Table 4.
Estimate of utility matrix for TP, FP, TN and FN
| U (TP) | = 135,000 (savings of 27,000 per year1 per subject for 5 years) |
| + 199,056 (QALY2 set at 39,811 and summed over 5 years) | |
| –24,000 (cost of therapy3 total over 5 years) | |
| –2,000 (cost of PET). = 308,056 | |
| U (FP) | =–$24,000 (cost of therapy) |
| –2,000 = –26,000 | |
| U (TN) | =–2,000 (cost of PET) |
| U (FN) | =–2,000 (cost of PET) |
1The $27,000 per year savings were estimated from Manuel et al. [39] where a savings of 8 billion was estimated if incidence was reduced by 45% by delaying onset for 5 years. 2QALY difference between non-demented and demented set at 0.348 which was valued at $39,811 CAD (Zhang et al. [44]). 3The cost of therapy can vary from approximately $1,000 CAD for a multi domain health promotion five year program [24, 44] up to approximately $400/month (current cost of brand name drugs for dementia therapy are all under $400/month) hence we have used $4,800/y or $24,000 total for the five years as a reasonable upper limit estimate.