bladder | R Documentation |

Data on recurrences of bladder cancer, used by many people to demonstrate methodology for recurrent event modelling.

Bladder1 is the full data set from the study. It contains all three treatment arms and all recurrences for 118 subjects; the maximum observed number of recurrences is 9.

Bladder is the data set that appears most commonly in the literature. It uses only the 85 subjects with nonzero follow-up who were assigned to either thiotepa or placebo, and only the first four recurrences for any patient. The status variable is 1 for recurrence and 0 for everything else (including death for any reason). The data set is laid out in the competing risks format of the paper by Wei, Lin, and Weissfeld.

Bladder2 uses the same subset of subjects as bladder, but formatted in the (start, stop] or Anderson-Gill style. Note that in transforming from the WLW to the AG style data set there is a quite common programming mistake that leads to extra follow-up time for 12 subjects: all those with follow-up beyond their 4th recurrence. This "follow-up" is a side effect of throwing away all events after the fourth while retaining the last follow-up time variable from the original data. The bladder2 data set found here does not make this mistake, but some analyses in the literature have done so; it results in the addition of a small amount of immortal time bias and shrinks the fitted coefficients towards zero.

```
bladder1
bladder
bladder2
data(cancer, package="survival")
```

bladder1

id: | Patient id |

treatment: | Placebo, pyridoxine (vitamin B6), or thiotepa |

number: | Initial number of tumours (8=8 or more) |

size: | Size (cm) of largest initial tumour |

recur: | Number of recurrences |

start,stop: | The start and end time of each time interval |

status: | End of interval code, 0=censored, 1=recurrence, |

2=death from bladder disease, 3=death other/unknown cause | |

rtumor: | Number of tumors found at the time of a recurrence |

rsize: | Size of largest tumor at a recurrence |

enum: | Event number (observation number within patient) |

bladder

id: | Patient id |

rx: | Treatment 1=placebo 2=thiotepa |

number: | Initial number of tumours (8=8 or more) |

size: | size (cm) of largest initial tumour |

stop: | recurrence or censoring time |

enum: | which recurrence (up to 4) |

bladder2

id: | Patient id |

rx: | Treatment 1=placebo 2=thiotepa |

number: | Initial number of tumours (8=8 or more) |

size: | size (cm) of largest initial tumour |

start: | start of interval (0 or previous recurrence time) |

stop: | recurrence or censoring time |

enum: | which recurrence (up to 4) |

Andrews DF, Hertzberg AM (1985), DATA: A Collection of Problems from Many Fields for the Student and Research Worker, New York: Springer-Verlag.

LJ Wei, DY Lin, L Weissfeld (1989),
Regression analysis of multivariate incomplete failure time data by
modeling marginal distributions.
*Journal of the American Statistical Association*,
**84**.

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