Luo Jingqin, Xiong Chengjie
Division of Biostatistics, Washington University in St. Louis, St. Louis, MO, 63110.
Commun Stat Simul Comput. 2013 Jan;42(6):1213-1234. doi: 10.1080/03610918.2012.661906.
Directly relating to sensitivity and specificity and providing an optimal cut-point which maximizes overall classification effectiveness for diagnosis purpose, the Youden index has been frequently utilized in biomedical diagnosis practice. Current application of the Youden index is limited to two diagnostic groups. However, there usually exists a transitional intermediate stage in many disease processes. Early recognition of this intermediate stage is vital to open an optimal window for therapeutic intervention. In this paper, we extend the Youden index to assess diagnostic accuracy when there are three ordinal diagnostic groups. Parametric and nonparametric methods are presented to estimate the optimal Youden index, the underlying optimal cut-points and the associated confidence intervals. Extensive simulation studies covering representative distributional assumptions are reported to compare performance of the proposed methods. A real example illustrates the usefulness of the Youden index in evaluating discriminating ability of diagnostic tests.
约登指数直接与敏感性和特异性相关，并提供一个最佳切点，以最大化诊断目的的整体分类效能，因此在生物医学诊断实践中经常被使用。约登指数目前的应用仅限于两个诊断组。然而，在许多疾病过程中通常存在一个过渡的中间阶段。早期识别这个中间阶段对于打开最佳治疗干预窗口至关重要。在本文中，我们扩展了约登指数，以评估存在三个有序诊断组时的诊断准确性。提出了参数和非参数方法来估计最佳约登指数、潜在的最佳切点和相关的置信区间。报告了涵盖代表性分布假设的广泛模拟研究，以比较所提出方法的性能。一个实际例子说明了约登指数在评估诊断测试鉴别能力方面的有用性。
