Supplementary Material for: Serum Alkaline Phosphatase Level Predicts Cardiac Valve Calcification in Maintenance Hemodialysis Patients

Purpose: Cardiac valve calcification (CVC) is frequently occurred in maintenance hemodialysis (MHD) patients and is associated with cardiovascular and all-cause mortality. This study aimed to evaluate the relationships between risk factors and extent of CVC and further provide the treatment target in MHD patients. Methods: One hundred and forty-five patients who received MHD ≥3 months were enrolled. CVC was assessed by an echocardiographic, semi-quantitative manner called global cardiac calcium scoring system (GCCS), and demographic, clinical, and laboratory parameters including mineral metabolism markers were collected. Results: The average age of the patients was 50 ± 12 years, and 54.5% were men. The mean GCCS was 1.8 ± 2.4; 57.2% of patients had GCCS ≥1. Age, dialysis vintage, serum alkaline phosphatase (ALP), and intact parathyroid hormone levels were positively correlated with CVC, whereas serum albumin levels were negatively related to CVC, based on univariate analysis. With multivariate linear regression analysis, serum ALP was the only bone-derived biomarker that showed significant correlation with CVC. Serum ALP ≥232 U/L was a robust predictor of CVC and was associated with the likelihood of GCCS ≥1 (OR 3.92, 95% CI 1.37–11.2, p = 0.011). The decision tree model was used to identify ALP ≥232 U/L and age ≥60 years as important determinative variables in the prediction of CVC in MHD patients. Conclusion: Serum ALP level is significantly associated with CVC in MHD patients. ALP is suggested to be a promising interventional target for cardiovascular calcification in MHD patients.

研究目的：心脏瓣膜钙化（cardiac valve calcification, CVC）在维持性血液透析（maintenance hemodialysis, MHD）患者中高发，且与心血管疾病及全因死亡率密切相关。本研究旨在探讨MHD患者心脏瓣膜钙化的危险因素与钙化程度之间的关联，并进一步明确其治疗靶点。
研究方法：本研究纳入145例接受维持性血液透析≥3个月的患者。采用名为整体心脏钙化评分系统（global cardiac calcium scoring system, GCCS）的超声心动图半定量方法评估心脏瓣膜钙化情况，并收集患者的人口学特征、临床指标及实验室参数，包括矿物质代谢相关标志物。
研究结果：患者平均年龄为50±12岁，男性占比54.5%。整体心脏钙化评分系统（GCCS）平均得分为1.8±2.4；57.2%的患者GCCS评分≥1。单因素分析显示，年龄、透析龄、血清碱性磷酸酶（alkaline phosphatase, ALP）及全段甲状旁腺激素（intact parathyroid hormone）水平与CVC呈正相关，而血清白蛋白水平与CVC呈负相关。多因素线性回归分析显示，血清ALP是唯一与CVC存在显著相关性的骨源性生物标志物。血清ALP≥232 U/L是CVC的强有力预测因子，且与GCCS评分≥1的发生风险相关（比值比（OR）=3.92，95%置信区间（95% CI）：1.37~11.2，P=0.011）。决策树模型分析显示，ALP≥232 U/L与年龄≥60岁是预测MHD患者发生CVC的重要决定性变量。
研究结论：血清ALP水平与MHD患者的CVC显著相关。ALP有望成为MHD患者心血管钙化的潜在干预靶点。