Normalization of CSF pTau measurement by Aβ40 improves its performance as a biomarker of Alzheimer’s disease

Table 1 Characteristics of participants in this study

Aβ PET status	Aβ−	Aβ+	p value
341 participants with CSF Aβ₄₀, Aβ₄₂ and pTau, Aβ PET, and tau PET
Sample size	195 (57%)	146 (43%)
CU/MCI/AD	145/46/4	74/45/27
Age (years)	70.4 (9.4)	74.7 (10.4)	< 0.001
Education (years)	18 (2)	16 (3)	0.07
Female (%)	115 (59%)	78 (53%)	0.44
APOE-ε4 (%)	37 (19%)	83 (57%)	< 0.001
Aβ PET (Centiloids)	4.9 (11.0)	71.2 (59.0)	< 0.001
CSF Aβ₄₂	1421 (817)	653 (377)	< 0.001
CSF Aβ₄₀	18,440 (7680)	17,770 (6150)	0.56
CSF pTau	17.8 (8.2)	27.2 (19.9)	< 0.001
CSF pTau/Aβ₄₀	0.0010 (0.0002)	0.0016 (0.0009)	< 0.001
FTP SUVR (Temporal-metaROI)	1.16 (0.08)	1.28 (0.27)	< 0.001
aHCV (mm³)	7530 (1469)	6990 (1750)	< 0.001
PACC	0.25 (5.06)	−2.33 (11.64)	< 0.001
116 participants with ≥ 2 tau PET scans
Sample size	41 (35%)	75 (65%)
CU/MCI/AD	26/14/1	39/25/11
FTP visits (median (IQR, range), no.)	2.0 (1.0, 2–4)	2.0 (1.0, 2–4)
FTP follow-up (Median (IQR, range), years)	1.8 (1.1, 0.8–3.3)	1.2 (1.0, 0.7–3.1)
139 participants with ≥ 2 aHCV data
Sample size	64 (46%)	75 (54%)
CU/MCI/AD	42/20/2	39/24/12
MRI visits (median (IQR, range), no.)	2.0 (0, 2–4)	2.0 (0.5, 2–4)
MRI follow-up (median (IQR, range), years)	2.0 (1.0, 0.9–3.8)	1.2 (0.9, 0.8–3.2)
202 participants with ≥ 2 PACC measurements
Sample size	99 (49%)	103 (51%)
CU/MCI/AD	60/37/2	49/36/18
PACC visits (median (IQR, range), no.)	2 (0, 2–4)	2 (1, 2–5)
PACC follow-up (median (IQR, range), years)	2.0 (1.0, 0.9–3.0)	1.1 (1.0, 0.7–4.0)

Abbreviations: Aβ amyloid-β, AD Alzheimer’s disease, aHCV adjusted hippocampal volume, CU cognitively unimpaired, FTP ¹⁸F-flortaucipir, IQR interquartile range, MCI mild cognitive impairment, PACC Preclinical Alzheimer Cognitive Composite, pTau phosphorylated tau, SUVR standardized uptake value ratio

ISSN: 1758-9193