Fig. 2

Plasma Aβ42/Aβ40 discriminative ability of Aβ-PET status. A Receiver operating characteristic (ROC) curves for discriminating Aβ-PET status. ROC curves are shown for plasma Aβ42/Aβ40, plasma Aβ42/Aβ40 adjusted with age, sex and APOE ɛ4 number of alleles, and the demographic model including only age, sex and APOE ɛ4 number of alleles. B Probability scores distribution derived from the full logistic regression model (Aβ42/Aβ40, age, sex, APOE ɛ4 number of alleles) to predict Aβ-PET status, between Aβ-PET(−) and Aβ-PET(+) groups. Model probability scores were compared between Aβ-PET(−) and Aβ-PET(+) groups using Mann-Whitney test. *** P < .001. Horizontal line depicts median and whiskers depict interquartile range. C, D Concordance plots for plasma Aβ42/Aβ40 levels (C) or full model probability scores (D) and Aβ-PET CL. Black dots correspond to Aβ-PET(−) individuals; red dots correspond to Aβ-PET(+) individuals. Dashed vertical lines represent the CL cutoff for Aβ-PET positivity. Dashed horizontal lines represent the cutoffs for plasma Aβ42/Aβ40 or the model probability score based on maximum Youden index derived by ROC analyses. Concordant classification is represented by the grey area. Abbreviations: APOE, apolipoprotein E; AUC, area under the curve; CI, confidence interval; CL, centiloid; PL, plasma