Reclassification Calculations for Persons With Incomplete Follow-up

Abstract

Letters2 February 2010Reclassification Calculations for Persons With Incomplete Follow-upEwout W. Steyerberg, PhD and Michael J. Pencina, PhDEwout W. Steyerberg, PhDFrom Erasmus MC University Medical Center Rotterdam, Rotterdam 3015, the Netherlands; and Boston University, Boston, MA 02215.Search for more papers by this author and Michael J. Pencina, PhDFrom Erasmus MC University Medical Center Rotterdam, Rotterdam 3015, the Netherlands; and Boston University, Boston, MA 02215.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-152-3-201002020-00019 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:We applaud Cook and Ridker (1) for their clear discussion of reclassification measures and recent developments in judging the incremental value of a biomarker for prediction of outcome. A key area of application is in cardiovascular disease, in which the time horizon is typically 10 years. One important problem recognized by Cook and Ridker is that not all persons will have follow-up completed until 10 years. Kaplan–Meier curves and Cox regression analysis were introduced long ago to deal with such censored observations. Reclassification measures, such as the net reclassification index (NRI) (2), have been proposed for binary ...