Effectiveness of Florbetapir PET Imaging in Changing Patient Management

Abstract

Aims: To evaluate the impact of amyloid PET imaging on diagnosis and patient management in a multicenter, randomized, controlled study.

Methods: Physicians identified patients seeking a diagnosis for mild cognitive impairment or dementia, possibly due to Alzheimer disease (AD), and recorded a working diagnosis and a management plan. The patients underwent florbetapir PET scanning and were randomized to either immediate or delayed (1-year) feedback regarding amyloid status. At the 3-month visit, the physician updated the diagnosis and recorded a summary of the actual patient management since the post-scan visit. The study examined the impact of immediate versus delayed feedback on patient diagnosis/management at 3 and 12 months.

Results: A total of 618 subjects were randomized (1:1) to immediate or delayed feedback arms, and 602 subjects completed the 3-month primary endpoint visit. A higher proportion of patients in the immediate feedback arm showed a change in diagnosis compared to the controls (32.6 vs. 6.4%; p = 0.0001). Similarly, a higher proportion of patients receiving immediate feedback had a change in management plan (68 vs. 55.5%; p < 0.002), mainly driven by changes in AD medication. Specifically, acetylcholinesterase inhibitors were prescribed to 67% of the amyloid-positive and 27% of the amyloid-negative subjects in the information group compared with 56 and 43%, respectively, in the control group (p < 0.0001). These between-group differences persisted until the 12-month visit.

Conclusion: Knowledge of the amyloid status affects the diagnosis and alters patient management.

Keywords: Alzheimer disease; Amyloid; Diagnosis; Differential diagnosis; Florbetapir.

Fig. 1

Study design. A18 study design and flow. FU, follow-up.

Fig. 2

Impact of amyloid PET information on prescription of AChE-I. p values from the logistic regression model with generalized estimating equations; p < 0.0001 for overall interaction of amyloid status, study arm, and visit. Change in medication use from baseline to 3 months and from baseline to 1 year was significantly greater for the information group than for the control group as indicated by the following symbols: ** p < 0.0001; * p < 0.001; ^‡p < 0.01; ^†p < 0.05. AChE-I use is shown as a percentage of patients at the following time points: pre scan baseline (actual use), pre scan physician-recorded planned use, post scan 3 months (actual use), and post scan 12 months (actual use). Aβ, amyloid beta; AChE-I, acetylcholinesterase inhibitor.