Biostatistics III in R

Author

Code by Annika Tillander, Andreas Karlsson and Mark Clements

Exercise 1: Life tables and Kaplan-Meier estimates of survival

(a) Hand calculation: Life table and Kaplan-Meier estimates of survival

The results are contained in an Excel file and are also shown in the R output below.

(b) Using R to validate the hand calculations done in part 1 (a)

First, load the biostat3 library:

Following are the life table estimates. Note that in the lectures, when we estimated all-cause survival, there were 8 deaths in the first interval. One of these died of a cause other than cancer so in the cause-specific survival analysis we see that there are 7 ‘deaths’ and 1 censoring (Stata uses the term ‘lost’ for lost to follow-up) in the first interval.

Following is a table of Kaplan-Meier estimates. Although it’s not clear from the table, the person censored (lost) at time 2 was at risk when the other person dies at time 2. On the following is a graph of the survival function.