Table.
Participant Characteristics By Brain Amyloid Groupa
| Normal Brain Amyloid (n = 243) |
Elevated Brain Amyloid (n = 202)b |
Overall (N = 445) |
P Valuec | |
|---|---|---|---|---|
| Baseline Characteristics | ||||
| Age, mean (SD), y | 73.4 (5.8) | 74.7 (6.0) | 74.0 (5.9) | .02 |
| Women | 115 (47) | 118 (58) | 233 (52) | .02 |
| Education, mean (SD), y | 16.7 (2.7) | 16.1 (2.6) | 16.4 (2.7) | .02 |
| Family history of dementia | 88 (36) | 87 (43) | 175 (39) | .14 |
| Ethnicity | ||||
| Not Hispanic/Latino | 233 (96) | 193 (96) | 426 (96) | .75 |
| Hispanic/Latino | 9 (4) | 7 (3) | 16 (4) | |
| Unknown | 1 (0.4) | 2 (1) | 3 (1) | |
| Race | ||||
| American Indian/Alaskan native | 0 | 1 (0.5) | 1 (0.2) | .39 |
| Asian | 4 (2) | 2 (1) | 6 (1) | |
| Black | 15 (6) | 14 (7) | 29 (7) | |
| White | 223 (92) | 181 (90) | 404 (91) | |
| More than 1 race | 1 (0.4) | 4 (2) | 5 (1) | |
| Subjective memory concern | 54 (22) | 50 (25) | 104 (23) | .53 |
| ≥1 APOEz4 allele | 40 (16) | 85 (42) | 125 (28) | <.001 |
| PACC (z score composite), mean (SD)d | 0.32 (2.53) | −0.38 (2.64) | 0.00 (2.60) | .02 |
| MMSE, mean (SD)d | 29.1 (1.2) | 29.0 (1.1) | 29.0 (1.2) | .99 |
| Logical Memory Delayed Recall, mean (SD)d | 13.4 (3.2) | 12.9 (3.3) | 13.1 (3.3) | .08 |
| ADAS13, mean (SD)d | 9.0 (4.3) | 9.5 (4.4) | 9.2 (4.3) | .28 |
| CDR-Sum of Boxesd | ||||
| 0 | 227 (93) | 186 (92) | 413 (93) | .51 |
| 0.5 | 16 (7) | 15 (7) | 31 (7) | |
| 1 | 0 | 1 (0.5) | 1 (0.2) | |
| Ventricular volume, mean (SD), % ICV | 2.1 (1.1) | 2.3 (1.1) | 2.2 (1.1) | .07 |
| CSF tau, mean (SD), pg/mLe | 59.4 (22.5) | 76.8 (38.4) | 67.8 (32.3) | <.001 |
| CSF pTau, mean (SD), pg/mLe | 26.5 (11.8) | 38.1 (22.3) | 32.1 (18.6) | <.001 |
| CSF Aβ42 <192 pg/mLe | 0/194 | 155/178 (87) | 155/372 (42) | |
| CSF Aβ42, mean (SD), pg/mLe | 238.9 (26.6) | 157.5 (36.8) | 200.0 (51.7) | |
| Amyloid PETSUVR, >1.1e,f | 0/208 | 138/177 (78) | 138/385 (36) | |
| Amyloid PET SUVR, mean (SD)e,f | 1.0 (0.06) | 1.2 (0.19) | 1.11 (0.18) | |
| Elevated brain amyloid by PET and CSFe | 0/159 | 91/153 (59) | 91/312 (29) | |
| Follow-up Characteristics | ||||
| Follow-up, mean (SD), y | 4.2 (2.8) | 3.7 (2.6) | 3.9 (2.7) | .05 |
| Last known status | ||||
| Active | 158 (65) | 121 (60) | 279 (63) | .34 |
| Lost to follow-up | 82 (34) | 80 (40) | 162 (36) | |
| Death | 3 (1) | 1 (0.5) | 4 (1) | |
| Progression to dementia | 7 (3) | 13 (6) | 20 (4) | .01 |
| Initiated antidementia medicationg | 9 (4) | 20 (10) | 29 (7) | .01 |
Abbreviations: Aβ42, β-amyloid; ADAS13, Alzheimer Disease Assessment Scale 13-item cognitive subscale; APOEε4, apolipoprotein E; CDR, Clinical Dementia Rating; CSF, cerebrospinal fluid; ICV, intracranial volume; MMSE, Mini-Mental State Examination; PACC, Preclinical Alzheimer Cognitive Composite; pTau, phospho-tau; PiB, Pittsburgh Compound B; PET, positron emission tomography; SUVR, standard uptake value ratio.
Data are reported as No. (%) unless otherwise indicated.
Elevated brain amyloid was defined as baseline amyloid PET SUVR>1.1 or CSF Aβ<192 pg/mL. Amyloid PET refers to florbetapir or transformed PiB PET.
Based on 2-sample t tests, Pearson χ2 tests, or log-rank tests (for progression to dementia, see eFigure 14 in the Supplement).
Score explanations: PACC, a sum of 4 baseline standardized z scores (decreases with worse performance); MMSE range, 0 (worst) to 30 (best); Logical Memory Delayed Recall range, 0 (worst) to 25 (best) story units; ADAS13 range, 0 (best) to 85 (worst); and CDR-Sum of Boxes range, 0 (best) to 18 (worst).
Data were based on 445 participants unless otherwise stated. For CSF tau, 369; for CSF pTau, 371; for CSF Aβ42 <192 pg/mL and also for CSF Aβ42, mean (SD), pg/mL, 372; for amyloid PET (SUVR) >1.1 and also for amyloid PET (SUVR), mean (SD), 385; and for elevated brain amyloid by PET and CSF, 312 participants.
Some missing baseline amyloid PET SUVRs were linearly interpolated from follow-up florbetapir PET SUVRs (n = 55 normal and n = 36 elevated) or PiB PET SUVRs (n = 7 normal and n = 12 elevated).
Antidementia medications included donepezil, tacrine, rivastigmine, memantine, or galantamine.