Table 2.

The results of linear mixed effect models of $\mathbf{p}\mathbf{T}\mathbf{a}{\mathbf{u}}_{\mathbf{217}}$. Each model included a per-participant random intercept. For each, Sensitivity analysis 1 included observations from eight additional participants who were either cognitively unimpaired or missing a cognitive diagnosis at first available plasma draw (N = 7) or whose $\mathbf{p}\mathbf{T}\mathbf{a}{\mathbf{u}}_{\mathbf{217}}$ values were highly influential (N = 1), and Sensitivity analysis 2 excluded six single observations on five participants for which measured $\mathbf{p}\mathbf{T}\mathbf{a}{\mathbf{u}}_{\mathbf{217}}$ values fell below the lower limit of detection

$\mathrm{pTa}{\mathrm{u}}_{217}$ as a function of GBTM-DVR
	Primary set			Sensitivity set 1			Sensitivity set 2
Predictors	Estimates	CI	P	Estimates	CI	P	Estimates	CI	P
Intercept	0.00	−0.08–0.08	0.968	0.00	−0.12–0.12	0.972	0.00	−0.08–0.08	0.984
GBTM-DVR	0.83	0.75–0.90	<0.001	0.46	0.35–0.56	<0.001	0.83	0.75–0.90	<0.001
Random effects
σ2	0.12			0.32			0.12
τ00	0.25 Reggieid			0.52 Reggieid			0.25 Reggieid
ICC	0.67			0.62			0.67
N	165 Reggieid			173 Reggieid			165 Reggieid
Observations	515			530			509
Marginal R2/conditional R2	0.648/0.885			0.200/0.695			0.649/0.885
$\mathrm{pTa}{\mathrm{u}}_{217}$ as a function of age, moderated by binary PiB status
Intercept	0.23	0.20–0.27	<0.001	0.27	0.21–0.34	<0.001	0.23	0.20–0.27	<0.001
Amyloid positivity	0.19	0.13–0.24	<0.001	0.16	0.06–0.26	0.002	0.19	0.13–0.24	<0.001
Age (centred), linear	0.00	−0.00–0.00	0.337	0.00	−0.00–0.01	0.267	0.00	−0.00–0.00	0.350
Amyloid positivity × age (centred), linear	0.02	0.02–0.03	<0.001	0.01	0.00–0.03	0.021	0.02	0.02–0.03	<0.001
Random effects
σ2	0.01		0.05				0.01
τ00	0.03 Reggieid		0.09 Reggieid				0.03 Reggieid
ICC	0.81		0.66				0.81
N	165 Reggieid		173 Reggieid				165 Reggieid
Observations	515		530				509
Marginal R2/conditional R2	0.355/0.879		0.093/0.695				0.356/0.878

GBTM-DVR = group-based trajectory modelled distribution volume ratio from amyloid PET; ICC = intraclass correlation; $\mathrm{pTa}{\mathrm{u}}_{217}$ = phosphorylated tau 217.

Bold text denotes statistical significance.