Table 3.
Multilevel Model Results Comparing the Three Randomization Groups Over Time for Key Outcomes
| Change from baseline | Effect size | Effect test | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Measure | Group | Time | N a | Mean (SD) | Mean (SD) | Cohen’s d | Number improved from baselineb | Multilevel model effect | F(df1, df2) | p |
| Perceived stress | Active | Baseline | 96 | 23.50 (8.93) | Time | F(2, 401.6) = 1.767 | .172 | |||
| 3 months | 71 | 20.77 (6.93) | 3.21 (7.20) | 0.45 | 48/71 (67.6%) | Group | F(2, 254.1) = 0.849 | .429 | ||
| 6 months | 72 | 20.72 (7.10) | 3.09 (7.36) | 0.42 | 44/72 (61.1%) | Group × Time | F(4, 402.1) = 6.697 | <.001 | ||
| AC | Baseline | 111 | 22.66 (8.21) | |||||||
| 3 months | 83 | 21.24 (7.63) | 1.46 (5.58) | 0.26 | 47/83 (56.6%) | |||||
| 6 months | 80 | 22.14 (8.08) | 0.96 (6.06) | 0.16 | 41/80 (51.3%) | |||||
| WLC | Baseline | 54 | 21.73 (7.71) | |||||||
| 3 months | 43 | 23.86 (6.74) | −2.38 (4.80) | −0.50 | 2/43 (27.9%) | |||||
| 6 months | 46 | 23.50 (7.36) | −1.81 (5.74) | −0.32 | 18/46 (39.1%) | |||||
| Depression | Active | Baseline | 96 | 13.14 (9.98) | Time | F(2, 402.4) = 2.058 | .129 | |||
| 3 months | 71 | 10.45 (9.23) | 2.63 (8.58) | 0.31 | 45/71 (63.4%) | Group | F(2, 254.3) = 0.056 | .946 | ||
| 6 months | 72 | 10.51 (8.16) | 2.37 (7.47) | 0.32 | 46/72 (63.9%) | Group × Time | F(4, 402.9) = 2.660 | .032 | ||
| AC | Baseline | 111 | 12.06 (10.09) | |||||||
| 3 months | 83 | 10.52 (9.18) | 1.18 (7.36) | 0.16 | 44/83(53.0%) | |||||
| 6 months | 81 | 11.65 (10.08) | 0.48 (8.70) | 0.05 | 35/81 (43.2%) | |||||
| WLC | Baseline | 54 | 11.08 (8.25) | |||||||
| 3 months | 43 | 12.07 (8.60) | −0.67 (6.13) | −0.11 | 19/43 (44.2%) | |||||
| 6 months | 46 | 12.93 (9.28) | −1.82 (6.27) | −0.29 | 17/46 (37.0%) | |||||
| Anxiety | Active | Baseline | 96 | 35.07 (11.96) | Time | F(2, 404.6) = 1.111 | .330 | |||
| 3 months | 71 | 32.90 (12.31) | 2.30 (9.50) | 0.24 | 37/71 (52.1%) | Group | F(2, 256.0) = 0.159 | .853 | ||
| 6 months | 72 | 31.22 (9.97) | 3.22 (11.14) | 0.29 | 42/72 (58.3%) | Group × Time | F(4, 405.0) = 2.111 | .079 | ||
| AC | Baseline | 111 | 34.61 (13.13) | |||||||
| 3 months | 83 | 32.96 (11.50) | 1.60 (8.67) | 0.18 | 41/83 (49.4%) | |||||
| 6 months | 81 | 34.07 (11.83) | 1.12 (9.28) | 0.12 | 35/81 (43.2%) | |||||
| WLC | Baseline | 54 | 33.41 (11.61) | |||||||
| 3 months | 43 | 35.00 (12.15) | −0.91 (9.97) | −0.09 | 22/43 (51.2%) | |||||
| 6 months | 46 | 35.41 (12.93) | −1.43 (11.31) | −0.13 | 20/46 (43.5%) | |||||
| Burden total | Active | Baseline | 96 | 37.34 (13.77) | Time | F(2, 392.9) = 0.316 | .729 | |||
| 3 months | 69 | 35.26 (13.03) | 2.29 (8.15) | 0.28 | 47/69 (68.1%) | Group | F(2, 257.5) = 0.261 | .770 | ||
| 6 months | 72 | 35.54 (13.63) | 1.43 (9.27) | 0.15 | 42/72 (58.3%) | Group × Time | F(4, 393.2) = 1.711 | .147 | ||
| AC | Baseline | 111 | 35.78 (14.66) | |||||||
| 3 months | 83 | 36.28 (13.49) | 0.69 (8.66) | 0.08 | 46/83 (55.4%) | |||||
| 6 months | 80 | 35.91 (12.96) | 1.22 (7.71) | 0.16 | 43/80 (53.8%) | |||||
| WLC | Baseline | 54 | 35.94 (15.99) | |||||||
| 3 months | 43 | 37.82 (15.80) | −1.23 (7.54) | −0.16 | 17/43 (39.5%) | |||||
| 6 months | 45 | 37.48 (17.31) | −1.70 (7.11) | −0.24 | 19/45 (42.2%) | |||||
| BPSD reaction | Active | Baseline | 96 | 13.84 (9.78) | Time | F(2, 400.7) = 0.570 | .566 | |||
| 3 months | 70 | 10.36 (7.90) | 3.47 (7.77) | 0.45 | 45/68 (66.2%) | Group | F(2, 242.9) = 1.418 | .244 | ||
| 6 months | 70 | 11.30 (8.26) | 2.88 (8.50) | 0.34 | 38/68 (55.9%) | Group × Time | F(4, 381.1) = 2.697 | .031 | ||
| AC | Baseline | 110 | 12.34 (11.89) | |||||||
| 3 months | 79 | 11.60 (9.01) | 0.85 (7.96) | 0.11 | 35/79 (44.3%) | |||||
| 6 months | 78 | 12.28 (9.82) | 0.22 (8.63) | 0.03 | 34/78 (43.6%) | |||||
| WLC | Baseline | 53 | 13.47 (12.30) | |||||||
| 3 months | 42 | 14.50 (10.33) | −1.74 (9.14) | −0.19 | 13/42 (31.0%) | |||||
| 6 months | 43 | 15.00 (12.96) | −1.28 (11.15) | −0.11 | 16/43 (37.2%) | |||||
| Pearlin caregiver competence | Active | Baseline | 96 | 12.11 (2.12) | Time | F(2, 406.2) = 7.790 | <.001 | |||
| 3 months | 71 | 13.21 (1.46) | −1.39 (1.51) | −0.93 | 54/71 (76.1%) | Group | F(2, 253.4) = 1.806 | .166 | ||
| 6 months | 72 | 13.07 (1.71) | −0.97 (1.88) | −0.52 | 38/72 (52.8%) | Group × Time | F(4, 406.8) = 7.129 | <.001 | ||
| AC | Baseline | 111 | 12.44 (1.94) | |||||||
| 3 months | 83 | 12.49 (1.98) | −0.12 (1.73) | −0.07 | 30/83 (36.1%) | |||||
| 6 months | 81 | 12.62 (2.15) | −0.27 (1.72) | −0.16 | 30/81 (37.0%) | |||||
| WLC | Baseline | 54 | 12.31 (2.14) | |||||||
| 3 months | 43 | 11.98 (2.27) | 0.26 (1.88) | 0.14 | 16/43 (37.2%) | |||||
| 6 months | 46 | 12.52 (2.19) | −0.17 (2.01) | −0.09 | 19/46 (41.3%) | |||||
| Pearlin management of situation | Active | Baseline | 96 | 11.27 (2.12) | Time | F(2, 406.2) = 1.217 | .297 | |||
| 3 months | 71 | 12.03 (2.06) | −0.65 (1.66) | −0.39 | 39/71 (54.9%) | Group | F(2, 253.4) = 0.464 | .629 | ||
| 6 months | 72 | 11.93 (2.21) | −0.54 (2.02) | −0.27 | 37/72 (51.4%) | Group × Time | F(4, 406.7) = 3.963 | .004 | ||
| AC | Baseline | 111 | 11.63 (2.00) | |||||||
| 3 months | 83 | 11.35 (2.39) | 0.27 (2.10) | 0.13 | 32/83 (38.6%) | |||||
| 6 months | 81 | 11.78 (1.94) | −0.04 (1.65) | −0.02 | 28/81 (34.6%) | |||||
| WLC | Baseline | 54 | 11.43 (1.93) | |||||||
| 3 months | 43 | 11.40 (1.56) | −0.26 (1.56) | −0.16 | 19/43 (44.2%) | |||||
| 6 months | 46 | 11.22 (1.59) | 0.17 (1.50) | 0.12 | 17/46 (37.0%) | |||||
Note: BPSD = behavioral and psychological symptoms in dementia; SD = standard deviation; AC = attention control; WLC = waitlist control.
aSome questionnaires with missing or skipped items had missing scores for one to two participants at some time points beyond missing data due to attrition. These additional missing scores were minimal.
bNegative ranks that indicate improvements from baseline are shown for all measures except for the two Pearlin measures for which positive ranks indicate improvement from baseline.