[Value of serum alkaline phosphatase for predicting 2-year fracture in patients with chronic kidney disease on dialysis].

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.