Power and Sample Size Calculations for SNP Association Studies with Censored Time-to-Event Outcomes

• Activity Number: 133
• Type: Contributed
• Date/Time: Monday, August 1, 2011 : 8:30 AM to 10:20 AM
• Sponsor: ENAR
• Author(s): Kouros Owzar*+ and Zhiguo Li and Sin-Ho Jung
• Companies: Duke University and Duke University and Duke University
• Keywords: SNP ; survival ; censoring ; power ; sample size ; score test

Abstract

For many clinical studies in cancer, germline DNA is prospectively collected for the purpose of identifying or validating Single Nucleotide Polymorphisms (SNP) associated with clinical outcomes. The primary clinical endpoint for many of these studies are time-to-event outcomes such as time of death or disease progression which are subject to censoring mechanisms. The Cox score test can be readily employed to test the association between a SNP and the outcome of interest. In addition to the effect and sample size, and censoring distribution, the power of the test will depend on the underlying genetic risk model and the distribution of the risk allele. We conduct a comprehensive review of the statistical power of the Cox score test under a variety of genetic risk models and risk allele distributions. Asymptotic formulas for power and sample size calculation will be presented.