Epilepsy Data

Description

A randomised clinical trial investigating the effect of an anti-epileptic drug.

Usage

data("epilepsy")

Format

A data frame with 236 observations on the following 6 variables.

treatment

the treatment group, a factor with levels placebo and Progabide.

base

the number of seizures before the trial.

age

the age of the patient.

seizure.rate

the number of seizures (response variable).

period

treatment period, an ordered factor with levels 1 to 4.

subject

the patient ID, a factor with levels 1 to 59.

Details

In this clinical trial, 59 patients suffering from epilepsy were randomized to groups receiving either the anti-epileptic drug Progabide or a placebo in addition to standard chemotherapy. The numbers of seizures suffered in each of four, two-week periods were recorded for each patient along with a baseline seizure count for the 8 weeks prior to being randomized to treatment and age. The main question of interest is whether taking progabide reduced the number of epileptic seizures compared with placebo.

Source

P. F. Thall and S. C. Vail (1990), Some covariance models for longitudinal count data with overdispersion. Biometrics, 46, 657–671.

Examples

  data("epilepsy", package = "HSAUR")
  library(lattice)
  dotplot(I(seizure.rate / base) ~ period | subject, data = epilepsy, 
          subset = treatment == "Progabide")
  dotplot(I(seizure.rate / base) ~ period | subject, data = epilepsy, 
          subset = treatment == "Progabide")