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

骨质疏松症(多孔骨)和随之而来的相关骨折，主要是绝经后妇女和老年人，无论男女，都是一个重大的、普遍的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医疗成本负担，随着处于或超过骨质疏松症易发年龄的人口比例急剧增加，它将在未来几十年内急剧增加。目前对骨质疏松症、骨骼的骨矿物质状态、骨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射线吸收测量仪(DXA)对给定个体的骨密度(BMD)的X射线吸收测量。延缓、改善或逆转骨质疏松症的低骨密度状态的新药现在已经出现，但除非对特定患者证明足够低的骨密度，否则不能开出处方药。通常认为这些药物在骨质疏松症(骨量减少)的早期阶段的疗效最好，并根据DXA测量的骨密度来评估它们的有效性。这个项目的首席调查员已经通过已发表的定量分析和模拟研究表明，这种骨密度测量本身就是不准确的；20%或更大的误差很容易适用于那些处于骨质疏松症早期阶段的患者和那些处于或超过骨质疏松症易发年龄的患者--这些人的骨密度值往往是人们最感兴趣和最关心的。这些系统性的DXA误差可能大到足以掩盖骨质疏松的存在，或者导致错误的诊断和患者监测结果。本项目首次在任何地方使用实际的DXA密度计，利用精确和精确的方法来定量地确定这些不准确的程度。

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.