Qi Q, Monier-Faugere M C, Geng Z, Malluche H H
Department of Internal Medicine, University of Kentucky, Lexington, USA 40536-0084.
Am J Kidney Dis. 1995 Oct;26(4):622-31. doi: 10.1016/0272-6386(95)90599-5.
With the increasing occurrence of adynamic bone disease, it is essential to determine the level of bone turnover in chronically dialyzed patients before instituting vitamin D therapy. To assess the value of serum parathyroid hormone (PTH) levels for prediction of bone turnover, we determined sensitivity, specificity, and predictive value positive of serum PTH, alone or in combination with other variables, in 79 patients who underwent one or two bone biopsies. Serum PTH levels were determined by a radioimmunometric assay and were obtained at the time of bone biopsies. Patients were classified into (1) low or normal and (2) high bone turnover according to the value of activation frequency of bone. There were 57 biopsy specimens taken from hemodialysis patients and 39 specimens from continuous ambulatory peritoneal dialysis patients (CAPD). All patients with serum PTH levels within or below the normal range had low or normal bone turnover. Values of serum PTH above 450 pg/mL were 100% and 95.5% specific for high bone turnover in hemodialysis and CAPD patients, respectively. Values of serum PTH between 65 and 450 pg/mL had worse predictive value positive in CAPD patients (48.6% to 78.6%) than in hemodialysis patients (67.3% to 87.1%). When other characteristics of the patients were taken into consideration, only age in hemodialysis patients and serum ionized calcium in CAPD patients improved the predictive value of serum PTH. All hemodialysis patients younger than 45 years of age with serum PTH levels above 65 pg/mL (n = 15) had high bone turnover, and CAPD patients with low or normal bone turnover had higher serum ionized calcium. However, overall, bone turnover could not be predicted by serum PTH measurements in 30% of hemodialysis and 51.3% of CAPD patients. The data suggest that for patients with serum PTH levels between 65 and 450 pg/mL, bone biopsies are indicated to precisely assess bone turnover prior to initiation of vitamin D therapy.
随着动力缺失性骨病的发病率不断上升，在对慢性透析患者进行维生素D治疗之前，确定其骨转换水平至关重要。为了评估血清甲状旁腺激素（PTH）水平对骨转换的预测价值，我们在79例接受了一或两次骨活检的患者中，单独或联合其他变量，测定了血清PTH的敏感性、特异性和阳性预测值。血清PTH水平通过放射免疫分析法测定，并在骨活检时获取。根据骨激活频率的值，将患者分为（1）低或正常骨转换和（2）高骨转换两类。其中有57份活检标本取自血液透析患者，39份标本取自持续性非卧床腹膜透析（CAPD）患者。所有血清PTH水平在正常范围内或低于正常范围的患者，其骨转换均为低或正常。血清PTH值高于450 pg/mL时，对血液透析患者和CAPD患者高骨转换的特异性分别为100%和95.5%。血清PTH值在65至450 pg/mL之间时，CAPD患者的阳性预测值（48.6%至78.6%）比血液透析患者（67.3%至87.1%）更差。当考虑患者的其他特征时，仅血液透析患者的年龄和CAPD患者的血清离子钙可提高血清PTH的预测价值。所有年龄小于45岁且血清PTH水平高于65 pg/mL的血液透析患者（n = 15）均有高骨转换，而骨转换低或正常的CAPD患者血清离子钙更高。然而，总体而言，30%的血液透析患者和51.3%的CAPD患者无法通过血清PTH测量预测骨转换。数据表明，对于血清PTH水平在65至450 pg/mL之间的患者，在开始维生素D治疗之前，建议进行骨活检以精确评估骨转换。
