R: Survival Times and White Blood Counts for Leukaemia Patients
leuk
R Documentation
Survival Times and White Blood Counts for Leukaemia Patients
Description
A data frame of data from 33 leukaemia patients.
Usage
leuk
Format
A data frame with columns:
wbc
white blood 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
Cox, D. R. and Oakes, D. (1984) Analysis of Survival Data.
Chapman & Hall, p. 9.
Taken from
Feigl, P. & Zelen, M. (1965) Estimation of exponential survival
probabilities with concomitant information.
Biometrics21, 826–838.
References
Venables, W. N. and Ripley, B. D. (2002)
Modern Applied Statistics with S. Fourth edition. Springer.
Examples
library(survival)
plot(survfit(Surv(time) ~ ag, data = leuk), lty = 2:3, col = 2:3)
# now Cox models
leuk.cox <- coxph(Surv(time) ~ ag + log(wbc), leuk)
summary(leuk.cox)
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> library(MASS)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/MASS/leuk.Rd_%03d_medium.png", width=480, height=480)
> ### Name: leuk
> ### Title: Survival Times and White Blood Counts for Leukaemia Patients
> ### Aliases: leuk
> ### Keywords: datasets
>
> ### ** Examples
>
> library(survival)
> plot(survfit(Surv(time) ~ ag, data = leuk), lty = 2:3, col = 2:3)
>
> # now Cox models
> leuk.cox <- coxph(Surv(time) ~ ag + log(wbc), leuk)
> summary(leuk.cox)
Call:
coxph(formula = Surv(time) ~ ag + log(wbc), data = leuk)
n= 33, number of events= 33
coef exp(coef) se(coef) z Pr(>|z|)
agpresent -1.0691 0.3433 0.4293 -2.490 0.01276 *
log(wbc) 0.3677 1.4444 0.1360 2.703 0.00687 **
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
exp(coef) exp(-coef) lower .95 upper .95
agpresent 0.3433 2.9126 0.148 0.7964
log(wbc) 1.4444 0.6923 1.106 1.8857
Concordance= 0.726 (se = 0.065 )
Rsquare= 0.377 (max possible= 0.994 )
Likelihood ratio test= 15.64 on 2 df, p=0.0004014
Wald test = 15.06 on 2 df, p=0.0005365
Score (logrank) test = 16.49 on 2 df, p=0.0002629
>
>
>
>
>
> dev.off()
null device
1
>