Table 3.
Standardized model estimates for the 4 mixed effects models.
| Mayo-PACC | PACC-R | ADCS-PACC1 | Global-z | |
|---|---|---|---|---|
|
| ||||
| Fixed Effects | Estimate (95% CI) | Estimate (95% CI) | Estimate (95% CI) | Estimate (95% CI) |
| Age at visit, centered at 76.67 | −0.436* (−0.505, −0.367) |
−0.409* (−0.477, −0.341) |
−0.412* (−0.481, −0.342) |
−0.433* (−0.506, −0.359) |
| Age at visit^2 | −0.091* (−0.128, −0.054) |
−0.084* (−0.119, −0.049) |
−0.087* (−0.124, −0.051) |
−0.111* (−0.144, −0.077) |
| Sex (referenced to females) | −0.223* (−0.278, −0.168) |
−0.39* (−0.445, −0.336) |
−0.272* (−0.328, −0.216) |
−0.165* (−0.223, −0.107) |
| Education, years | 0.249* (0.194, 0.305) |
0.25* (0.195, 0.305) |
0.259* (0.202, 0.315) |
0.318* (0.26, 0.377) |
| Not visit 1 vs. visit 1 | 0.002 (−0.019, 0.023) |
−0.017* (−0.035, 0) |
−0.026* (−0.045, −0.007) |
−0.031* (−0.045, −0.016) |
| Years since visit 1 | 0.25* (0.171, 0.33) |
0.261* (0.191, 0.331) |
0.361* (0.285, 0.436) |
0.26* (0.195, 0.325) |
| Years since visit 1^2 | −0.188* (−0.258, −0.118) |
−0.208* (−0.267, −0.149) |
−0.24* (−0.306, −0.175) |
−0.177* (−0.23, −0.125) |
| PiB status (referenced to A−) | 0.008 (−0.046, 0.063) |
0.01 (−0.044, 0.064) |
−0.011 (−0.067, 0.044) |
−0.018 (−0.076, 0.039) |
| PiB status x Time from Baseline | −0.132* (−0.18, −0.084) |
−0.134* (−0.179, −0.089) |
−0.154* (−0.201, −0.106) |
−0.133* (−0.176, −0.09) |
|
| ||||
| Random Effects | Mayo-PACC | PACC-R | ADCS-PACC | Global-z |
|
| ||||
| SD of intercept | 0.53 | 0.48 | 0.53 | 0.68 |
| SD of residual | 0.34 | 0.25 | 0.30 | 0.27 |
| SD of slope | 0.07 | 0.06 | 0.07 | 0.08 |
| Correlation intercept & slope | 0.26 | 0.20 | 0.21 | 0.25 |
*
p < .05
1
Approximation of the ADCS-PACC as defined in Table 1.
Note. PiB Status is A− when PiB SUVR is less than 1.48 and is A+ when PiB SUVr greater than or equal to 1.48. ADCS: Alzheimer Disease Cooperative Study; PACC: Preclinical Alzheimer’s Cognitive Composite; practice effects are modelled by a term for not visit 1 (e.g., visits 2+) vs. visit 1, as well as a term for time (years) since visit 1 and a term for time (years) since visit 1 squared; visit 1 is the baseline visit; the two age at visit terms (age at visit, centered and age at visit^2) capture longitudinal change, controlling for all other model terms.