Weighted Youden index and its two-independent-sample comparison based on weighted sensitivity and specificity  

作　　者：LI Dan-ling SHEN Frank YIN Yue PENG Jun-xiang CHEN Ping-yan 

机构地区：[1]Department of Biostatistics, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China [2]Shanghai Roche Pharmaceuticals Ltd., Roche ProductDevelopment in Asia Pacific, Shanghai 201203, China

出　　处：《Chinese Medical Journal》2013年第6期1150-1154,共5页中华医学杂志（英文版）

基　　金：This work was supported by the grants from the National Natural Science Foundation of China （No. 30972554） and the Natural Science Foundation of Guangdong Province （No. 9 ! 5180200400001）.

摘　　要：Background Most indices for evaluating a diagnostic test can be expressed as functions of sensitivity （SEN） and specificity （SPE）. Practically, all existing methods suffer from the inability to weight sensitivity and specificity relative to their importance. In this paper, we developed a novel index, the weighted Youden index, that allows Youden index to be a combination of sensitivity and specificity with user-defined weights. Methods The weighted Youden index Jw is defined as Jw=2（wxSEN＋（1-w）SPE）-I （0 〈w 〈1）. It has three properties： （1） the sum of the weights which are attached to sensitivity and specificity should be equal to 1; （2） the range of Jw should be within [-1, 1], which is the range of the Youden index J; （3） Jw should be equal to J when sensitivity and specificity have equal weights. According to the central limit theorem, we obtain the standard error of Jw, and propose a statistical inference method to compare two weighted Youden indices. The monotonicity of the test statistic was discussed. Results An example of comparing two diagnostic tests for pheochromocytoma was used to demonstrate the weighted Youden index method. Weighted Youden index, the confidence interval for each test and the hypothesis test of comparing two independent diagnostic tests were presented. Assigning the weights is essential to the weighted Youden index approach. Conclusion The weighted Youden index can broaden further research in weighting sensitivity and specificity exp ts applications in diagnostic test development and motivate icitly.Background Most indices for evaluating a diagnostic test can be expressed as functions of sensitivity （SEN） and specificity （SPE）. Practically, all existing methods suffer from the inability to weight sensitivity and specificity relative to their importance. In this paper, we developed a novel index, the weighted Youden index, that allows Youden index to be a combination of sensitivity and specificity with user-defined weights. Methods The weighted Youden index Jw is defined as Jw=2（wxSEN＋（1-w）SPE）-I （0 〈w 〈1）. It has three properties： （1） the sum of the weights which are attached to sensitivity and specificity should be equal to 1; （2） the range of Jw should be within [-1, 1], which is the range of the Youden index J; （3） Jw should be equal to J when sensitivity and specificity have equal weights. According to the central limit theorem, we obtain the standard error of Jw, and propose a statistical inference method to compare two weighted Youden indices. The monotonicity of the test statistic was discussed. Results An example of comparing two diagnostic tests for pheochromocytoma was used to demonstrate the weighted Youden index method. Weighted Youden index, the confidence interval for each test and the hypothesis test of comparing two independent diagnostic tests were presented. Assigning the weights is essential to the weighted Youden index approach. Conclusion The weighted Youden index can broaden further research in weighting sensitivity and specificity exp ts applications in diagnostic test development and motivate icitly.

关 键 词：Youden index diagnostic tests WEIGHTS sensitivity SPECIFICITY 

分 类 号：R311[医药卫生—基础医学]