Usefulness of the Trabecular Bone Score for assessing the 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.

Diffuse idiopathic skeletal hyperostosis (DISH) and trabecular bone score (TBS) in postmenopausal women: The Camargo cohort

OBJECTIVES

The potential relationship between diffuse idiopathic skeletal hyperostosis (DISH) and bone microstructure has not been studied in women. We aimed to assess the association between the trabecular bone score (TBS) and DISH in postmenopausal women, as well as the role of other parameters related to bone metabolism, such as bone mineral density (BMD), calciotropic hormones, and bone remodeling markers.

METHODS

Cross-sectional study, nested in a prospective population-based cohort (Camargo cohort). Clinical covariates, DISH, TBS, vitamin D, parathormone, BMD and serum bone turnover markers, were analyzed.

RESULTS

We have included 1545 postmenopausal women (mean age, 62±9 years). Those with DISH (n = 152; 8.2%) were older and had a significantly higher prevalence of obesity, metabolic syndrome, hypertension, and type 2 diabetes mellitus (p<0.05). Moreover, they had lower TBS values (p = 0.0001) despite having a higher lumbar spine BMD (p<0.0001) and a higher prevalence of vertebral fractures than women without DISH (28.6% vs. 15.1%; p = 0.002). When analyzing DISH through Schlapbach grades, women without DISH had a median TBS value consistent with a normal trabecular structure while the values for women with DISH from grades 1 to 3 were consistent with a partially degraded trabecular structure. Women with vertebral fractures and DISH had a mean TBS corresponding to a degraded trabecular structure (1.219±0.1). After adjusting for confounders, the estimated TBS means were 1.272 (1.253-1.290) in the DISH group, and 1.334 (1.328-1.339) in the NDISH group (p<0.0001).

CONCLUSION

An association between DISH and TBS has been shown in postmenopausal women, in which hyperostosis has been significantly and consistently related to trabecular degradation and, therefore, to deterioration in bone quality after adjusting for confounding variables.

Trabecular Bone Score as a Reliable Measure of Lumbar Spine Bone Microarchitecture in Acromegalic Patients

Although GH and IGF-1 excess has a controversial impact on bone mineral density (BMD), acromegalic patients display variable degrees of bone structure impairment. In this study, we aim to investigate the usefulness of trabecular bone score (TBS), compared to BMD, in identifying acromegalic patients with impaired lumbar spine trabecular microarchitecture. Forty-four acromegalic patients were investigated for disease control, metabolic and gonadal status, bone metabolism parameters, and the presence of vertebral fractures (VFs). Patients and matched healthy controls underwent BMD and TBS examination. Mean TBS values were lower in patients than in controls (p < 0.001), without significant differences in mean lumbar and femoral BMD. TBS values were significantly higher in controlled patients compared to the uncontrolled ones (p = 0.012). No significant differences were found in bone markers with respect to disease control. Mean TBS or lumbar BMD did not significantly differ in patients with or without VFs (prevalence 11.4%). TBS and BMD levels were lower in hypogonadal patients compared to the eugonadal ones (p = 0.030 and p < 0.001, respectively). In conclusion, TBS values are significantly lower in patients than in controls, confirming the presence of impaired lumbar spine trabecular bone in acromegaly. Both uncontrolled disease and hypogonadism contribute to TBS deterioration in acromegaly.

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.

Glucocorticoids and Trabecular Bone Score

TBS (Trabecular Bone Score) is the latest tool for clinicians to evaluate bone micro-architecture based on a pixel greyscale, which is provided by lumbar dual-energy X-ray absorptiometry (DXA). Its use enhances fracture prediction in addition to DXA-BMD (Bone Mineral Density). This is independent of fracture risk assessment (FRAX) and DXA results. We present a narrative review regarding the connection between TBS and Glucocorticoids (GC), either as a drug used for different conditions or as a tumor-produced endogenous excess.

TBS is a better discriminator for GC-induced vertebral fractures compared to DXA-BMD. This aspect is similarly available for patients with osteoporosis diagnosed by DXA. TBS is inversely correlated with the cumulative dose of GC (systemic or inhaled), with disease duration, and positively correlated with respiratory function in patients with asthma. Low TBS values are found in females with a T-score at the hip within the osteoporosis range, with diabetes mellitus, or who use GC. Lumbar TBS is a screening tool in menopausal women with type 2 diabetes mellitus. TBS is an independent parameter that provides information regarding skeleton deterioration in diabetic patients receiving GC therapy in a manner complementary to DXA-BMD. TBS might become an essential step regarding the adrenalectomy decision in patients with adrenal incidentaloma in whom autonomous cortisol secretion might damage bone micro-architecture. TBS currently represents a standard tool of fracture risk evaluation in patients receiving GC therapy or with endogenous Cushing’s syndrome, a tool easy to be applied by different practitioners since GCs are largely used

Trabecular bone score improves fracture risk assessment in glucocorticoid-induced osteoporosis

OBJECTIVE

To analyse the clinical utility of trabecular bone score (TBS) evaluation for fracture risk assessment in glucocorticoid (GC)-treated patients compared with BMD assessment.

METHODS

One hundred and twenty-seven patients on GC treatment were included [mean age 62 (18) years, 63% women] in this cross-sectional study. The medical history, anthropometric data, lumbar and femoral BMD (DXA) [considering osteoporosis (OP): T-score ⩽-2.5], TBS (considering degraded microarchitecture: <1.230) and dorsolumbar X-ray [to assess vertebral fractures (VF)] were evaluated. BMD and TBS sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were evaluated to determine the diagnostic accuracy of the two methods.

RESULTS

All patients were receiving GC treatment for autoimmune diseases during 47.7 (68.9) months at a mean daily dose of 14.5 mg; 17% had VF, 28% any type of fragility fracture (VF + non-VF), 29% OP and 52% degraded microarchitecture. Degraded microarchitecture was significantly more frequent than densitometric OP in patients with VF (76% vs 38%) and with any fragility fracture (69% vs 36%). For VF, TBS and BMD sensitivity, specificity, PPV, and NPV were 0.76, 0.53, 0.25 and 0.92, and 0.38, 0.72, 0.22 and 0.85, respectively. Specificity increased to 0.89 for VF and 0.9 for any fragility fracture on combining BMD+TBS. TBS had better ability than BMD to discriminate between patients with fracture, especially VF (area under the curve = 0.73).

CONCLUSION

TBS seems to have greater discriminative power than BMD for fracture risk assessment in GC-treated patients, confirming the utility of this method as a complementary tool in the diagnosis of GC-induced OP.

Vertebral fracture risk in glucocorticoid-induced osteoporosis: the role of hypogonadism and corticosteroid boluses

OBJECTIVE

The aim of this study was to identify the risk factors associated with fragility fracture (FF) development in glucocorticoid (GC)-treated patients.

METHODS

127 patients (aged 62±18 years, 63% women) on GC-treatment (mean dose 14.5±14.1 mg/day and duration 47.7±69 months) were included. The clinical data collected included bone metabolism study (including gonadal axis), GC-treatment, disease activity, dual-energy X-ray absorptiometry analysis (evaluating densitometric osteoporosis (OP) and trabecular bone score (TBS) degraded microarchitecture values (DMA)), X-ray (assessing vertebral fractures (VF)), FRAX risk (GC-adjusted) and previous FF.

RESULTS

17% of the patients had VF, 28% FF (VF and/or non-VF), 29% OP and 52% DMA. Patients with VF received more GC boluses (57.1% vs 29.5%, p=0.03), were older (68±13 vs 60±19 years, p=0.02), postmenopausal (100% vs 67%, p=0.02), had low testosterone levels (57% vs 11%, p=0.02), lower TBS values (1.119±0.03 vs 1.237±0.013, p<0.001) and higher FRAX risk (17.2±16 vs 9.3±7.6, p=0.003). Patients with FF showed higher accumulated GC doses (16.6±18.4 vs 11.1±12.9 g, p=0.046). On multivariate analysis, hypogonadism (OR 12.38; 95% CI 1.85 to >100, p=0.01) and having received GC boluses (OR 3.45; 95% CI 1.04 to 12.15, p=0.01) were the main factors related to VF. Hypogonadism (OR 7.03; 95% CI 1.47 to 38.37, p=0.01) and FRAX >20 (OR 7.08; 95% CI 1.28 to 53.71, p=0.02) were factors related to FF.

CONCLUSION

Hypogonadism is the principal risk factor for developing fractures in GC-treated men and women, whereas receiving GC boluses is a major factor for VF. These results indicate the importance of evaluating the gonadal axis in these patients.

[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.