Table 3.
The Results of Subgroup/Sensitivity Analysis
| Subgroup | N | n | I2 | SMD | 95% CI | P | Subgroup Difference | |
|---|---|---|---|---|---|---|---|---|
| Percent change of total brain volume per year | ||||||||
| Diagnosis | MCI | 2 | 406 | 52% | -0.27 | -0.56 to 0.02 | 0.07 | I2=0%, P=.47 |
| AD | 2 | 218 | 0% | -0.12 | -0.39 to 0.15 | 0.38 | ||
| Sample size | Total n≥100 | 3 | 603 | 18% | -0.22 | -0.40 to -0.04 | 0.02 | I2=0%, P=.42 |
| Total n<100 | 1 | 21 | na | 0.14 | -0.73 to 1.01 | 0.75 | ||
| Duration of study | >1 y | 1 | 242 | na | -0.13 | -0.39 to 0.12 | 0.30 | I2=0%, P=.53 |
| ≤1 y | 3 | 382 | 22% | -0.25 | -0.49 to -0.00 | 0.05 | ||
| Percent change of hippocampal volume per year | ||||||||
| Diagnosis | MCI | 3 | 706 | 76% | -0.17 | -0.48 to 0.13 | 0.27 | I2=0%, P=.46 |
| AD | 2 | 218 | 9 | -0.01 | -0.33 to 0.32 | 0.97 | ||
| Sample size | Total n≥100 | 4 | 903 | 69% | -0.12 | -0.35 to 0.12 | 0.34 | I2=0%, P=.49 |
| Total n<100 | 1 | 21 | na | -0.43 | -1.31 to 0.44 | 0.33 | ||
| Duration of study | >1 y | 1 | 302 | na | 0.03 | -0.19 to 0.26 | 0.77 | I2=33.9%, P=.22 |
| ≤1 y | 4 | 622 | 63% | -0.20 | -0.48 to 0.09 | 0.18 | ||
Abbreviations: AD, Alzheimer’s disease; CI, confidence interval; MCI, mild cognitive impairment; na, not applicable; SMD, standardized mean difference.