Survival Analysis: From Square One to Square Two. Yin Bun Cheung, Ph.D. Paul Yip, Ph.D. Readings. Lecture structure. Basic concepts Kaplan-Meier analysis Cox regression Computer practice. time-to-event data failure-time data censored data (unobserved outcome). What’s in a name?.
Yin Bun Cheung, Ph.D.
Paul Yip, Ph.D.
1. Marital status & mortality
2. Medical treatments & tumor recurrence & mortality in cancer patients
3. Size at birth & developmental milestones in infants
In clinical trials:
1. Non-parametric method
2. Semi-parametric method
3. Parametric method
This lecture focuses on two commonly used methods
* d=death, c=censored, surv=survival
Expected death in group A at time i, assuming equality in survival:
EAi =no. at risk in group A i death i
total no. at risk i
Total expected death in group A: EA = EAi
The log rank test statistic is often approximated by
X2 = (OA-EA)2/EA+ (OB-EB)2/EB,
where OA & EA are the observed & expected number of deaths in group A, etc.
Log rank test preferred (PH true )
Breslow test preferred (non-PH)
A clinical trial of
stage I bladder tumor
Thiotepa vs Control
Data from StatLib
Two most important variables:
(coding depends on software)
chi2(1) = 1.52
Pr>chi2 = 0.22
for PH in model II
Ex 1. Cheung. Int J Epidemiol 2000;29:93-99.
Ex 2. Sauerbrei et al.J Clin Oncol 2000;18:94-101.
Ex 3. Cheung et al. Int J Epidemiol 2001;30:66-74.