A STUDY ON COX REGRESSION PROCEDURES IN SURVIVAL ANALYSIS

Mr.M.Palanivel

Volume : VI, Issue : XII, December - 2016

A STUDY ON COX REGRESSION PROCEDURES IN SURVIVAL ANALYSIS

Mr. M. Palanivel

Abstract :

The term "survival analysis" pertains to a statistical approach designed to take into account the amount of time an experimental unit contributes to a study. That is, it is the study of time between entry into observation and a subsequent event. In logistic regression, we were interested in studying how risk factors were associated with presence or absence of disease. Sometimes, though, we are interested in how a risk factor or treatment affects time to disease or some other event. Or we may have study dropout, and therefore subjects who we are not sure if they had disease or not. In these cases, logistic regression is not appropriate. This effectively creates a timevarying coefficient that is easily estimated in software such as SAS and R. However, the usual programming statements for survival estimation are not directly applicable. Unique data manipulation and syntax is required, but is not well documented for either software. This paper covers a tutorial in survival estimation for the time–varying coefficient model, implemented in SAS and R. We provide a macro coxtvc to facilitate estimation in SAS where the current functionality is more limited. The macro is validated in simulated data and illustrated in an application. ABSTRACT