Table 2.
Model inputs and equations
| Equations | Coefficient and predictor |
|---|---|
| AHEAD disease equations | |
| Annual rate of change in MMSE | 5.47−0.43 PM1 −0.0042 PM2 + 0.14 PM3 − 0.079 PrevRate + 0.075 Age + Int |
| NPI change from baseline | (5.74 + 0.03 Weeks − 0.59 NPIbase − 0.0012 Weeks ∗ NPIbase + 0.24 NPIPrev − 1.74 White − 3.82 Black + 2.34 PsyMed + 0.12 MMSEbase − 0.22MMSErecent + Int) ∗ 1.44 |
| Total DAD score | 50.51 + 2.55MMSErecent − 0.21NPIrecent − 0.53 Age + 7.28 Female |
| Total DS score | 9.26 − 0.076 MMSErecent − 0.073 DADrecent + 0.035 Age + 0.72 Female |
| ADL change from baseline | 1.3473 + 0.06186 Weeks – 0.7923 ADLBase + 0.7128 ADLPrev + 0.1227 MMSEBase + 0.08959 Age + 0.8146 PsychMed – 3.0529 Black – 0.4922 MMSE |
| IADL change from baseline | 1.2749 + 0.1734 Weeks – 0.8433 IADLBase + 0.00153 IADLBase × Weeks + 0.8357 IADLPrev – 0.6701 Male + 0.1957 MMSEBase – 0.2783 MMSE – 0.157 ADLBase + 0.176 ADL |
| Mortality | |
|---|---|
| Guo et al. 2014 | Weibull shape: 1.85 |
| Weibull scale: 4.60 + 0.11 BsAge – 0.0009 BsAge2 + 0.33 Female + 0.023 BsMMSE |
| Institutionalization | |
|---|---|
| Guo et al. 2014 | |
| In institutional care by MMSE (%) | |
| Mild (25–30) | 0.0 |
| Mild-moderate (20–24) | 0.0 |
| Moderate (15–19) | 3.2 |
| Moderate-severe (10–14) | 17.1 |
| Severe (0–9) | 39.3 |
| Disease severity | MMSE thresholds [18] | CDR-SB thresholds [19] | ADAS-Cog13 thresholds [20] |
|---|---|---|---|
| CN | 29–30 | 0–0.5 | 0–4 |
| SMC | 28–29 | 0.5–1 | 4–7 |
| EMCI | 26–28 | 1–2.5 | 7–12 |
| LMCI | 25–26 | 2.5–4.5 | 12–15 |
| Mild AD | 23–25 | 4.5–7 | 15–21 |
| Mild-moderate AD | 20–23 | 7–9.5 | 21–28 |
| Moderate AD | 15–20 | 9.5–13 | 28–43 |
| Moderate-severe AD | 10–15 | 13–16 | 43–56 |
| Severe AD | 0–10 | 16–18 | 56–85 |
| Utilities | |||
| Patients [17] | 0.99-0.041 DS | ||
| Caregiver [17] | 0.84-0.0015 NPI 12 | ||
| Societal costs of care (monthly cost in U.S. dollar) | ||||||
|---|---|---|---|---|---|---|
| Gustavsson et al. 2011 |
Community care (home) |
Residential care (institutionalized) |
||||
| Predictors | Mild∗ | Moderate | Severe | Mild | Moderate | Severe |
| Intercept | 4184 | 4497 | 4159 | 9409 | 8591 | 8881 |
| CurDAD | −34 | −40 | −52 | 0 | 0 | 0 |
| CurMMSE | 22 | 26 | 34 | 0 | 0 | 0 |
| CurNPIQ12 | 24 | 29 | 37 | 164 | 164 | 166 |
Abbreviations: AHEAD, Assessment of Health Economics in Alzheimer's Disease II; ADAS-Cog, Alzheimer's Disease Assessment Scale–Cognitive Subscale; DAD, Disability Assessment scale for Dementia; DS, Dependence scale; MMSE, Mini-Mental State Examination; NPI, Neuropsychiatric Inventory; NPIQ, Neuropsychiatric Inventory Questionnaire; ADL, Activities of Daily Living; IADL, Instrumental Activities of Daily Living; CN, cognitively normal; SMC, significant memory concern; EMCI, early mild cognitive impairment; LMCI, late mild cognitive impairment; Cur, current level; Bs, baseline level.
NOTE. PMs represent patients' previous MMSE measurements, partitioned over the scale of MMSE. PrevRate is the patient's last known rate of decline; age represents patient age at baseline; Weeks represents weeks of follow-up in the simulation; Months represents months of follow-up in the simulation; NPIbase is the patient's baseline NPI; NPI is the patient's last NPI. White and Black are dummy variables for race; PsychMed is a dummy variable for patients on psychiatric medications at baseline; MMSEbase represents the patient's MMSE at baseline; and MMSE represents the patient's current MMSE; male and female are dummy variables for gender; Int represents a random intercept parameter.
Mild: MMSE 20–25; moderate: MMSE 10–20; severe: MMSE < 10.