Validity of the reduced-sample insulin modified frequently-sampled intravenous glucose tolerance test using the nonlinear regression approach
Validity of the reduced-sample insulin modified frequently-sampled intravenous glucose tolerance test using the nonlinear regression approach
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DOI：
10.1016/j.metabol.2008.09.017
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发表时间：
2009-02-01
影响因子：
9.8
通讯作者：
Tulloch-Reid, Marshall K.
中科院分区：
文献类型：
--
作者：
Sumner, Anne E.;Luercio, Marcella F.;Tulloch-Reid, Marshall K.
在非裔美国人中，胰岛素敏感性指数（S-l）和胰岛素对葡萄糖的急性反应的产物——性格指数与11q染色体有关。这种联系是通过最小模型的非线性回归方法计算的S-l和来自减少样本胰岛素修改的频繁采样静脉葡萄糖耐量试验（减少样本im - fsigt）的数据确定的。然而，利用reduce - sample - im - fsigt数据计算S-l的非线性回归方法不仅不准确，而且在胰岛素抵抗受试者中失败率很高，因此受到了挑战。我们的目标是利用最小模型的非线性回归方法确定reduce - sample - im - fsigt的准确性和故障率。以Full- sample - im - fsigt协议中的S-l为标准，并使用最小模型的非线性回归方法，比较了Full- sample - im - fsigt协议和reduce - sample - im - fsigt协议中的S-l之间的一致性。100名非裔美国人(体重指数，31.3 +/- 7.6 kg/m(2)[平均值+/- SD]；范围，19.0-56.9 kg/m(2))有fsigt。基线时给予葡萄糖（0.3 g/kg）。胰岛素输注时间为20 ~ 25分钟（胰岛素总剂量0.02 U/kg）。对于Full-Sample-IM-FSIGT， S-l是根据在-1、1、2、3、4、5、6、7、8、10、12、14、16、19、22、23、24、25、27、30、40、50、60、70、80、90、100、120、150和180分钟采集的葡萄糖和胰岛素样品计算的。对于Reduced-Sample-FSIGT， S-l是根据黑体显示的时间点计算的。通过Spearman相关、一致性和Bland-Altman方法确定一致性。此外，对于这两种方案，种群被划分为s - 1三类。根据Full-Sample-IM-FSIGT的最低分位数S来定义胰岛素抵抗。采用秩序和kappa统计量比较各分位受试者的分布。我们发现，通过Reduced-Sample-IM-FSIGT对s - 1的分辨失败率为3%（3/100）。其余97名受试者的全样本和缩减样本im - fsigt S-l分别为：3.76 +/- 2.41 L mU(-1) min(-1)（范围0.58 ~ 14.50）和4.29 +/- 2.89 L mU(-1) min(-1)（范围0.52 ~ 14.42）；相对误差21% +/- 18%；Spearman r = 0.97；一致性为0.94 （P < 0.001）。经对数变换后，Bland-Altman的一致性极限分别为-0.29和0.53。胰岛素抵抗型和胰岛素敏感型种群分布的一致性为92%，kappa为0.82 +/- 0.06。使用非线性回归方法和来自广泛胰岛素敏感性受试者的reduce - sample - im - fsigt数据，仅3%的受试者无法解决s - 1。协议之间S-l等级顺序的一致和保持，支持在临床研究中使用最小模型和reduce - sainple - im - fsigt的非线性回归方法。Elsevier Inc.出版。
The disposition index, the product of the insulin sensitivity index (S-l) and the acute insulin response to glucose, is linked in African Americans to chromosome 11q. This link was determined with S-l calculated with the nonlinear regression approach to the minimal model and data from the reduced-sample insulin-modified frequently-sampled intravenous glucose tolerance test (Reduced-Sample-IM-FSIGT). However, the application of the nonlinear regression approach to calculate S-l using data from the Reduced-Sample-IM-FSIGT has been challenged as being not only inaccurate but also having a high failure rate in insulin-resistant subjects. Our goal was to determine the accuracy and failure rate of the Reduced-Sample-IM-FSIGT using the nonlinear regression approach to the minimal model. With S-l from the Full-Sample-IM-FSIGT considered the standard and using the nonlinear regression approach to the minimal model, we compared the agreement between S-l from the Full- and Reduced-Sample-IM-FSIGT protocols. One hundred African Americans (body mass index, 31.3 +/- 7.6 kg/m(2) [mean +/- SD]; range, 19.0-56.9 kg/m(2)) had FSIGTs. Glucose (0.3 g/kg) was given at baseline. Insulin was infused from 20 to 25 minutes (total insulin dose, 0.02 U/kg). For the Full-Sample-IM-FSIGT, S-l was calculated based on the glucose and insulin samples taken at -1, 1, 2, 3, 4, 5, 6, 7, 8,10, 12, 14, 16, 19, 22, 23, 24, 25, 27, 30, 40, 50, 60, 70 80, 90 100 120, 150, and 180 minutes. For the Reduced-Sample-FSIGT, S-l was calculated based on the time points that appear in bold. Agreement was determined by Spearman correlation, concordance, and the Bland-Altman method. In addition, for both protocols, the population was divided into tertiles S-l. Insulin resistance was defined by the lowest tertile of S, from the Full-Sample-IM-FSIGT. The distribution of subjects across tertiles was compared by rank order and kappa statistic. We found that the rate of failure of resolution of S-l by the Reduced-Sample-IM-FSIGT was 3% (3/100). For the remaining 97 subjects, S-l for the Full- and Reduced-Sample-IM-FSIGTs were as follows: 3.76 +/- 2.41 L mU(-1) min(-1) (range, 0.58-14.50) and 4.29 +/- 2.89 L mU(-1) min(-1) (range, 0.52-14.42); relative error, 21% +/- 18%; Spearman r = 0.97; and concordance, 0.94 (both P < .001). After log transformation, the Bland-Altman limits of agreement were -0.29 and 0.53. The exact agreement for distribution of the population in the insulin-resistant tertile vs the insulin-sensitive tertiles was 92%, kappa of 0.82 +/- 0.06. Using the nonlinear regression approach and data from the Reduced-Sample-IM-FSIGT in subjects with a wide range of insulin sensitivity, failure to resolve S-l occurred in only 3% of subjects. The agreement and maintenance of rank order of S-l between protocols support the use of the nonlinear regression approach to the minimal model and the Reduced-Sainple-IM-FSIGT in clinical studies. Published by Elsevier Inc.