Objective: To explore the value of baseline serum alkaline phosphatase (ALP) for predicting 2-year fracture in patients with chronic kidney disease (CKD) on maintenance dialysis.
Methods: A total of 139 patients with CKD undergoing maintenance dialysis in our hospital were enrolled in this study. According to the median serum ALP level, the patients were divided into high ALP and low ALP groups. The demographic and clinical data of the patients including dialysis duration, serum calcium level, serum phosphorus level, and serum intact parathyroid hormone level were recorded, and their bone mineral density of the femur and the lumbar spine was measured using dual energy X-ray absorptiometry. The patients were followed up for 2 years and fracture events were recorded. The risk factors of fracture were analyzed using logistic regression analysis, and their predictive value for fracture was analyzed using receiver-operating characteristic (ROC) curve.
Results: The mean baseline serum ALP level was 132.55±167.68 U/L in these patients, significantly higher than that in the normal population (t=2.816, P=0.006). Baseline serum ALP level was negatively correlated with the bone mineral density of the lumbar spine (r=-0.203, P=0.006) and the femur (r=-0.196, P=0.021). Fractures occurred in 21 (15.1%) of the patients during the 2-year follow-up, and the fracture rate was significantly higher in patients with high ALP levels. Logistic regression analysis identified serum ALP level as an independent risk factor of fracture (OR: 1.010, P=0.001, 95%CI: 1.004-1.016). The areas under the ROC curve were 0.900 and 0.768 for serum ALP level and intact parathyroid hormone level in predicting 2-year fractures, respectively.
Conclusions: Serum ALP may serve as a good indicator for predicting 2-year fractures in patients with CKD on maintenance dialysis.
目的: 探讨基线血碱性磷酸酶水平对维持性透析患者2年内骨折事件的预测价值。
方法: 纳入我院139例维持性透析患者，检测基线血碱性磷酸酶水平，以其结果中位数把患者分成两组，记录年龄、性别、透析龄、血钙、血磷、完整甲状旁腺激素等相关临床资料并以双能X线吸收法检查股骨及腰椎骨密度，记录2年内发生的骨折事件，以χ2检验比较两组患者的骨折发生率，以Logistic回归分析了解骨折的危险因素，以ROC曲线分析各基线值对骨折的预测价值。
结果: 基线血碱性磷酸酶平均为132.55±167.68 U/L，明显高于正常人群对照组（t:2.816, P=0.006）。基线血碱性磷酸酶值分别与腰椎（r=-0.203, P=0.006）及股骨（r=-0.196, P=0.021）骨密度均负相关。随访2年内共发生骨折事件21例（15.1%）。高血碱性磷酸酶值组2年内骨折发生率显著高于低血碱性磷酸酶值组。Logistic回归分析提示血碱性磷酸酶水平是骨折的独立危险因素（OR：1.010, P=0.001，95%CI：1.004-1.016）。血碱性磷酸酶及完整甲状旁腺素对骨折预测的ROC曲线下面积分别为0.900及0.768。
结论: 血碱性磷酸酶水平是透析患者2年内骨折发生的良好预测指标。
Keywords: alkaline phosphate; chronic kidney disease; fracture; maintenance dialysis.