Bone density testing in clinical practice

Abstract

The diagnosis of osteoporosis and monitoring of treatment is a challenge for physicians due to the large number of available tests and complexities of interpretation. Bone mineral density (BMD) testing is a non-invasive measurement to assess skeletal health. The "gold-standard" technology for diagnosis and monitoring is dual-energy X-ray absorptiometry (DXA) of the spine, hip, or forearm. Fracture risk can be predicted using DXA and other technologies at many skeletal sites. Despite guidelines for selecting patients for BMD testing and identifying those most likely to benefit from treatment, many patients are not being tested or receiving therapy. Even patients with very high risk of fracture, such as those on longterm glucocorticoid therapy or with prevalent fragility fractures, are often not managed appropriately. The optimal testing strategy varies according to local availability and affordability of BMD testing. The role of BMD testing to monitor therapy is still being defined, and interpretation of serial studies requires special attention to instrument calibration, acquisition technique, analysis, and precision assessment. BMD is usually reported as a T-score, the standard deviation variance of the patient's BMD compared to a normal young-adult reference population. BMD in postmenopausal women is classified as normal, osteopenia, or osteoporosis according to criteria established by the World Health Organization. Standardized methodologies are being developed to establish cost-effective intervention thresholds for pharmacological therapy based on T-score combined with clinical risk factors for fracture. RESUMO Densitometria Óssea na Prática Clínica.O diagnóstico e monitoração do tratamento da osteoporose é um desafio para os médicos devido ao grande número de testes disponíveis e a complexidades da interpretação. O exame da densidade mineral óssea é uma medida não-invasiva da avaliação da saúde esquelética. A tecnologia "padrão-ouro" para o diagnóstico e monitoração é a absorciometria por raios-X duo-energética (DXA) da coluna, quadril ou antebraço. O risco de fratura pode ser previsto usando DXA e outras tecnologias em vários sítios esqueléticos. Apesar das diretrizes para a medida de da DMO e identificação daqueles que mais provavelmente irão se beneficiar do tratamento, muitos pacientes não estão sendo testados ou recebendo tratamento. Mesmo pacientes com elevado risco de fratura, tais como aqueles em terapia de longo prazo com glicocorticóides, ou mesmo aqueles com fraturas por fragilidade prevalentes, quase nunca estão sendo conduzidos adequadamente. A estratégia diagnóstica ótima varia de acordo com a disponibilidade e acesso à medida da DMO. O papel da medida da DMO para monitorar terapia ainda está sendo definido, e a interpretação de estudos seriados requer

Does Osteoporosis with Type 2 Diabetes Mellitus (Diabetoporosis) increase the risk of fracture?

“…As it is a silent illness, it is generally diagnosed after the occurence of a bone fracture. Osteoporosis-related fractures have a severe impact on patient's quality of life and cause high healthcare costs [6,7]. DXA has been regarded as the gold standard analysis to diagnose osteoporosis [8].…”

Interpreting a DXA Scan in Clinical Practice

“…Fan beam provides the advantage of decreased scan times compared to single-beam systems, but these machines typically cost more because of the need for multiple X-ray detectors. Fan-beam systems use either a single-view or multiview mode to image the skeleton (Lewiecki and Borges 2006).…”

Can hip fracture prediction in women be estimated beyond bone mineral density measurement alone?

“…As mentioned, however, there is a large overlap of BMD between hip fracture patients and controls and only 4050% of patients with a hip fracture do have osteoporosis, indicating that BMD only partially reflects hip fracture risk. Bone strength is determined by many components including BMD, bone architecture (geometry), microarchitecture (trabecular number, thickness, perforation, and connectivity), cortical porosity, matrix properties, tissue mineralization density, crystal characteristics and damage accumulation and repair [Bouxsein, 2008;Lewiecki and Borges, 2006 (Bates et al 2002).…”

“…The mechanisms of action of inhibiting high bone turnover include a decrease in bone turnover and an increase in BMD, with preservation of bone microarchitecture, increased mineralization and geometrical changes in the hip that contribute to bone strength [Lewiecki and Borges, 2006]. Strontium ranelate increases BMD (up to 30% after 8 years) [Reginster et al 2009] and parameters of bone microarchitecture in the forearm [Ammann et al 2007], with only limited effects on markers of bone turnover [Meunier et al 2004].…”