Define survival function, hazard functions, cumulative event function
Perform a Kaplan-Meier estimate
Perform, interpret, and identify assumptions of the logrank test
Define and calculate potential follow-up time
Calculate median survival time
Outline
Introduction to censored data
Outcome variable: time-to-event
Types of censored data
Assumption of uninformative censoring
Survival function and Kaplan-Meier estimator
Comparing groups: Log-rank test
Vittinghoff sections 3.1-3.5
Tutorial Paper Survival Analysis Part I: Basic concepts and first analyses by Clark, Bradburn, Love, Altman. British Journal of Cancer (2003) 89, 232 – 238
Lab
Learning Objectives
Calculate Kaplan-Meier estimates of survival probability over time
Plot survival curves for censored time-to-event data
Perform and interpret log-rank test
Define “informative” censoring
Exercises
Calculate the follow-up table for 6 MP patients in the leukemia study
Plot the Kaplan-Meier estimate of the follow-up table from 1. library(survminer) is recommendable.
What is the 75th percentile of survival times for the 6 MP group? For the Placebo group? This is the time that 75% of the patients survive.
Suppose you were instructed to cap follow-up times at 20 weeks. Re-do the Kaplan-Meier plot for both groups, and re-do the logrank test.
Give a hypothetical example of how censoring in this example might be “informative.”