Use of the concordance index for predictors of censored survival data. (August 2018)

• Record Type: Journal Article
• Authors: Brentnall, Adam R; Cuzick, Jack
• Is Part Of: Statistical methods in medical research. Volume 27:Number 8(2018)
• Page Start: 2359
• Page End: 2373
• Publication Date: 2018-08
• Subjects: Biomarkers -- C-index -- discrimination -- Pareto model -- proportional-hazards model -- survival analysis; Medicine -- Research -- Statistical methods -- Periodicals; Research -- Periodicals; Review Literature -- Periodicals; Statistics -- methods -- Periodicals; Médecine -- Recherche -- Méthodes statistiques -- Périodiques; 610.727
• DOI: 10.1177/0962280216680245
• Languages: English
• ISSNs: 0962-2802

Abstract

The concordance index is often used to measure how well a biomarker predicts the time to an event. Estimators of the concordance index for predictors of right-censored data are reviewed, including those based on censored pairs, inverse probability weighting and a proportional-hazards model. Predictive and prognostic biomarkers often lose strength with time, and in this case the aforementioned statistics depend on the length of follow up. A semi-parametric estimator of the concordance index is developed that accommodates converging hazards through a single parameter in a Pareto model. Concordance index estimators are assessed through simulations, which demonstrate substantial bias of classical censored-pairs and proportional-hazards model estimators. Prognostic biomarkers in a cohort of women diagnosed with breast cancer are evaluated using new and classical estimators of the concordance index.