Measured versus estimated glomerular filtration rate in the Calvert equation: influence on carboplatin dosing
Measured versus estimated glomerular filtration rate in the Calvert equation: influence on carboplatin dosing
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DOI：
10.1007/s002800000260
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发表时间：
2001-05-01
影响因子：
3
通讯作者：
Lindley, C
中科院分区：
文献类型：
--
作者：
Donahue, A;McCune, JS;Lindley, C
目的。通过使用Calvert或Chatelut方程来估计卡铂清除量，卡铂经常被用来在血药浓度-时间曲线(AUC)下达到所需的面积。准确测定肾小球滤过率(GFR)是使用Calvert方程正确计算卡铂清除量所必需的。在临床实践中，Cockcroft-Gault公式经常被用来估计GFR，但据报道，这种做法低估和高估了卡铂的清除量。这项试验的目的是比较使用Chatelut方程和四种不同的GFR测定方法测定卡铂的清除度，包括TC-99m-DTPA、Cockcroft-Gault公式、24小时尿液采集和2小时尿液采集。方法：对21例未经治疗的广泛期小细胞肺癌患者的卡铂清除率进行评估。采用99m-DTPA、Cockcroft-Gault公式、24小时尿液和2小时尿液测定肾小球滤过率。用酶法测定血清和尿肌酐浓度。然后，根据卡尔弗特方程，通过在四个GFR测定中分别增加25来计算卡铂清除量，该方程式表明卡铂清除量等于GFR+25(非肾脏清除量)。卡铂清除量也用Chatelut方程估算。用Friedman‘s检验和后Wilcoxon签名等级检验对卡铂清除率的五种测定方法进行比较。计算每个卡铂清除量测定的精密度和偏倚，假设TC-99m-DTPA提供最准确的GFR测量。结果。在估计卡铂清除量的五种方法之间发现有统计学意义的差异(P<；0.001)。用~(99m)Tc-DTPA计算的卡铂清除量与Chatelut方程、Cockcroft-Gault公式或2小时尿液采集结果无差异。Chatelut方程提供了比2小时尿液采集更高的精确度和更小的偏差(中位精确度分别为20%和30%，中位偏差分别为-1%和-18%)。结论。与Tc-99m-DTPA相比，Chatelut方程比Cockcroft-Gault公式、2小时尿液采集和24小时尿液采集更准确地估计卡铂清除量。卡铂清除量的后三个估算值存在较大的负偏倚，可能导致卡铂剂量不足。
Purpose. Carboplatin is frequently dosed to achieve a desired area under the plasma concentration-time curve (AUC) by using the Calvert or Chatelut equations to estimate carboplatin clearance. Accurate determination of glomerular filtration rate (GFR) is necessary to correctly calculate carboplatin clearance using the Calvert equation. In clinical practice, the Cockcroft-Gault formula is frequently used to estimate GFR, but this practice has been reported to under- and overestimate carboplatin clearance. The purpose of this trial was to compare determinations of carboplatin clearance using the Chatelut equation and four separate GFR determinations, including Tc-99m-DTPA, the Cockcroft-Gault formula, a 24-h urine collection and a 2-h urine collection. Methods: Carboplatin clearance was estimated in 21 previously untreated extensive-stage small-cell lung cancer patients. GFR was determined using Tc-99m-DTPA, the Cockcroft-Gault formula, 24-h urine collection and 2-h urine collection. Serum and urine creatinine concentrations were measured using enzymatic assays. The carboplatin clearance was then calculated by individually adding 25 to the four GFR determinations based on the Calvert equation, which states that carboplatin clearance equals GFR + 25 (nonrenal clearance). The carboplatin clearance was also estimated using the Chatelut equation. The five determinations of carboplatin clearance were compared using Friedman's test and post-hoc Wilcoxon signed rank tests. Precision and bias for each carboplatin clearance determination were calculated assuming that Tc-99m-DTPA provided the most accurate measure of GFR. Results. A statistically significant difference was found between the five methods of estimating carboplatin clearance (P < 0.001). No difference was found between carboplatin clearance calculated using Tc-99m-DTPA and the Chatelut equation, the Cockcroft-Gault formula or the 2-h urine collection. The Chatelut equation provided more precision and less bias than the 2-h urine collection (median precision 20% and 30%, median bias -1% and -18%, respectively). Conclusion. Compared to Tc-99m-DTPA, the Chatelut equation more accurately estimates carboplatin clearance than the Cockcroft-Gault formula, the 2-h urine collection and the 24-h urine collection. The greater negative bias found for the latter three estimates of carboplatin clearance could result in underdosing of carboplatin.