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Publication Information

PubMed ID
Public Release Type
Journal
Publication Year
2019
Affiliation
Statistics Group, RAND Corporation, Santa Monica, California.; Department of Biostatistics, Harvard University, Boston, Massachusetts.; Department of Biomedical Data Science, Stanford University, Stanford, California.
Authors
Parast Layla, Cai Tianxi, Tian Lu
Studies

Abstract

The development of methods to identify, validate, and use surrogate markers to test for a treatment effect has been an area of intense research interest given the potential for valid surrogate markers to reduce the required costs and follow-up times of future studies. Several quantities and procedures have been proposed to assess the utility of a surrogate marker. However, few methods have been proposed to address how one might use the surrogate marker information to test for a treatment effect at an earlier time point, especially in settings where the primary outcome and the surrogate marker are subject to censoring. In this paper, we propose a novel test statistic to test for a treatment effect using surrogate marker information measured prior to the end of the study in a time-to-event outcome setting. We propose a robust nonparametric estimation procedure and propose inference procedures. In addition, we evaluate the power for the design of a future study based on surrogate marker information. We illustrate the proposed procedure and relative power of the proposed test compared to a test performed at the end of the study using simulation studies and an application to data from the Diabetes Prevention Program.