TABLE 1.
Demographic and clinical data summary of training and validation cohorts.
| Training cohort | Validation cohort 1 | Validation cohort 2 | ||
|---|---|---|---|---|
| Patient characteristics | N = 934 | N = 235 | N = 421 | |
| Diagnosis | MCI; N (%) | 761 (81%) | 153 (65%) | 286 (68%) |
| Mild AD; N (%) | 173 (19%) | 82 (35%) | 135 (32%) | |
| Gender | Female; N (%) | 431 (46%) | 136 (58%) | 189 (45%) |
| Male; N (%) | 503 (54%) | 99 (42%) | 232 (55%) | |
| Race | White; N (%) | 706 (76%) | 213 (91%) | 394 (94%) |
| Non‐White; N (%) | 228 (24%) | 22 (9%) | 27 (6%) | |
| ApoE4 status | E4 homozygous; N (%) | 140 (15%) | 39 (17%) | 83 (20%) |
| E4 heterozygous; N (%) | 458 (49%) | 127 (54%) | 210 (50%) | |
| Non‐E4; N (%) | 336 (36%) | 69 (29%) | 128 (30%) | |
| Education | Mean (SD) | 13.4 (3.6) | 14.0 (3.7) | 16.0 (2.7) |
| Age | Mean (SD) | 72.1 (7.3) | 71.2 (8.8) | 73.4 (7.0) |
| BMI | Mean (SD) | 25.9 (4.3) | 25.7 (3.8) | 26.6 (5.0) |
| MMSE | Mean (SD) | 25.8 (2.5) | 26.0 (2.3) | 26.1 (3.0) |
| CDR‐SB | Mean (SD) | 2.6 (1.2) | 2.9 (1.5) | 2.5 (1.8) |
Note: All the demographic and clinical characteristics are significantly different (p < .05) between the cohorts. The training cohort has a significantly greater proportion of MCI and ApoE4‐positive subjects. The first validation cohort (VC 1) has a greater proportion of males. Subjects in the second validation cohort (VC 2) are older and have higher body mass index (BMI). These differences among early AD patients across different clinical trials and observational cohorts help to provide a more generalizable assessment of the performance of the prediction models between the training and validation cohorts.
Abbreviations: BMI, body mass index; CDR‐SB, sum of boxes of clinical dementia rating scale; MCI, mild cognitive impairment; MMSE, Mini‐Mental State Examination; SD, standard deviation.