Table 2.
Subgroup Meta-Analysis of Memantine and Falls, Syncope, and Related Events.
| Study Characteristics (P for interaction*) | No of Studies | Treated (n / N) | Placebo (n / N) | Pooled OR (95% CI) | P for Heterogeneity | I2† |
|---|---|---|---|---|---|---|
| Fall | ||||||
| Type of cognitive impairment (P for interaction = 0.728) | ||||||
| AD | 8 | 130 / 1609 | 135 / 1427 | 0.94 (0.72, 1.22) | 0.64 | 0% |
| VD or mixed dementia | 1 | 18 / 277 | 21 / 271 | 0.83 (0.43, 1.59) | - | - |
| PDD or DLB | 0 | - | - | - | - | - |
| MCI | 0 | - | - | - | - | - |
| Severity of cognitive impairment (P for interaction = 0.475) | ||||||
| Mild | 0 | - | - | - | - | - |
| Mild to moderate | 4 | 56 / 1013 | 51 / 841 | 1.08 (0.73, 1.60) | 0.65 | 0% |
| Moderate to severe | 4 | 77 / 670 | 91 / 656 | 0.79 (0.56, 1.12) | 0.55 | 0% |
| Severe | 1 | 15 / 203 | 14 / 201 | 1.07 (0.50, 2.27) | - | - |
| Residential status (P for interaction = 0.868) | ||||||
| Community | 8 | 102 / 1753 | 109 / 1566 | 0.91 (0.69, 1.21) | 0.63 | 0% |
| Nursing home | 1 | 46 / 133 | 47 / 132 | 0.96 (0.58, 1.58) | - | - |
| Length of follow-up‡ (P for interaction = 0.580) | ||||||
| < 6 months | 1 | 2 / 17 | 1 / 17 | 2.13 (0.18, 26.0) | - | - |
| 6 – 11 months | 8 | 146 / 1869 | 155 / 1681 | 0.91 (0.71, 1.17) | 0.68 | 0% |
| 12 – 17 months | 4 | 43 / 865 | 37 / 837 | 1.18 (0.64, 2.15) | 0.20 | 36% |
| ≥ 18 months | 0 | - | - | - | - | - |
| Syncope | ||||||
| Type of cognitive impairment (P for interaction = N/A) | ||||||
| AD | 4 | 8 / 854 | 7 / 841 | 1.04 (0.35, 3.04) | 0.44 | 0% |
| VD or mixed dementia | 0 | - | - | - | - | - |
| PDD or DLB | 0 | - | - | - | - | - |
| MCI | 0 | - | - | - | - | - |
| Severity of cognitive impairment (P for interaction = 0.968) | ||||||
| Mild | 0 | - | - | - | - | - |
| Mild to moderate | 1 | 2 / 201 | 2 / 202 | 1.00 (0.14, 7.19) | - | - |
| Moderate to severe | 3 | 6 / 653 | 5 / 639 | 1.07 (0.21, 5.40) | 0.23 | 27% |
| Severe | 0 | - | - | - | - | - |
| Residential status (P for interaction = 0.251) | ||||||
| Community | 3 | 8 / 721 | 5 / 709 | 1.32 (0.42, 4.16) | 0.49 | 0% |
| Nursing home | 1 | 0 / 133 | 2 / 132 | 0.20 (0.01, 4.11) | - | - |
| Length of follow-up‡ (P for interaction = 0.963) | ||||||
| < 6 months | 0 | - | - | - | - | - |
| 6 – 11 months | 4 | 8 / 854 | 7 / 841 | 1.04 (0.35, 3.04) | 0.44 | 0% |
| 12 – 17 months | 4 | 6 / 865 | 5 / 837 | 1.08 (0.34, 3.38) | 0.75 | 0% |
| ≥ 18 months | 0 | - | - | - | - | - |
| Fracture | ||||||
| Type of cognitive impairment (P for interaction = N/A) | ||||||
| AD | 3 | 2 / 492 | 11 / 484 | 0.21 (0.05, 0.85) | 0.90 | 0% |
| VD or mixed dementia | 0 | - | - | - | - | - |
| PDD or DLB | 0 | - | - | - | - | - |
| MCI | 0 | - | - | - | - | - |
| Severity of cognitive impairment (P for interaction = N/A) | ||||||
| Mild | 0 | - | - | - | - | - |
| Mild to moderate | 0 | - | - | - | - | - |
| Moderate to severe | 3 | 2 / 492 | 11 / 484 | 0.21 (0.05, 0.85) | 0.90 | 0% |
| Severe | 0 | - | - | - | - | - |
| Residential status (P for interaction = 0.726) | ||||||
| Community | 2 | 1 / 359 | 5 / 352 | 0.26 (0.04, 1.65) | 0.76 | 0% |
| Nursing home | 1 | 1 / 133 | 6 / 132 | 0.16 (0.02, 1.34) | - | - |
| Length of follow-up‡ (P for interaction = 0.053) | ||||||
| < 6 months | 1 | 0 / 17 | 2 / 17 | 0.18 (0.01, 3.98) | - | - |
| 6 – 11 months | 2 | 2 / 475 | 9 / 467 | 0.22 (0.05, 1.05) | 0.65 | 0% |
| 12 – 17 months | 1 | 7 / 246 | 3 / 245 | 2.36 (0.60, 9.25) | - | - |
| ≥ 18 months | 0 | - | - | - | - | - |
| Accidental Injury | ||||||
| Type of cognitive impairment (P for interaction = 0.152) | ||||||
| AD | 6 | 58 / 1459 | 58 / 1278 | 0.93 (0.63, 1.37) | 0.54 | 0% |
| VD or mixed dementia | 1 | 17 / 277 | 30 / 271 | 0.53 (0.28, 0.98) | - | - |
| PDD or DLB | 0 | - | - | - | - | - |
| MCI | 0 | - | - | - | - | - |
| Severity of cognitive impairment (P for interaction = 0.784) | ||||||
| Mild | 0 | - | - | - | - | - |
| Mild to moderate | 4 | 54 / 1013 | 57 / 841 | 0.94 (0.52, 1.71) | 0.14 | 46% |
| Moderate to severe | 2 | 11 / 520 | 15 / 507 | 0.70 (0.31, 1.56) | 0.76 | 0% |
| Severe | 1 | 10 / 203 | 16 / 201 | 0.60 (0.27, 1.35) | - | - |
| Residential status (P for interaction = N/A) | ||||||
| Community | 7 | 75 / 1736 | 88 / 1549 | 0.80 (0.56, 1.12) | 0.38 | 6% |
| Nursing home | 0 | - | - | - | - | - |
| Length of follow-up‡ (P for interaction = 0.949) | ||||||
| < 6 months | 0 | - | - | - | - | - |
| 6 – 11 months | 7 | 75 / 1736 | 88 / 1549 | 0.80 (0.56, 1.12) | 0.38 | 6% |
| 12 – 17 months | 4 | 28 / 714 | 34 / 672 | 0.78 (0.46, 1.30) | 0.81 | 0% |
| ≥ 18 months | 0 | - | - | - | - | - |
Abbreviations: AD, Alzheimer's disease; CI, confidence interval; DLB, dementia with Lewy body; MCI, mild cognitive impairment; N/A, non-applicable; OR, odds ratio; PDD, Parkinson disease with dementia; VD, vascular dementia.
*
P value for interaction was computed from the meta-regression model that investigated the variations in effect size by a study-level characteristic.
†
I2 measures the proportion of heterogeneity in individual studies that cannot be explained by chance.
‡
Open-label extension studies of placebo-controlled trials were included so that the number of studies may be greater.