Table 6.

Harrell C statistic and model performance in prediction of any dementia/AD dementia

Categories of predictors	N	Prediction model	Dementia	AD dementia
			Harrell C
Basic model vs. CSF biomarkers	234	Age, RAVLT (basic)	0.69	0.69
		Age, RAVLT, Aβ42	0.73	0.75
		Age, RAVLT, Aβ42, p-tau	0.75	0.78
		Age, RAVLT, Aβ42/p-tau	0.74	0.78
		Age, RAVLT, Aβ42, t-tau	0.76	0.81
		Age, RAVLT, Aβ42/t-tau	0.76	0.81
		Age, RAVLT, Aβ42, p-tau, t-tau	0.78	0.83
Basic model vs. MTA	171	Age, RAVLT (basic)	0.71	0.72
		Age, RAVLT, MTA	0.71	0.72
Basic model vs. APOE ε4 genotype	133	Age, RAVLT (basic)	0.68	0.68
		Age, RAVLT, APOE	0.72	0.72
Basic model vs. SBP	182	Age, RAVLT (basic)	0.69	0.71
		Age, RAVLT, SBP	0.70	0.71
Basic model vs. BMI	141	Age, RAVLT (basic)	0.72	0.71
		Age, RAVLT, BMI	0.74	0.74
Basic model vs. depressive symptoms	183	Age, RAVLT (basic)	0.69	0.72
		Age, RAVLT, Cornell score	0.70	0.74

Predictive performance of the prediction models was explored using the Harrell C statistic (0.5 indicates no predictive value, whereas 1.0 indicates complete prediction, on a scale from 0 to 1). Comparisons of model performance were conducted between models including the same number of patients: basic model (age, RAVLT delayed recall score) and models expanded with additional predictors. AD Alzheimer’s disease, APOE apolipoprotein E, Aβ42 β-amyloid 1–42, BMI body mass index; CSF cerebrospinal fluid, MTA medial temporal lobe atrophy, visual rating, p-tau tau phosphorylated at threonine 181, RAVLT Rey Auditory Verbal Learning Test (delayed recall), SBP systolic blood pressure, t-tau total tau