Imaging Dementia — Evidence for Amyloid Scanning (IDEAS) Study: A Coverage with Evidence Development Longitudinal Cohort Study
Sponsored by: Alzheimer’s Association
Managed by: American College of Radiology, American College of Radiology Imaging Network®
Advisor: Centers for Medicare & Medicaid Services (CMS)
Gil D. Rabinovici, MD
University of California, San Francisco
Bruce E. Hillner, MD
Virginia Commonwealth University
Rachel A. Whitmer, PhD
Division of Research
Barry A. Siegel, MD
Maria C. Carrillo, PhD
Constantine Gatsonis, PhD
Center for Statistical Sciences
|IDEAS Study Operations Office
American College of Radiology
1818 Market Street, Suite 1720 Philadelphia, PA 10103
|Clinicaltrials.gov ID: NCT02420756|
STUDY OBJECTIVES/SPECIFIC AIMS
The Imaging Dementia — Evidence for Amyloid Scanning (IDEAS) Study will establish an open-label, longitudinal cohort study to assess the impact of amyloid PET on patient outcomes under Coverage with Evidence (CED) in patients meeting appropriate use criteria (AUC) for amyloid PET (Johnson et al. 2013). Our hypothesis is that amyloid PET will decrease uncertainty and increase confidence in the underlying cause of cognitive impairment, that this will translate into earlier counseling and interventions in these domains, and that these interventions will lead to improved outcomes.
Aim 1: To assess the impact of amyloid PET on the management of patients meeting Appropriate Use Criteria (AUC). [Clinical Data to address Aim 1 will be collected for the first 11,050 participants in this study.]
Aim 2: To assess the impact of amyloid PET on hospital admissions and emergency room visits in patients enrolled in the study cohort (amyloid PET-known) compared to matched patients not in the cohort (amyloid PET-naïve) over 12 months. [CMS Claims Data to address Aim 2 will be collected from all participants registered to the longitudinal study cohort and from concurrent controls matched according to a validated algorithm.]
Participants must be Medicare beneficiaries referred by qualified dementia specialists who meet AUC for amyloid PET (Johnson et al. 2013). Specifically, patients must meet the following criteria:
- Cognitive complaint verified by objectively confirmed cognitive impairment
- Etiologic cause of cognitive impairment is uncertain after a comprehensive evaluation by a dementia expert, including general medical and neurological examination, mental status testing including standard measures of cognitive impairment (e.g., Mini Mental State Examination [MMSE] or Montreal Cognitive Assessment), laboratory testing for toxic-metabolic disturbances and structural neuroimaging (CT or MRI)
- Alzheimer’s disease (AD) is a diagnostic consideration
- Knowledge of amyloid PET status is expected to alter diagnosis and management
Patients will be recruited into one of two sub-cohorts:
- Progressive, unexplained mild cognitive impairment (MCI); and
- Dementia of uncertain etiology.
Aim 1. The projected prospectively-recruited sample size of amyloid PET-known participants for Aim 1 is 11,050 participants (assuming a distribution of 40% dementia and 60% MCI).
Aim 2. The projected prospectively-recruited sample size of amyloid PET-known participants for Aim 2 is 18,488 participants.
Amyloid PET imaging represents a potential major advance in the clinical assessment of cognitively impaired patients, enabling for the first time in vivo detection of neuritic plaques, a core element of AD neuropathology. The U.S. Food and Drug Administration (FDA) has approved three amyloid PET imaging radiopharmaceuticals for clinical use based on evidence that visual interpretations of PET scans performed during life were sensitive and specific for the presence of moderate to frequent neuritic plaques at autopsy: F-18 florbetapir (Amyvid™), F-18 flutametamol (Vizamyl™), and F-18 florbetaben (Neuraceq™). Though amyloid PET has undoubtedly made a considerable contribution to AD research, data supporting its clinical utility are relatively sparse. Since amyloid scans can be positive in cognitively normal individuals and those with cognitive impairment due to causes other than AD, imaging results must be considered in the context of a full evaluation for cognitive impairment to avoid misdiagnosis.
To help allay concerns about potentially misleading clinical use of amyloid PET, a working group under the auspices of the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging developed appropriate use criteria (AUC) to guide clinicians (Johnson et al. 2013). The AUC indicate that amyloid PET should only be considered in patients with objective cognitive deficits when there is substantial diagnostic uncertainty after a comprehensive evaluation by a dementia specialist and in whom scan results are expected to increase diagnostic certainty and alter patient management. Per AUC, amyloid PET may have greatest value in patients with either: (1) progressive, unexplained MCI; or (2) dementia of uncertain etiology (due to atypical or mixed clinical features, or unusually early age-of-onset). Although the AUC are based upon available evidence and expert opinion, there is no experience with their implementation in clinical practice.
To direct a recommendation on the use of amyloid PET, IDEAS will enroll a total of 18,488 Medicare beneficiaries meeting AUC over 24 months at sites throughout the United States. Dementia specialists will team with PET facilities that have access to perform amyloid PET and with trained radiologists and nuclear medicine physicians, all of whom will consent to completing the data requirements and timelines for the study. Amyloid PET will be performed and interpreted at each facility with results provided to the ordering physician for support in further decision making, which will be captured for the study. Assessments for the study will include evaluation of the impact of amyloid PET on short-term patient management by comparing pre-PET intended management (documented in a case report form [CRF] prior to amyloid PET imaging) to post-PET actual management (CRF completed within ~90 days after PET) and evaluation of the impact of amyloid PET on hospital admissions and emergency room visits in patients enrolled in the cohort (amyloid PET-known) compared to matched patients not in the cohort (amyloid PET-naïve) over 12 months.
Johnson KA, Minoshima S, Bohnen NI, et al. (2013) “Update on Appropriate Use Criteria for Amyloid PET Imaging: Dementia Experts, Mild Cognitive Impairment, and Education.” J Nuc Med 54(7):1011-1013. doi: 10.2967/jnumed.113.127068. Epub 2013 Jun 10.