The fracture risk index and bone mineral density as predictors of vertebral structural failure
The fracture risk index and bone mineral density as predictors of vertebral structural failure
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DOI：
10.1007/s00198-005-1893-5
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发表时间：
2006-01-01
影响因子：
4
通讯作者：
Seeman, E
中科院分区：
文献类型：
--
作者：
Duan, YB;Duboeuf, F;Seeman, E
当骨上的负荷接近或超过骨的承受能力时，结构破坏的可能性就越来越大。椎体骨折风险指数（FRI）以压缩应力（单位面积载荷）与估计的破坏应力之比来表达结构破坏的风险，因此应该比单独替代骨强度的脊柱面积骨密度（aBMD）或体积骨密度（vBMD）更敏感和更具体地预测椎体骨折。为了解决这个问题，我们分析了澳大利亚墨尔本89名绝经后椎体骨折妇女和306名对照的病例对照研究结果，以及法国里昂一项为期10年的社区前瞻性研究的结果，其中30名绝经后椎体骨折妇女与150名对照进行了比较。采用双x线吸收仪测定第三腰椎的FRI、vBMD和脊柱aBMD。在横断面分析中，FRI每增加一个SD，椎体骨折风险增加2.1倍（95%可信区间[CI]， 1.55-2.73），而aBMD或vBMD每减少一个SD，椎体骨折风险增加4.0倍（95% CI，分别为2.69-6.18和2.65-6.94）。通过受试者工作特征（ROC）分析，FRI在区分病例和对照组方面的敏感性和特异性均低于aBMD （ROC下面积，0.76 vs 0.84, p < 0.01）。ROC曲线下面积在FRI和vBMD之间没有差异（0.76 vs 0.79， NS）。在前瞻性数据集中，FRI不能预测[风险比，HR, 1.20 (95% CI, 0.9-1.7)]，与aBMD [HR， 2.4 (95% CI, 1.5-3.8)]和vBMD [HR， 2.1 (95% CI, 1.39-3.17)]相反。两项研究中，FRI >= 1的临界值与aBMD T评分-2.5 SD相比，敏感性也较低。FRI和aBMD T -评分在检测骨折方面的一致性较差（kappa=0.13-0.18）；每种方法只能识别出50%左右的骨折病例。在样本量的限制下，我们得出结论，在区分骨折病例和对照组时，应用脊柱生物力学指标（如FRI）并不比传统的aBMD或vBMD更好。FRI可能不能预测椎体骨折。
Structural failure becomes increasingly likely as the load on bone approximates or exceeds the bone's ability to withstand it. The vertebral fracture risk index (FRI) expresses the risk for structural failure as a ratio of compressive stress (load per unit area) to estimated failure stress, and so should be a more sensitive and specific predictor of vertebral fracture than spine areal BMD (aBMD) or volumetric BMD (vBMD), surrogates of bone strength alone. To address this issue, we analyzed the results of a case-control study of 89 postmenopausal women with vertebral fractures and 306 controls in Melbourne, Australia, and a 10-year community-based prospective study in which 30 postmenopausal women who had incident vertebral fractures were compared with 150 controls in Lyon, France. The FRI and vBMD of the third lumbar vertebral body and spine aBMD were derived using dual X-ray absorptiometry. In the cross-sectional analysis, each SD increase in FRI was associated with 2.1-fold (95% confidence interval [CI], 1.55-2.73) increased vertebral fracture risk, while each SD decrease in aBMD or vBMD was associated with 4.0-fold (95% CI, 2.69-6.18 and 2.65-6.94, respectively) increase in risk. Using receiver operating characteristic (ROC) analysis, the FRI was less sensitive and specific than aBMD in discriminating cases and controls (area under ROC, 0.76 vs 0.84, p < 0.01). The area under ROC curve did not differ between FRI and vBMD (0.76 vs 0.79, NS). In the prospective data set, the FRI was not predictive [hazard ratio, HR, 1.20 (95% CI, 0.9-1.7)] and was in contrast to aBMD [HR, 2.4 (95% CI, 1.5-3.8)] and vBMD [HR, 2.1 (95% CI, 1.39-3.17)]. There was also lower sensitivity using a cutoff value of FRI >= 1 compared with aBMD T -score of -2.5 SD in both studies. There was poor agreement (kappa=0.13-0.18) between FRI and aBMD T -scores in detecting fractures; each method only identified around 50% of fractured cases. Within the constraints of the sample size, we concluded that applying a biomechanical index such as FRI at the spine is no better in discriminating fracture cases and controls than conventional aBMD or vBMD. The FRI may not predict incident vertebral fractures.