Amyloid PET improves management of dementia, mild impairment

  • Rabinovici GD & al.
  • JAMA
  • 2 Apr 2019

  • International Clinical Digest
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  • Findings on amyloid PET more often than not prompted specialists to alter their management for older adults with mild cognitive impairment (MCI) or dementia of uncertain etiology.

Why this matters

Key results

  • Proportion of patients with positive amyloid PET results:
    • 55.3% of those with MCI.
    • 70.1% of those with dementia.
  • Proportion of patients with change in composite management endpoint:
    • 60.2% of those with MCI (P<.001 vs predefined>
    • 63.5% of those with dementia (P<.001 vs predefined>
  • Proportion of patients with change in etiologic diagnosis:
    • 25.1% from Alzheimer’s disease to non-Alzheimer’s disease.
    • 10.5% from non-Alzheimer’s disease to Alzheimer’s disease.

Expert comment

  • In an editorial, Clifford R. Jack Jr, MD, and Ronald C. Petersen, MD, PhD, write, "Given the evidence provided by the IDEAS study that more specific knowledge provided by biomarkers about etiology of impairment was associated with changes in short-term clinical management, a path forward seems apparent. More detailed etiologic characterization by deeper biomarker-based phenotyping will result in more precise, patient-specific management decision making."

Study design

  • Multicenter longitudinal cohort study among 11,409 Medicare beneficiaries with MCI or dementia of unknown etiology cared for by 946 dementia specialists.
  • Main outcome: change in management between pre- and post-PET visits ~90 days apart (composite including Alzheimer’s disease drug therapy, other drug therapy, counseling about safety and future planning).
  • Funding: Alzheimer’s Association; American College of Radiology; Avid Radiopharmaceuticals Inc; others.


  • Lack of randomization, control group.
  • Patient inclusion based on presumption that results would alter management.
  • Effect on clinical outcomes unknown.
  • Small numbers of minority participants.