Ddiabetic retinopathy
Partial results from a trial of laser coagulation for the treatment of diabetic retinopathy.
diabetic data(diabetic, package="survival")
A data frame with 394 observations on the following 8 variables.
idsubject id
laserlaser type: xenon or argon
ageage at diagnosis
eyea factor with levels of left right
trttreatment: 0 = no treatment, 1= laser
riskrisk group of 6-12
timetime to event or last follow-up
statusstatus of 0= censored or 1 = visual loss
The 197 patients in this dataset were a 50% random sample of the patients with "high-risk" diabetic retinopathy as defined by the Diabetic Retinopathy Study (DRS). Each patient had one eye randomized to laser treatment and the other eye received no treatment. For each eye, the event of interest was the time from initiation of treatment to the time when visual acuity dropped below 5/200 two visits in a row. Thus there is a built-in lag time of approximately 6 months (visits were every 3 months). Survival times in this dataset are therefore the actual time to blindness in months, minus the minimum possible time to event (6.5 months). Censoring was caused by death, dropout, or end of the study.
Huster, Brookmeyer and Self, Biometrics, 1989.
American Journal of Ophthalmology, 1976, 81:4, pp 383-396
# juvenile diabetes is defined as and age less than 20
juvenile <- 1*(diabetic$age < 20)
coxph(Surv(time, status) ~ trt + juvenile, cluster= id,
data= diabetic)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.