This dataset gives the longitudinal observations of prothrombin index, a measure of liver function, for patients from a controlled trial into prednisone treatment of liver cirrhosis. Time-to-event information in the form of the event time and associated censoring indicator are also recorded along with a solitary baseline covariate - the allocated treatment arm in this instance. The data are taken from Andersen et al. (1993, p. 19) and were analyzed in Henderson et al. (2002). This is a subset of the full data where a number of variables were recorded both at entry and during the course of the trial.
data(liver)A data.frame in the unbalanced format with longitudinal observations
from 488 subjects. The columns are:
idinteger: number for patient identification.
prothrombininteger: prothrombin index measurement (%).
timenumeric: time of prothrombin index measurement (years).
treatmentinteger: patient treatment indicator. Coded as
0 = placebo; 1 = prednisone.
survivalnumeric: patient survival time (years).
censinteger: censoring indicator. Coded as 1 = died;
0 = censored.
Andersen PK, Borgan O, Gill RD, Kieding N. Statistical Models Based on Counting Processes. New York: Springer. 2003.
Henderson R, Diggle PJ, Dobson A. Identification and efficacy of longitudinal markers for survival. Biostatistics 2002; 3: 33-50.
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