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Youden Index and the optimal threshold for markers with mass at zero

2007; Wiley; Volume: 27; Issue: 2 Linguagem: Inglês

10.1002/sim.2993

1097-0258

Enrique F. Schisterman, David Faraggi, Benjamin Reiser, Jessica Hu,

Advanced Causal Inference Techniques

Abstract The Youden Index is often used as a summary measure of the receiver operating characteristic curve. It measures the effectiveness of a diagnostic marker and permits the selection of an optimal threshold value or cutoff point for the biomarker of interest. Some markers, while basically continuous and positive, have a spike or positive mass of probability at the value zero. We provide a flexible modeling approach for estimating the Youden Index and its associated cutoff point for such spiked data and compare it with the standard empirical approach. We show how this modeling approach can be adjusted to take covariate information into account. This approach is applied to data on the Coronary Calcium Score, a marker for atherosclerosis. Published in 2007 by John Wiley & Sons, Ltd.