| leuk {SMPracticals} | R Documentation |
Survival Times and White Blood Counts for Leukaemia Patients
Description
A data frame of data from 33 leukaemia patients.
Usage
data(leuk)Format
A data frame with 33 observations on the following 3 variables.
- wbc
white blood cell count
- ag
a test result, '"present"' or '"absent"'
- time
survival time in weeks
Details
Survival times are given for 33 patients who died from acute myelogenous leukaemia. Also measured was the patient's white blood cell count at the time of diagnosis. The patients were also factored into 2 groups according to the presence or absence of a morphologic characteristic of white blood cells. Patients termed AG positive were identified by the presence of Auer rods and/or significant granulation of the leukaemic cells in the bone marrow at the time of diagnosis.
Source
Feigl, P. and Zelen, M. (1965) Estimation of exponential survival probabilities with concomitant information. Biometrics, 21, 826–838.
References
Cox, D. R. and Oakes, D. (1984) Analysis of Survival Data. Chapman & Hall, p. 9.
Davison, A. C. (2003) Statistical Models. Cambridge University Press. Page 542.
Examples
data(leuk)
library(survival)
plot(survfit(Surv(time) ~ ag, data = leuk), lty = 2:3, col = 2:3)
# fit of exponential model
summary(glm(time~ag+log10(wbc),data=leuk,family=Gamma(log)),dispersion=1)
# now Cox models
leuk.cox <- coxph(Surv(time) ~ ag + log(wbc), leuk)
summary(leuk.cox)