Table 3:
Mediation analysis with causal effects estimated for presence of dementia at the mean level of the covariates, based on accelerated failure time models (AFT).
| NDE b (95% CI) | NIE c (95% CI) | |
|---|---|---|
| Pre-existing dementia | 0.63 (0.55, 0.72) | 0.91 (0.88, 0.94) |
| Co-existing dementia | 0.76 (0.67, 0.85) | 0.93 (0.91, 0.95) |
NDE (natural direct effect): estimated effect on the mean survival time of a person simply having dementia but treated just like a person without dementia, compared to a person without dementia. It captures decrease in survival due to having dementia.
NIE (natural indirect effect): estimated impact on effect on the mean survival time of current chemotherapy practice for people with dementia, compared to the hypothetical situation where a person with dementia is as likely to get chemotherapy as a person without dementia. It captures the decrease in survival time due to someone with dementia potentially receiving more aggressive treatment.