. It has been demonstrated that low TBS values are associated with an increased incidence of fractures in patients with rheumatic diseases. These methods used together for bone damage evaluation can be of value to identify individuals who will potentially fracture. The main scientific literature on the clinical aspects of osteoporosis, including the use of TBS in evaluating this pathology, are herein reported aimed at shedding light on the role trabecular bone score plays in chronic inflammatory rheumatic diseases.

Relationship between Skeletal Muscle Mass, Bone Mineral Density, and Trabecular Bone Score in Osteoporotic Vertebral Compression Fractures

STUDY DESIGN

A retrospective observational study was performed.

PURPOSE

We investigated the relationships between skeletal muscle mass, bone mineral density (BMD), and trabecular bone score (TBS) in patients with osteoporotic vertebral compression fractures (VCFs).

OVERVIEW OF LITERATURE

The TBS has attracted attention as a measurement of trabecular bone microarchitecture. It is derived from data obtained using dual-energy X-ray absorptiometry (DXA) and is a reported indicator of VCFs, and its addition to the Fracture Risk Assessment Tool increases the accuracy of fracture prediction.

METHODS

BMD, skeletal muscle mass, and TBS were measured in 142 patients who visited Shimoshizu National Hospital from April to August 2019. Patients were divided into a VCF group and a non-VCF group. Whole-body DXA scans were performed to analyze body composition, including appendicular skeletal muscle mass index (SMI; lean mass [kg]/height [m2]) and BMD. The diagnostic criteria for sarcopenia was an appendicular SMI <5.46 kg/m2. A logistic regression analysis was conducted to identify the risk factors for VCFs.

RESULTS

The significant (p<0.05) findings (VCF group vs. non-VCF group, respectively) included age (79 vs. 70 years), femoral BMD (0.50 vs. 0.58 g/cm2), TBS (1.25 vs. 1.29), and lower limb muscle mass (8.6 vs. 9.9 kg). The VCF group was significantly older and had a lower femur BMD and decreased leg muscle mass than the non-VCF group. Based on the multiple logistic regression analysis, lower femoral BMD and decreased leg muscle mass were identified as risk factors for vertebral fracture independent of age, but the TBS was not.

CONCLUSIONS

Patients with VCFs had low BMD, a low TBS, and low skeletal muscle mass. Lower femoral BMD and decreased leg muscle mass were identified as risk factors for VCFs independent of age, whereas the TBS was not identified as a risk factor for VCFs.

Degraded microarchitecture by low trabecular bone score is associated with prevalent vertebral fractures in patients with systemic lupus erythematosus

PURPOSE

Recently, trabecular bone score (TBS) has emerged as an important supplementary assessment tool in osteoporosis diagnosis and management. The high incidence of fragility fracture within the non-osteoporotic range of bone mineral density (BMD), among systemic lupus erythematosus (SLE) patients, highlights the crucial role of bone microarchitecture in osteoporosis. This study aimed to evaluate whether TBS identified existing vertebral fractures (VF) more accurately than BMD in SLE patients.

METHODS

This study enrolled 147 SLE patients from the Asia Pacific Lupus Collaboration (APLC) cohort, who had BMD and TBS assessed from January 2018 until December 2018. Twenty-eight patients sustaining VF and risk factors associated with increased fracture occurrence were evaluated. Independent risk factors and diagnostic accuracy of VF were analyzed by logistic regression and ROC curve, respectively.

RESULT

The prevalence of vertebral fracture among SLE patients was 19%. BMD, T-score, TBS, and TBS T-score were significantly lower in the vertebral fracture group. TBS exhibited higher positive predictive value and negative predictive value than L spine and left femur BMD for vertebral fractures. Moreover, TBS had a higher diagnostic accuracy than densitometric measurements (area under curve, 0.811 vs. 0.737 and 0.605).

CONCLUSION

Degraded microarchitecture by TBS was associated with prevalent vertebral fractures in SLE patients. Our result suggests that TBS can be a complementary tool for assessing vertebral fracture prevalence in this population.

[Evaluation of the trabecular bone score (TBS) in routine clinical care of patients with inflammatory rheumatic and non-inflammatory diseases : Correlation with conventional bone mineral density measurement and prevalence of vertebral fractures]

Hintergrund

Osteoporosebedingte Frakturen sind bei Patienten mit rheumatoider Arthritis (RA) häufig. Die Messung der Knochenmineraldichte (KDM) mit der Dual-Energie-Röntgenabsorptionsmessung (DXA) allein sagt das Frakturrisiko nur begrenzt voraus. Der Trabecular Bone Score (TBS) ist ein Surrogatmarker für die trabekuläre Mikroarchitektur des Knochens, der das Frakturrisiko unabhängig von der KDM vorhersagen kann.

Ziel

Ermittlung der Prävalenz von KDM, TBS und osteoporotisch bedingten Wirbelkörperbrüchen („vertebral fractures“ [VF]) bei Patienten mit RA im Vergleich zu Kontrollen mit nichtentzündlichen Muskel-Skelett-Erkrankungen (MSK).

Methoden

Die Daten von Patienten mit von Rheumatologen diagnostizierter RA und verfügbaren TBS- und DXA-Messungen, die in unserem Krankenhaus von 2006 bis 2014 erhoben wurden, wurden retrospektiv analysiert. Den RA-Patienten wurden Kontrollen mit nichtentzündlichen MSK zugeordnet. Eine „reduzierte Knochengesundheit“ wurde definiert als ein T‑Score <−1,0 und/oder ein TBS-Wert <−1,31. Statistische Vergleiche wurden mit dem Mann-Whitney- und dem Wilcoxon-Test durchgeführt.

Ergebnisse

Es wurden 143 Patienten mit RA (Alter 72,1 ± 11,1 Jahre, 72 % weiblich) und 106 Kontrollen (Alter 69,6 ± 12,6 Jahre, 75 % weiblich) eingeschlossen. RA-Patienten hatten häufiger eine erniedrigte KDM (n = 102; 71,3 %) und einen erniedrigen TBS-Wert (n = 125; 87,4 %) als die Kontrollen (n = 63; 59,4 % und n = 79; 74,5 %, p = 0,049 und p = 0,009). RA-Patienten hatten mehr VF (n = 52, 36,4 %) als Kontrollen (n = 24, 22,6 %, p = 0,02). Insgesamt hatten 20 Patienten mit VF (26,3 %) eine normale Wirbelsäulen-KDM und 9 (11,8 %) auch eine normale Hüft-KDM. Bei Patienten mit VF war die Kombination eines niedrigen TBS bei normaler WS-KDM häufiger als ein normaler TBS bei niedriger WS-KDM (p = 0,008 für RA, p = 0,025 für Kontrollen).

Diskussion

VF treten bei Patienten mit normaler KDM auf. Bei Patienten mit VF wurde eine niedrige TBS bei normaler Wirbelsäulen-KDM häufiger gefunden als eine normale TBS bei niedriger Wirbelsäulen-KDM. Die Messung des TBS scheint für die Erkennung eines erhöhten Frakturrisikos bei RA-Patienten mit normaler WS-KDM nützlich zu sein.

The Trabecular Bone Score (TBS) Complements DXA and the FRAX as a Fracture Risk Assessment Tool in Routine Clinical Practice

PURPOSE OF THE REVIEW

There is an increasing body of evidence that the trabecular bone score (TBS), a surrogate of bone microarchitecture extracted from spine DXA, could play an important role in the management of patients with osteoporosis or at risk of fracture. The current paper reviews this published body of scientific literature on TBS and answers the most relevant clinical questions.

RECENT FINDINGS

TBS has repeatedly been proven to be predictive of fragility fractures, current and future, and this is largely independent of BMD, CRF, and the FRAX, and when used in conjunction with any one of these measures, it consistently enhances their accuracy. There also is a growing body of evidence indicating that the TBS has particular advantages over BMD for specific causes of increased fracture risk, like chronic corticosteroid excess, type-2 diabetes, and chronic kidney disease, and patients being treated with anti-aromatase and primary hyperparathyroidism, conditions wherein BMD readings are often misleading. TBS enhances performance of the FRAX tool, where its greatest utility appears to lie in its ability to accurately classify those patients whose BMD level lies close to the intervention threshold, aiding in decisions on whether treatment is warranted or not. Furthermore, TBS has also particular advantages over BMD in secondary osteoporosis. While the role of TBS with monitoring could be important as the different molecules impact logically TBS to various degrees, large clinical trials are still needed.

Trabecular bone score as a supplementary tool for the discrimination of osteoporotic fractures in postmenopausal women with rheumatoid arthritis

Rheumatoid arthritis (RA) is a risk factor for bone fragility, and its effect on fracture risk is independent of bone mineral density (BMD). The trabecular bone score (TBS) is a new indirect parameter of bone quality. In this study, BMD and the TBS were compared between female postmenopausal RA patients with and those without vertebral fractures (VFs).This study had a cross-sectional design. Two hundred seventy-nine postmenopausal women with RA aged 50 years or older were included in this study. TBS measurements were performed on the same vertebrae as those for the BMD measurements.Among the 279 subjects, 34 had VFs (12.5%). There was a significant difference in the TBS (P = .005) but not L-spine BMD (P = .142) between the subjects with and those without VFs. The odds ratio (OR) for the TBS per standard deviation decrease was significant, even after adjusting for confounding factors such as age, height, rheumatoid factor positivity, the disease activity score for 28 joints (DAS28), the cumulative dose of glucocorticoids (GCs), the time since menopause and osteoporosis drug use (OR = 2.86; 95% CI, 1.34-6.09), and L-spine BMD (OR = 2.57; 95% CI, 1.19-5.54). The TBS was negatively correlated with the cumulative dose of GCs, but not with the DAS28 or erythrocyte sedimentation rate. However, the correlation was an L-shaped nonlinear relationship.The TBS could be a supplementary tool for discriminating osteoporotic fractures in postmenopausal women with RA, and it may have a nonlinear relationship with the cumulative dose of GCs, but not with RA disease activity.

Trabecular Bone Score: A New DXA-Derived Measurement for Fracture Risk Assessment

Trabecular bone score (TBS) is a novel method that assesses skeletal texture from spine dual-energy X-ray absorptiometry (DXA) images. TBS improves fracture-risk prediction beyond that provided by DXA bone mineral density (BMD) and clinical risk factors, and can be incorporated to the Word Health Organization Fracture Risk Assessment tool (FRAX®) to enhance fracture prediction. There is insufficient evidence that TBS can be used to monitor treatment with bisphosphonates. TBS may be particularly helpful to assess fracture risk in diabetes. This article reviews technical and clinical aspects of TBS and its potential utility as a clinical tool to predict fracture risk.

Trabecular Bone Score and Incident Fragility Fracture Risk in Adults with Reduced Kidney Function

BACKGROUND AND OBJECTIVES

Trabecular bone score is a gray-level textural measure obtained from dual energy x-ray absorptiometry lumbar spine images that provides information independent of areal bone mineral density. The association between trabecular bone score and incident fractures in adults with reduced kidney function and whether this association differs from that of adults with normal kidney function are unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included 1426 participants ages ≥40 years old (mean age of 67 years) in the community-based Canadian Multicentre Osteoporosis Study. We stratified participants at cohort entry (2005-2008) by eGFR (eGFR<60 ml/min per 1.73 m2 [n=199; 72.4% stage 3a, 25.1% stage 3b, and 2.5% stage 4] versus ≥60 ml/min per 1.73 m2 [n=1227]). Trabecular bone score was obtained from lumbar spine (L1-L4) dual energy x-ray absorptiometry images, with a lower trabecular bone score representing worse bone structure. Over an average of 4.7 years follow-up (maximum follow-up of 5 years), we documented incident fragility (low-trauma) fracture events (excluding craniofacial, foot, and hand sites). We used a modified Kaplan-Meier estimator to determine the 5-year probability of fracture. Cox proportional hazard regression per SD lower trabecular bone score expressed the gradient of fracture risk.

RESULTS

Individuals with an eGFR<60 ml/min per 1.73 m2 who had a trabecular bone score value below the median (<1.277) had a significantly higher 5-year fracture probability than those above the median (18.1% versus 6.2%; P=0.01). The association between trabecular bone score and fracture was independent of bone mineral density and other clinical risk factors in adults with reduced and normal kidney function (adjusted hazard ratio per SD lower trabecular bone score: eGFR<60 ml/min per 1.73 m2: adjusted hazard ratio, 1.62; 95% confidence interval, 1.04 to 2.51; eGFR≥60 ml/min per 1.73 m2: adjusted hazard ratio, 1.44; 95% confidence interval, 1.13 to 1.83).

CONCLUSIONS

Lower lumbar spine trabecular bone score is independently associated with a higher fracture risk in adults with reduced kidney function. Additional study is needed to examine the association between trabecular bone score and fractures in individuals with diagnosed CKD-mineral and bone disorder.