Resch A, Schneider B, Bernecker P, Battmann A, Wergedal J, Willvonseder R, Resch H
Department of Radiology, University, Vienna, Austria.
AJR Am J Roentgenol. 1995 Jun;164(6):1447-50. doi: 10.2214/ajr.164.6.7754890.
Vertebral fracture is the most frequent manifestation of osteoporosis in women. Because there is a lack of information about bone density and the occurrence of fractures in men with osteoporosis, we evaluated the relationship between vertebral fractures and spinal bone mineral density (BMD) to determine if there is a threshold of BMD below which fractures are likely to occur.
Radiographs of the spine and BMD measurements of the lumbar spine as measured by quantitative CT were obtained in 201 men 21-86 years old (mean age, 68 +/- 4 years) who were referred consecutively for osteoporosis screening. Radiographs were interpreted for the presence or absence of vertebral fractures. The probability of fractures was determined after classifying the patients into subgroups according to their quantitative CT values. The relationship of spinal bone mass to spinal fracture was examined by both logistic regression and receiver operating characteristic (ROC) analysis.
Seventy-one patients were classified as having definite vertebral compression fractures. Spinal BMD was 132 +/- 34 mg/ml for the 130 men without vertebral fractures and 75 +/- 22 mg/ml for the 71 men with vertebral fractures (p < .001). The number of fractures per patient and the BMD were negatively correlated (r = -0.71, p < 0.0001). When a BMD of 100 mg/ml was given as a fracture threshold, 15% of the patients without fractures were below this value and 14% of the patients with fractures were above this threshold. Quantifying the overlap between values from patients with and without fractures by ROC analysis, the value of 100 mg/ml gave a sensitivity of 86%. Logistic regression showed 105 mg/ml as the most discriminate value, resulting in a sensitivity of 90%. Logistic regression analysis of the predicted fracture probability also indicated that age does not significantly influence the regression curve.
We found that direct quantitative CT measurement of the BMD of the vertebral body is a highly efficient approach to distinguish men without vertebral fractures from those with fractures. Thus, a fracture-threshold concept could provide a quantitative criterion to identify men at high risk for vertebral fractures.
椎体骨折是女性骨质疏松最常见的表现形式。由于缺乏有关男性骨质疏松患者骨密度及骨折发生情况的信息，我们评估了椎体骨折与脊柱骨密度（BMD）之间的关系，以确定是否存在一个骨密度阈值，低于该阈值骨折就可能发生。
对201名年龄在21 - 86岁（平均年龄68±4岁）因骨质疏松筛查而连续就诊的男性，拍摄脊柱X线片并通过定量CT测量腰椎骨密度。对X线片进行解读以确定是否存在椎体骨折。根据定量CT值将患者分为亚组后确定骨折概率。通过逻辑回归和受试者工作特征（ROC）分析来研究脊柱骨量与脊柱骨折的关系。
71名患者被归类为有明确的椎体压缩性骨折。130名无椎体骨折男性的脊柱骨密度为132±34mg/ml，71名有椎体骨折男性的脊柱骨密度为75±22mg/ml（p<0.001）。每位患者的骨折数量与骨密度呈负相关（r = -0.71，p<0.0001）。当将100mg/ml的骨密度作为骨折阈值时，15%无骨折的患者低于该值，14%有骨折的患者高于该阈值。通过ROC分析量化有骨折和无骨折患者数值之间的重叠情况，100mg/ml的值敏感性为86%。逻辑回归显示105mg/ml为最具鉴别力的值，敏感性为90%。对预测骨折概率的逻辑回归分析还表明年龄对回归曲线无显著影响。
我们发现通过直接定量CT测量椎体骨密度是区分无椎体骨折男性与有骨折男性的高效方法。因此，骨折阈值概念可为识别椎体骨折高危男性提供定量标准。
