Description

A randomized clinical trial in which both survival and longitudinal data were collected to compare the efficacy and safety of two antiretroviral drugs, namely ddI (didanosine) and ddC (zalcitabine), in treating HIV-infected patients intolerant or failing zidovudine (AZT) therapy.

Format

A data frame with 1405 observations on the following 12 variables.

ID

patient ID, there are 467 patients in total.

Time

survival time, i.e. time to death or censoring.

death

death indicator: 0 denotes censoring; 1 denotes death.

obstime

time points at which the longitudinal measurements, i.e. CD4 cell counts, are recorded.

CD4

CD4 cell counts measured at obstime.

drug

drug indicator with two levels: ddI and ddC.

gender

gender indicator with two levels: male and female.

prevDiag

AIDS diagnosis at study entry indicator with two levels: AIDS and noAIDS.

AZT

AZT intolerance/failure indicator with two levels: intolerance and failure.

start

same with obstime, starting time of the interval which contains the time of the CD4 cell count measurement.

stop

ending time of the interval which contains the time of the CD4 cell count measurement.

event

event indicator suggesting whether the event-of-interest, i.e. death, happens in the interval given by start and stop.

Source

Goldman, A., Carlin, B., Crane, L., Launer, C., Korvick, J., Deyton, L. and Abrams, D. (1996) Response of CD4+ and clinical consequences to treatment using ddI or ddC in patients with advanced HIV infection. Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology 11, 161–169.

References

Guo, X. and Carlin, B. (2004) Separate and joint modeling of longitudinal and event time data using standard computer packages. The American Statistician 58, 16–24.

Xu, C., Baines, P. D. and Wang, J. L. (2014) Standard error estimation using the EM algorithm for the joint modeling of survival and longitudinal data. Biostatistics 15, 731–744

Examples