A randomised control trial, the SANAD (standard and new antiepileptic drugs) study, in which both survival and longitudinal data were collected to investigate the effect of drug titration on the relative effects of two antiepileptic drugs, namely CBZ
(carbamazepine, a standard drug) and LTG
(lamotrigine, a new drug), on treatment failure. Treatment failure, i.e. withdrawal of the randomized drug, is the event of interest. Two main reasons for withdrawal are unacceptable adverse effects (UAE) and inadequate seizure control (ISC).
A data frame with 2797 observations on the following 16 variables.
ID
patient ID, there are 605 patients in total.
Time
survival time, i.e. time to withdrawal or censoring.
withdraw
withdrawal indicator: 0 denotes censoring; 1 denotes withdrawal.
withdrawUAE
withdrawal due to UAE indicator: 1 denotes withdrawal due to UAE; 0 otherwise.
withdrawISC
withdrawal due to ISC indicator: 1 denotes withdrawal due to ISC; 0 otherwise.
obstime
time points at which the longitudinal measurements, i.e. the dose, are recorded.
dose
calibrated dose measured at obstime
.
drug
drug indicator with two levels: CBZ
and LTG
.
age
age of patient at study entry.
gender
gender indicator with two levels: male
and female
.
disab
learning disability indicator with two levels: No
and Yes
.
start
same with obstime
, starting time of the interval which contains the time of the dose measurement.
stop
ending time of the interval which contains the time of the dose measurement.
event
event indicator suggesting whether the event-of-interest, i.e. withdrawal, happens in the interval given by start
and stop
.
eventUAE
event indicator suggesting whether the event-of-interest, i.e. withdrawal due to UAE, happens in the interval given by start
and stop
.
eventISC
event indicator suggesting whether the event-of-interest, i.e. withdrawal due to ISC, happens in the interval given by start
and stop
.
Williamson P. R., Kolamunnage-Dona R., Philipson P. and Marson A. G. (2008) Joint modelling of longitudinal and competing risks data. Statistics in Medicine 27, 6426--6438.
# NOT RUN {
head(epilepsy)
# }
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