About Dataset
Data on recurrences of bladder cancer, used by many people to demonstrate methodology for recurrent event modelling.
| Column | Description | Format |
|---|---|---|
| Bladder Dataset 1 | ||
| id | Patient ID | |
| treatment | Treatment received | Placebo, pyridoxine (vitamin B6), or thiotepa |
| number | Initial number of tumors | 8=8 or more |
| size | Size (cm) of largest initial tumor | |
| recur | Number of recurrences | |
| start | Start time of each interval | |
| stop | End time of each 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 recurrence | |
| rsize | Size of largest tumor at recurrence | |
| enum | Event number (observation number within patient) | |
| Bladder Dataset 0 | ||
| id | Patient ID | |
| rx | Treatment received | 1=placebo, 2=thiotepa |
| number | Initial number of tumors | 8=8 or more |
| size | Size (cm) of largest initial tumor | |
| stop | Recurrence or censoring time | |
| enum | Which recurrence (up to 4) | |
| Bladder Dataset 2 | ||
| id | Patient ID | |
| rx | Treatment received | 1=placebo, 2=thiotepa |
| number | Initial number of tumors | 8=8 or more |
| size | Size (cm) of largest initial tumor | |
| start | Start of interval (0 or previous recurrence time) | |
| stop | Recurrence or censoring time | |
| enum | Which recurrence (up to 4) |
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.
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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.
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.