Interval Estimation for the Youden Index and Optimal Cut‐Off Point in <scp>AUC</scp>‐Based Optimal Combinations of Multivariate Normal Biomarkers With Covariates

In this article, we present interval estimation methods for the Youden index and the optimal cut-off point in the context of AUC-based optimal combinations of multivariate normally distributed biomarkers, considering the presence of covariates. We propose a generalized pivotal confidence interval, a Bayesian credible interval, and several bootstrap confidence intervals for both the Youden index and its corresponding cut-off point. To evaluate the performance of these confidence and credible intervals, we conducted a Monte Carlo simulation study. Finally, we illustrate the proposed methods using a diabetic dataset.