Rabinovici GD, et al. - In this longitudinal study, researchers determined whether amyloid positron emission tomography (PET) is correlated with subsequent changes in the management of patients with mild cognitive impairment (MCI) or dementia of uncertain etiology. In all, they noted an association between the use of amyloid PET and changes in clinical management within 90 days among Medicare beneficiaries with MCI or dementia of uncertain etiology evaluated by dementia specialists.

Methods

• Eligible study participants met published appropriate use criteria stating that cognitive impairment etiology was unknown; Alzheimer disease was a diagnostic consideration, and PET results knowledge was expected to change diagnosis and management.
• The study sample consisted of 16,008 patients, among whom 11,409 completed the study procedures and were included in the final analysis.
• Before PET and again 90 (±30) days after PET, dementia specialists documented participants’ diagnosis and management plans.
• At 343 imaging centers, participants underwent amyloid PET.
• The primary end point was management change between the pre- and post-PET visits, as evaluated by a composite outcome that involved Alzheimer disease drug therapy, other drug therapy, and safety and future planning counseling.
• The study was powered to detect a change in the MCI and dementia groups of ≥ 30%.
• One of two secondary end points was reported: the proportion of changes in diagnosis (from Alzheimer disease to non–Alzheimer disease and vice versa) between pre- and post-PET visits.

Results

• Investigators found that the results of amyloid PET were positive in 3,817 MCI patients (55.3%) and 3,154 dementia patients (70.1%).
• In 4,159 out of 6,905 patients with MCI and 2,859 out of 4,504 patients with dementia, the composite endpoint significantly exceeded the threshold of 30% in each group (P < 0.001, 1-sided).
• Overall, the etiological diagnosis changed from Alzheimer's disease to non-Alzheimer's disease in 25.1% of patients and from non-Alzheimer's disease to Alzheimer's disease in 10.5% of patients.