title: Estimation of an accuracy index of a diagnostic biomarker when the reference biomarker is continuous and measured with error.
abstract: New biomarkers continue to be developed for the purpose of diagnosis, and their diagnostic performances are typically compared with an existing reference biomarker used for the same purpose. Considerable amounts of research have focused on receiver operating characteristic curves analysis when the reference biomarker is dichotomous. In the situation where the reference biomarker is measured on a continuous scale and dichotomization is not practically appealing, an index was proposed in the literature to measure the accuracy of a continuous biomarker, which is essentially a linear function of the popular Kendall's tau. We consider the issue of estimating such an accuracy index when the continuous reference biomarker is measured with errors. We first investigate the impact of measurement errors on the accuracy index, and then propose methods to correct for the bias due to measurement errors. Simulation results show the effectiveness of the proposed estimator in reducing biases. The methods are exemplified with hemoglobin A1c measurements obtained from both the central lab and a local lab to evaluate the accuracy of the mean data obtained from the metered blood glucose monitoring against the centrally measured hemoglobin A1c from a behavioral intervention study for families of youth with type 1 diabetes.
authors.affiliation: a College of Applied Sciences , Beijing University of Technology , Beijing , China.
authors.forename: Mixia
authors.initials: M
authors.lastname: Wu
authors.affiliation: b Biostatistics and Bioinformatics Branch , Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , Maryland , USA.
authors.forename: Dianchen
authors.initials: D
authors.lastname: Zhang
authors.affiliation: b Biostatistics and Bioinformatics Branch , Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , Maryland , USA.
authors.forename: Aiyi
authors.initials: A
authors.lastname: Liu
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D000068598:Data Accuracy; D003627:Data Interpretation, Statistical; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D012372:ROC Curve; D012015:Reference Standards
chemical_list: D015415:Biomarkers; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Bias; Kendall’s tau; diagnostic accuracy; measurement error; reliability coefficient