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Evidence-based practice in frailty
Published in Shibley Rahman, Living with frailty, 2018
Osteoporosis is a skeletal disease that reduces bone density and increases the risk of fracture (Szulc and Bouxsein, 2010). Osteoporosis is a systemic skeletal disease characterised by low bone mass and microarchitectural deterioration of bone tissue that leads to increased bone fragility and a consequent increase in fracture risk (NIH Consensus Development Panel on Osteoporosis Prevention, Diagnosis, and Therapy, 2001). Osteoporosis can occur without a known underlying cause, and is diagnosed in clinical practice by the presence of a fragility fracture or using bone mineral density (BMD) criteria. The BMD criteria were developed by the WHO on the basis of epidemiological data that describe the normal distribution of BMD in a reference population comprising healthy young adults (Writing Group for the ISCD Position Development Conference, 2004). Recently, 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 (Hans et al., 2017).
Assessment of fracture risk
Published in Nicholas C. Harvey, Cyrus Cooper, Osteoporosis: a lifecourse epidemiology approach to skeletal health, 2018
Eugene V McCloskey, William D Leslie, John A Kanis
Several of the clinical risk factors identified, for example alcohol consumption, glucocorticoid use and prior fractures, take no account of dose-response and provide instead a risk ratio for an average dose or exposure (21–23). In patients with a higher than average exposure, for example a daily dose of prednisolone of 10 to 15 mg, it should be recognised that the fracture probability is likely to be an underestimate; in the case of glucocorticoids, an estimate of this underestimation has been examined using data from the General Practice Research Database (GPRD) in the UK (24). At present the FRAX tool limits BMD inputs to that measured at the femoral neck, but other bone measurements can provide information on fracture risk; recent studies have examined the potential modification of the FRAX outputs by taking into account lumbar spine BMD or trabecular bone score, both of which contribute independently to fracture risk but appear to have limited overall impact on reclassifying individuals across assessment or intervention thresholds (25–28). Such approaches are probably best used in patients with fracture probabilities lying close to intervention thresholds.
Metabolic and endocrine bone disorders
Published in Ashley W. Blom, David Warwick, Michael R. Whitehouse, Apley and Solomon’s System of Orthopaedics and Trauma, 2017
Dual-energy X-ray absorptiometry (DXA) This is now the method of choice. Precision and accuracy are excellent, radiation exposure is not excessive and it is low-cost (Blake and Fogelman, 2009). Measurements are usually taken from the lumbar spine and hip, but they can also be taken from the distal forearm and total body (Figure 7.11). Additional investigations carried out by the DXA machine and software that can help improve fracture prediction include Vertebral Fracture Assessment (VFA) and Trabecular Bone Score (TBS). Bone mass values from DXA scans are two-dimensional estimates of bone density presented as the number of standard deviations below the young adult mean (T score) and the number of standard deviations below the age-matched mean (Z score). The World Health Organization (WHO) has defined osteoporosis as a T score below −2.5, osteopenia as a T score between −1.0 and −2.5, and normal bone mass as above −1.0 (WHO Technical Support Series). VFA can be useful as it provides a low-resolution image of the entire lateral spine that can be assessed for the presence of vertebral fractures. TBS provides an additional measurement of bone microarchitecture based on bone texture of the lumbar spine.
New insights into the diagnosis and management of bone health in premature ovarian insufficiency
Published in Climacteric, 2021
H. H. Nguyen, F. Milat, A. J. Vincent
The Trabecular bone score (TBS) is determined by DXA software that calculates a gray-level textural index derived from routine lumbar spine DXA images and is an indirect measure of trabecular architecture/quality [52,54]. A low TBS is associated with vertebral, hip and major osteoporotic fractures in postmenopausal women, independent of BMD, with similar findings in older men and other conditions associated with secondary osteoporosis. Given that estrogen deficiency is associated with fractures at sites rich in trabecular bone, and the TBS may not be correlated with height [54], it is an attractive bone imaging tool in women with POI, particularly in TS populations where short stature is prevalent. Limited literature suggests that a degraded TBS is influenced by a delay in HRT initiation following POI onset [28,55]. In a recent publication by our group, we found a strong association between low TBS and fracture prevalence in 58 women with TS [28]. Thus, the TBS may be a useful adjunct to DXA-derived BMD in assessing skeletal risk in POI cohorts; however, this software requires further validation.
Enhancing care for people living with HIV: current and future monitoring approaches
Published in Expert Review of Anti-infective Therapy, 2021
Franco Maggiolo, Alessandra Bandera, Stefano Bonora, Marco Borderi, Andrea Calcagno, Annamaria Cattelan, Antonella Cingolani, Nicola Gianotti, Miriam Lichtner, Sergio Lo Caputo, Giordano Madeddu, Paolo Maggi, Giulia Carla Marchetti, Renato Maserati, Silvia Nozza, Stefano Rusconi, Maurizio Zazzi, Antonio Di Biagio
Portable quantitative ultrasonometry (QUS) is an alternative technique to provide information about bone density, bone strength, and the BTM in PLWHIV. QUS is easy to use, hence could be used as an alternative to screen HIV patients for altered bone status [85]. Assessment for subclinical vertebral fractures can be done by lateral radiographs of the lumbar and thoracic spine or DEXA-based vertebral fracture assessment [86]. The trabecular bone score (TBS) is a novel index of bone microarchitecture which improves fracture prediction independent of BMD [87]. PLWHIV have lower TBS independently from lumbar spine BMD. Microindentation provides additional and necessary information to DEXA about bone health in treated HIV patients, and because of its convenience and feasibility, it could be routinely applied to assess bone health in clinical practice [88].
Bone health and hyperglycemia in pediatric populations
Published in Critical Reviews in Clinical Laboratory Sciences, 2020
Wojciech J. Bilinski, Przemyslaw T. Paradowski, Grazyna Sypniewska
Bone health may be assessed in different ways: BMD, bone strength, bone microarchitecture (measured by magnetic resonance imaging (MRI) or high-resolution peripheral quantitative computed tomography), and bone turnover. It has been suggested that changes in bone quality, particularly in type 2 diabetes (T2DM), may be better explained using other bone outcome indicators than BMD [35]. The trabecular bone score, measured by dual-energy X-ray absorptiometry (DXA), seems to be a good surrogate indicator of bone microarchitecture in patients with prediabetes and diabetes, whereas quantitative bone histomorphometry (the gold standard) and circulating biochemical markers of bone formation and bone resorption are indicators of bone turnover [35]. Histomorphometry with double tetracycline administration has some advantages over circulating bone turnover markers as it permits assessment of formation and mineralization of trabecular and cortical bone. However, it allows assessment of only a small biopsy sample taken from the iliac crest and it is a time-consuming procedure [36]. Another technique to study local bone turnover is fluoride isotope positron emission tomography scanning, which is expensive and not widely used [37]. Circulating bone turnover markers correlated only weakly with quantitative bone histomorphometry. Nonetheless measurement of bone markers in the circulation is a minimally invasive and relatively inexpensive procedure that reflects the metabolism of the entire skeleton [38].