Extended Data Fig. 3: Effects of demographic characteristics and comorbidities on plasma p-tau217 performance in primary care.

This figure presents the accuracy and predictive values of plasma p-tau217 (Lumipulse) across various subgroups to assess the impact of demographic characteristics and comorbidities in primary care only (n = 548). Results are shown using a single cutoff (a) and using two cutoffs (c). Note that the AUC is independent of cutoffs (b). Participants who fell between the two cutoffs were classified in the intermediate group (d). Data are presented as the observed percentage, and the error bars as the 95% CI derived from the bootstrap distribution. AD pathology was defined as CSF Aβ42/p-tau181 < 11.94 or positive visual read on amyloid PET if lumbar puncture was not performed. The AD pathology prevalence is depicted for each cohort per subgroup in the figure (b). To assess whether the observed difference in the statistics is significantly different from zero, we performed a bootstrap hypothesis test. The P value (two-sided) was calculated as the proportion of bootstrap resamples (n = 2000) where the absolute null-distributed statistic was greater than or equal to the observed difference. Differences between AUCs were assessed with DeLong statistics. Results were not corrected for multiple comparisons. Significant P values in the order as presented in the plot: 0.022; 0.002; 0.007. Abbreviations: Accuracy; percent correctly classified participants; CI, confidence interval; CKD, chronic kidney disease; NPV, negative predictive value; PPV, positive predictive value.