Table 3.

MMRM Estimates of Composite Change From Baseline, by Study^a

Month	Group	Participants, No.	Estimate (SE)	P Value	Adjusted P Valueb	95% CI	σ Valuec	ρ Valued
ADNI Aβ+ (n = 36)vs Aβ− (n = 59)
6	Aβ−	59	−0.133 (0.310)	.67		−0.740 to 0.473
	Aβ+	36	−0.439 (0.401)	.28		−1.225 to 0.348
	Difference		−0.306 (0.503)	.54	.94	−1.291 to 0.679	2.327
12	Aβ−	58	0.581 (0.315)	.07		−0.037 to 1.199
	Aβ+	34	−0.263 (0.414)	.53		−1.075 to 0.549
	Difference		−0.844 (0.516)	.10	.30	−1.857 to 0.168	2.358
24	Aβ−	53	0.558 (0.325)	.09		−0.080 to 1.196
	Aβ+	34	−0.681 (0.415)	.10		−1.494 to 0.132
	Difference		−1.239 (0.522)	.02	.06	−2.263 to −0.215	2.361
36	Aβ−	52	−0.145 (0.356)	.68		−0.843 to 0.553
	Aβ+	27	−0.497 (0.487)	.31		−1.451 to 0.457
	Difference		−0.352 (0.599)	.56	.94	−1.527 to 0.823	2.578	0.459
Area between curves			−26.4 (13.6)	.05
AIBL Aβ+ (n = 47) vs Aβ− (n = 110)
18	Aβ−	110	0.009 (0.215)	.97		−0.412 to 0.429
	Aβ+	47	−1.000 (0.334)	.003		−1.655 to −0.345
	Difference		−1.009 (0.406)	.01	.02	−1.805 to −0.213	2.213
36	Aβ−	104	−0.134 (0.229)	.56		−0.583 to 0.315
	Aβ+	36	−1.538 (0.381)	<.001		−2.285 to −0.791
	Difference		−1.404 (0.452)	.002	.004	−2.290 to −0.519	2.315	0.520
Area between curves			−30.8 (10.1)	.002

Abbreviations: ADNI, Alzheimer’s Disease Neuroimaging Initiative; AIBL, Australian Imaging, Biomarkers, and Lifestyle Flagship Study of Ageing; MMRM, mixed model of repeated measures;

⁺, positive;

⁻, negative.

^aThe models assume heterogeneous compound symmetric covariance structure, which allows different variance parameters (σ) per visit, and a single correlation parameter (ρ).

^bAdjusted for model-based simultaneous inference.

^cResidual standard deviation estimate at each visit.

^dEstimated correlation between visits.