Abstract Details

Evaluate the role of amyloid-beta PET scans as a diagnostic tool in clinical settings and its influence on patient care management with respect to Alzheimer’s disease drug therapy.

The NIA-AA 2018 guidelines for clinical research define Alzheimer’s disease (AD) on a biological basis, requiring the presence of amyloid deposition in the brain. This framework helps to more precisely define the processes underlying cognitive impairment, and is particularly poignant given the advent of amyloid-beta PET scans which allow the visualization of amyloid-beta in vivo. It is unclear how this framework may lead to changes in management of patients, particularly in an ethnically and culturally diverse location such as in South Florida.

We included 102 cognitively impaired patients from the multi-site Khatib Study (mean age 77+/-7 years, 45% women, 15% Hispanic). Patients were evaluated for AD drug therapy (cholinesterase inhibitors and memantine) before and after amyloid-beta PET scan by neurologists. The probabilities of change in AD drug therapy by amyloid-beta PET scan results were estimated using Wilson intervals for binomial proportions and tested using the McNemar test.

For amyloid PET positive patients (n=68), the use of AD drug therapy increased significantly (p<.05), from 78% (95%CI [67,86]) to 91% (95% CI [82,96]). A total of 15% (95%CI [8,25]) started AD drug therapy and 2% (95%CI [0.3,8]) stopped AD drug therapy. For amyloid PET negative patients (n=34), the use of AD drug therapy decreased significantly (p<.05), from 76% (95%CI [60,88]) to 53% (95%CI [37,69]). A total of 29% (95%CI [17,46]) stopped AD drug therapy and 6% (95%CI [2,19]) started AD drug therapy.

Clinical confirmation of patients’ amyloid PET status resulted in increases in prescribed AD drug therapy for amyloid positive patients and decreases in the amyloid negative patients. This study highlights the significant bidirectional influence of amyloid PET scans on patient care management.