Renal Research Institute, New York, NY 10128, USA.
Blood Purif. 2013;35(1-3):133-8. doi: 10.1159/000346099. Epub 2013 Jan 22.
BACKGROUND/AIM: Citrate anticoagulation in hemodialysis (HD) is increasingly drawing attention in the nephrology community. One of the major deterrents to a more widespread use are the monitoring requirements for fear of systemic calcium derangements. Means of accurately predicting systemic ionized calcium (iCa) may help to overcome this challenge. We have previously presented a mathematical model of regional citrate anticoagulation (RCA) to address this need. Here, we present a refined model and show results in an independent validation cohort of maintenance HD patients on Citrasate®, a calcium- and citrate-containing dialysate.
A hybrid RCA model was developed, comprising the previously published 'native' RCA model and a statistical correction based on levels of alkaline phosphatase as a marker of bone turnover. The model was validated in 120 patients on Citrasate, a dialysate containing 0.8 mmol/l citrate and 1.125 mmol/l calcium. Systemic iCa was measured at the beginning and end of one HD treatment in each subject. Serum iCa predictions were compared between our previously published model and the new hybrid model.
On average, the hybrid model predicted end-HD systemic iCa with an error (predicted - measured) of 0.028 mmol/l, compared to -0.051 mmol/l with the previously published model. There were only 4 subjects out of the 120 analyzed in whom the prediction error was <-0.1 mmol/l, and only 6 in whom the error was >+0.1 mmol/l (max: +0.13 mmol/l).
This study demonstrates that the novel hybrid model is an improvement over the previously published model and that it is capable of predicting end-dialysis systemic iCa levels with improved accuracy and precision even in a citrate dialysis setting which was much different from the original derivation cohort.
背景/目的：在肾脏病学领域，血液透析（HD）中的柠檬酸盐抗凝越来越受到关注。由于担心全身性钙紊乱，监测要求成为更广泛使用的主要障碍之一。准确预测系统离子钙（iCa）的方法可能有助于克服这一挑战。我们之前提出了一种局部柠檬酸盐抗凝（RCA）的数学模型来满足这一需求。在这里，我们提出了一个改进的模型，并在使用含有钙和柠檬酸盐的透析液 Citrasate®的维持性 HD 患者的独立验证队列中展示了结果。
开发了一种混合 RCA 模型，包括之前发表的“天然”RCA 模型和基于碱性磷酸酶水平的统计校正，碱性磷酸酶是骨转换的标志物。该模型在 120 名使用 Citrasate 的患者中进行了验证，Citrasate 含有 0.8mmol/l 柠檬酸盐和 1.125mmol/l 钙。在每个受试者的一次 HD 治疗的开始和结束时测量系统 iCa。将我们之前发表的模型和新的混合模型之间的血清 iCa 预测进行比较。
平均而言，混合模型预测终末 HD 系统 iCa 的误差（预测值-实测值）为 0.028mmol/l，而之前发表的模型为-0.051mmol/l。在分析的 120 名患者中，只有 4 名患者的预测误差< -0.1mmol/l，只有 6 名患者的误差> +0.1mmol/l（最大值：+0.13mmol/l）。
本研究表明，新型混合模型优于之前发表的模型，即使在与原始推导队列差异很大的柠檬酸盐透析环境中，它也能够更准确和精确地预测终末期系统 iCa 水平。
