epilepsy {JSM}

CBZ versus LTG in Epilepsy Patients

Description

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).

Format

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.

Source

Marson, A. G., AI-Kharusi, A. M., Alwaidh, M., Appleton, R., Baker, G. A., Chadwick, D. W., Cramp, C., Cockerell, O. C. Cooper, P. N., Doughty, J. et al. (2007) The SANAD study of effectiveness of carbamazepine, gabapentin, lamotrigine, oxcarbazepine, or topiramate for treatment of partial epilepsy: an unblinded randomised controlled trial. The Lancet 369, 1000–1015.

References

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.

Examples

head(epilepsy)