The Effects Of Inherent Inaccuracies In DXA In Vivo BMD Measurements On Osteopenic/Osteoporotic Diagnostics/Prognositics

主要是绝经后妇女和男女老年人的骨质疏松症（多孔骨）及其相关骨折构成了一个重大、广泛和迅速增长的公共卫生问题。在澳大利亚和全世界，骨质疏松症已经是一个主要的健康成本负担，而且随着易患骨质疏松症的年龄或以上的人口比例急剧增加，在未来几十年里，骨质疏松症的负担将急剧增加。目前对骨质疏松症、骨骼的骨矿物质状态、骨骼的机械完整性和骨折风险的诊断评估主要基于使用双能x线骨密度仪（DXA）测量给定个体的骨矿物质密度（BMD）的x射线吸收测量。延缓、改善或逆转骨质疏松症低骨密度状况的新药现已出现，但除非证明患者骨密度足够低，否则不能开处方。这些药物的疗效通常被认为在骨质疏松症（骨质减少）的早期阶段是最大的，它们的有效性是根据dxa测量的骨矿物质密度来评估的。该项目的首席研究员已经通过发表的定量分析和模拟研究表明，这种骨密度测量本质上是不准确的；误差在20%及以上的情况很容易发生，特别是对那些处于骨质疏松症早期阶段的患者，以及那些处于或高于骨质疏松症易发年龄的患者——这些人的骨密度值往往是他们最关心的。这些系统性的DXA不准确可能大到足以掩盖骨质疏松症的存在或导致错误的诊断和患者监测结果。目前的项目，在任何地方都是第一次，旨在定量地建立这些不准确的程度，使用实际的DXA密度计利用复杂和精确的方法。

Osteoporosis (porous bone) and consequent associated bone fractures of mainly post-menopausal women and the elderly of both genders constitutes a significant, widespread and rapidly growing public health problem. It is already a major health-cost burden in Australia and worldwide and is set to increase dramatically over the next few decades as the proportion of the population at or above the osteoporosis-prone age increases sharply. Current diagnostic evaluations of osteoporosis, bone mineral status of the skeleton, mechanical integrity of bone, and bone fracture risk are mainly based on X-ray absorption measurements of a given individual's bone mineral density (BMD) using Dual-energy X-ray Absorptiometric (DXA) bone densitometer instrumentation. New drugs to retard, ameliorate, or reverse the low bone mineral density condition of osteoporosis are now becoming available, but cannot be prescribed unless sufficiently low BMD is demonstrated for a given patient. The efficacy of these drugs is usually held to be greatest at the earliest stage of osteoporosis (osteopenia) and their effectiveness evaluated on the basis of DXA-measured bone mineral density. The Chief Investigator of this project has already shown by published quantitative analysis and simulation studies that such BMD measurements are inherently inaccurate; that errors of 20% and greater can readily pertain, particularly for those patients at the early stages of osteoporosis and those at or above the osteoporosis-prone age -- the very individuals for whom bone mineral density values are often of paramount interest and concern. These systematic DXA inaccuracies can be large enough to either mask the presence of osteoporosis or lead to false diagnoses and patient monitoring results. The present project, for the first time anywhere, is desiged to quantitatively establish the extent of these inaccuracies using actual DXA densitometers utilizing sophisitcated and precise methods.