Table 1.
Example Scenarios for the Effects of a Decision Aid on Outcome
| Number of Women | Predicted Survival without Adjuvant Therapy, % | Predicted Survival with Adjuvant Therapy, % | Proportion Choosing Adjuvant Therapy in Decision Aid Group | Proportion Choosing Adjuvant Therapy in the Control Group | Predicted Deaths in Adjuvant! Group, n | Predicted Deaths in Control Group, n |
|---|---|---|---|---|---|---|
| Scenario 1 | ||||||
| 350 | 79 | 80 | 55% | 85% | 71.6 | 70.5 |
| 350 | 70 | 75 | 88% | 88% | 89.6 | 89.6 |
| 150 | 60 | 70 | 92% | 92% | 46.2 | 46.2 |
| 150 | 30 | 45 | 95% | 95% | 83.6 | 83.6 |
| 1000 | 781 | 886 | 291 | 290 | ||
| Scenario 2 | ||||||
| 350 | 79 | 80 | 55% | 85% | 71.6 | 70.5 |
| 350 | 70 | 75 | 92% | 88% | 88.9 | 89.6 |
| 150 | 60 | 70 | 96% | 92% | 45.6 | 46.2 |
| 150 | 30 | 45 | 98% | 95% | 83 | 83.6 |
| 1000 | 806 | 886 | 289 | 290 | ||
In the first scenario, the only effect of the decision aid is that some women with little to gain from adjuvant therapy forgo treatment. This leads to an additional 1 death per 1000 patients. In scenario 2, the decision aid also increases the proportion of high-risk women choosing treatment, leading to a decrease in the death rate. The number of deaths is calculated using the following formula: number of women ×proportion choosing adjuvant therapy ×(1 − survival with adjuvant therapy) +number of women ×(1 − proportion choosing adjuvant therapy) ×(1 − survival without adjuvant therapy).