A randomized controlled trial of amyloid positron emission tomography results disclosure in mild cognitive impairment

Abstract

Introduction: Recent studies suggest that Alzheimer's disease (AD) biomarker disclosure has no discernable psychological impact on cognitively healthy persons. Far less is known about how such results affect symptomatic individuals and their caregivers.

Methods: Randomized controlled trial of 82 mild cognitive impairment (MCI) patient and caregiver dyads (total n = 164) to determine the effect of receiving amyloid positron emission tomography results on understanding of, and perceived efficacy to cope with, MCI over 52 weeks of follow-up.

Results: Gains in the primary outcomes were not consistently observed. Amyloid negative patients reported greater perceived ambiguity regarding MCI at follow-up, while moderate and sustained emotional distress was observed in patients, and to a lesser extent, caregivers, of those who were amyloid positive. There was no corresponding increase in depressive symptoms.

Discussion: These findings point to the possibility that both MCI patients and caregivers may need emotional support after the disclosure of amyloid scan results.

Keywords: amyloid positron emission tomography; biomarker disclosure; caregiving; ethics; mild cognitive impairment.

Conflict of interest statement

Conflict of Interest Statement: Florbetapir F 18 Injection doses in this study are supplied at no cost by Avid Radiopharmaceuticals a wholly owned subsidiary of Eli Lily, Inc. Dr. Lopez provides consultation to Grifols, Inc.

© 2020 the Alzheimer's Association.

Figures

Figure 1.

Consort diagram. ADRC, Alzheimer Disease Research Center (University of Pittsburgh); PT, patient; CG,caregiver *N=12 patients had previously undergone a research PET amyloid scan under a protocol that precluded results disclosure. The randomization process was overridden in these cases and participants were assigned to the scan group, with the opportunity to undergo a new amyloid PET scan and results disclosure. This deviation did not impact the balance of the study groups (including the subgroups of amyloid positive and negative cases) on key baseline characteristics or primary outcomes measures.

Figure 2.

Psychological safety. Measures of mood over time CESD, Center for Epidemiological Studies Depression Scale; STAI, Speilberger State Anxiety Inventory; Aβ, amyloid beta.

Figure 3.

Post-disclosure impact of event scores over time. IES, Impact of Events Scale; IGT, Impact of Genetic Testing Scale; Aβ, amyloid beta An IES total score cut-off point of 26 is noted by a dashed line above which a moderate or severe impact may be indicated