Table 5.
Power for QALY Test of Equality for Utility = 0.5 and HR = 1.50
| Difference in Percent of Days With Toxicity |
||||||
|---|---|---|---|---|---|---|
| N Per Group | Equal | 50% More | 75% More | Double | Triple | Quadruple |
| 50 | 51 | 58 | 59 | 62 | 71 | 81 |
| 100 | 80 | 86 | 87 | 89 | 95 | 98 |
| 150 | 93 | 96 | 97 | 98 | 99 | 100 |
| 200 | 98 | 99 | 100 | 100 | 100 | 100 |
| 300 | 100 | 100 | 100 | 100 | 100 | 100 |
| 500 | 100 | 100 | 100 | 100 | 100 | 100 |
| 1000 | 100 | 100 | 100 | 100 | 100 | 100 |
QALY = quality-adjusted life year.
Values in bold indicate at least 80% power.
If the overall survival time hazard rate is 1.5, even a sample of 200 events per group will virtually guarantee a significant QALY test.