Clinical performance of an antibody-free assay for plasma Aβ42/Aβ40 to detect early alterations of Alzheimer’s disease in individuals with subjective cognitive decline

Table 1 Participant characteristics of the FACEHBI cohort at baseline^a

Characteristic	Aβ-PET(−)^b	Aβ-PET(+)^b	P value
Participants, No. (%)	164 (82)	36 (18)
Age, years	66.0 (60.0-69.5)	70.0 (67.0–73.0)	.0003
Female, No. (%)	110 (67)	16 (44)	.0185
*APOE* ɛ4, No. (%)
0 alleles	131 (80)	17 (47)	.0002
1 allele	29 (18)	18 (50)
2 alleles	4 (2)	1 (3)
Duration of education, years	15.0 (12.0–18.0)	16.0 (10.0–18.0)	.9796
FBB-PET, CL	−3.7 (−7.9–1.7)	34.1 (20.3–57.0)	< .0001
MMSE, score	29 (29–30)	30 (29–30)	.1321
S-FNAME, score	33.5 (22.0–46.0)	24.0 (16.0–33.0)	.0013
SFN-N composite, score	−0.03 (−0.61–0.65)	−0.88 (−1.05 to −0.22)	< .0001
Ventricular volume^c,d, mm³	24959.5 (19776.4–32028.2)	29061.4 (21966.7–38034.6)	.1079
Hippocampal volume^c,d, mm³	3606.1 (3421.0–3820.8)	3581.8 (3284.2–3792.7)	.3611
Plasma Aβ40^e, pg/ml	269.3 (243.9–294.2)	297.0 (267.2–317.6)	.0009
Plasma Aβ42^e, pg/ml	70.2 (63.1–77.3)	63.4 (57.8–72.1)	.0041
Plasma Aβ42/Aβ40, ratio	0.261 (0.244–0.279)	0.215 (0.203–0.236)	< .0001

Abbreviations: APOE apolipoprotein E, CL centiloid, FBB-PET ¹⁸F-Florbetaben-PET, MMSE Mini-Mental State Examination, S-FNAME Spanish version of the Face-Name Associative Memory Exam, SFN-N S-FNAME-Name
P values in bold correspond to statistically significant results
^a Data are median values (interquartile range), except for the variables participants, female and APOE ɛ4 number of alleles which are the number of cases (%). Differences between Aβ-PET(−) and Aβ-PET(+) groups were tested using Mann-Whitney and Chi-square tests, as appropriate
^b Aβ-PET status was defined using the cutoff established at 13.5 CL corresponding to early amyloid deposition [16]
^c N=198, data from two participants were lost due to MRI acquisition problems
^d Data correspond to regional volume corrected by total intracranial volume
^e Full-length intact Aβ1-40 and Aβ1-42 were quantified by ABtest-MS

ISSN: 1758-9193