Dept of Medicine, Austin Health, The University of Melbourne, Melbourne, Australia; Depts of Medicine and Endocrinology, Austin Health, The University of Melbourne, Melbourne, Australia.
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia.
Bone. 2022 Jan;154:116260. doi: 10.1016/j.bone.2021.116260. Epub 2021 Nov 18.
Measurement of bone mineral density (BMD) is recommended in patients with chronic kidney disease (CKD). However, most persons in the community and most patients with CKD have osteopenia, suggesting fracture risk is low. Bone loss compromises bone microarchitecture which increases fragility disproportionate to modest deficits in BMD. We therefore hypothesized that patients with CKD have reduced estimated failure load due to deterioration in microarchitecture irrespective of whether they have normal femoral neck (FN) BMD, osteopenia or osteoporosis.
We measured distal tibial and distal radial microarchitecture in 128 patients with CKD and 275 age- and sex-matched controls using high resolution peripheral quantitative computed tomography, FN-BMD using bone densitometry and estimated failure load at the distal appendicular sites using finite element analysis.
Patients versus controls respectively had: lower tibial cortical area 219 (40.7) vs. 237 (35.3) mm, p = 0.002, lower cortical volumetric BMD 543 (80.7) vs. 642 (81.7) mgHA/cm due to higher porosity 69.6 (6.19) vs. 61.9 (6.48)% and lower matrix mineral density 64.2 (0.62) vs. 65.1 (1.28)%, lower trabecular vBMD 92.2 (41.1) vs. 149 (43.0) mgHA/cm due to fewer and spatially disrupted trabeculae, lower FN-BMD 0.78 (0.12) vs. 0.94 (0.14) g/cm and reduced estimated failure load 3825 (1152) vs. 5778 (1467) N, all p < 0.001. Deterioration in microarchitecture and estimated failure load was most severe in patients and controls with osteoporosis. Patients with CKD with osteopenia and normal FN-BMD had more deteriorated tibial microarchitecture and estimated failure load than controls with BMD in the same category. In univariate analyses, microarchitecture and FN-BMD were both associated with estimated failure load. In multivariable analyses, only microarchitecture was independently associated with estimated failure load and accounted for 87% of the variance.
Bone fragility is likely to be present in patients with CKD despite them having osteopenia or normal BMD. Measuring microarchitecture may assist in targeting therapy to those at risk of fracture.
患有慢性肾脏病（CKD）的患者建议测量骨密度（BMD）。然而，社区中的大多数人和大多数 CKD 患者都有骨量减少，这表明骨折风险较低。骨丢失会损害骨微结构，使其变得脆弱，而不仅仅是 BMD 适度减少。因此，我们假设无论 CKD 患者的股骨颈（FN）BMD 是否正常、骨量减少或骨质疏松，其微结构恶化都会导致估计的失败负荷降低。
我们使用高分辨率外周定量计算机断层扫描（HR-pQCT）测量了 128 名 CKD 患者和 275 名年龄和性别匹配的对照者的远端胫骨和远端桡骨微结构，使用骨密度仪测量 FN-BMD，并使用有限元分析（FEA）测量远端附肢部位的估计失效负荷。
与对照组相比，患者组分别具有：较低的胫骨皮质面积 219（40.7）比 237（35.3）mm，p=0.002，较低的皮质体积 BMD 543（80.7）比 642（81.7）mgHA/cm，由于较高的孔隙率 69.6（6.19）比 61.9（6.48）%和较低的基质矿密度 64.2（0.62）比 65.1（1.28）%，较低的小梁 vBMD 92.2（41.1）比 149（43.0）mgHA/cm，由于小梁数量较少且空间分布紊乱，较低的 FN-BMD 0.78（0.12）比 0.94（0.14）g/cm，以及较低的估计失效负荷 3825（1152）比 5778（1467）N，所有差异均具有统计学意义（p<0.001）。在骨质疏松症患者和对照组中，微结构和估计失效负荷的恶化最为严重。患有 CKD 的骨量减少和 FN-BMD 正常的患者，其胫骨微结构和估计失效负荷比同类别 BMD 正常的对照组患者恶化更为严重。在单变量分析中，微结构和 FN-BMD 均与估计的失效负荷相关。在多变量分析中，只有微结构与估计失效负荷独立相关，占总方差的 87%。
尽管 CKD 患者存在骨量减少或正常 BMD，但他们的骨骼脆性可能仍然存在。测量微结构可能有助于针对骨折风险的患者进行靶向治疗。
