Using subjective cognitive decline to identify high global amyloid in community-based samples: A cross-cohort study

Alzheimers Dement (Amst). 2019 Sep 25:11:670-678. doi: 10.1016/j.dadm.2019.08.004. eCollection 2019 Dec.


Introduction: We aimed to examine the contribution of subjective cognitive decline (SCD) to reduce the number of β-amyloid (Aβ) positron emission tomography scans required for recruiting Aβ+ clinically normal individuals in clinical trials.

Methods: Three independent cohorts (890 clinically normal: 72 yrs ± 6.7; Female: 43.4%; SCD+: 24%; apolipoprotein E [APOE] ε4+: 28.5%; Aβ+: 32%) were used. SCD was dichotomized from one question. Using logistic regression, we classified Aβ+ using the SCD dichotomy, APOEε4, sex, and age.

Results: SCD increased odds of Aβ+ by 1.58 relative to non-SCD. Female APOEε4 carriers with SCD exhibited higher odds of Aβ+ (OR = 3.34), whereas male carriers with SCD showed a weaker, opposing effect (OR = 0.37). SCD endorsement reduces the number of Aβ positron emission tomography scans to recruit Aβ+ individuals by 13% and by 9% if APOEε4 status is known.

Conclusion: SCD helps to classify those with high Aβ, even beyond the substantial effect of APOE genotype. Collecting SCD is a feasible method for targeting recruitment for those likely on the AD trajectory.

Keywords: APOEε4; Alzheimer's disease; Amyloid; Subjective cognitive decline.