Preliminary results of the Imaging Dementia – Evidence for Amyloid Scanning (IDEAS) trial are in, and they’re better than anticipated, says Barry Siegel, MD, professor of radiology at MIR and a member of the study’s steering committee. “We met our first target.”
Barry Siegel, MD
The “we” Siegel refers to is the IDEAS study leadership, a small group of senior scientists and professors. And the “first target,” or Aim 1 of the national trial, was to determine the impact of brain amyloid PET scans on managing patients 65+ years, who have experienced cognitive decline of an unknown cause, and met the appropriate use criteria for clinical amyloid PET.
Amyloid plaque builds up in the brains of patients with Alzheimer’s and is a core characteristic of the disease. Before brain amyloid PET scans, amyloid plaque could only be detected in autopsies, making a diagnosis of the disease in living patients difficult.
The IDEAS study is a response to the 2013 Centers for Medicare & Medicaid Services (CMS) decision not to cover the amyloid PET scans in persons with suspected dementia or neurodegenerative disease. Although CMS concluded at the time that there was insufficient evidence of the imaging exam’s value in making diagnoses and treating these conditions, it is paying for one scan per participant in the study.
Participants are Medicare beneficiaries from throughout the U.S. and will number 18,500. MIR is one of 378 PET imaging facilities and has scanned 204 patients so far.
Aim 1: Exceeding Expectations
“Results exceeded our expectations by almost a factor of two,” says Siegel. Changes in medical management occurred in 67.8% of patients with progressive but mild cognitive decline, and 65.9% in patients with atypical dementia. Researchers originally hypothesized a 30% change in medical management.
Results are interim and reflect approximately 4000 of the 11,000 patients enrolled in this portion of the study. Dementia specialists participating in the study completed assessment forms before their patients underwent the PET scan and 90 days after the exam. The forms were analyzed by statisticians to identify and document changes in patient management. They wanted to see if there was a change in medication and/or in counseling.
Aim 2: Expect a Wait
“The harder part will happen when we sit down and do the much more complicated analyses of Aim 2,” says Siegel. It will involve comparing Medicare claims of patients enrolled in the study against a cohort of matched patients, who did not have the amyloid PET scan and were not involved in the study. The goal is to determine the impact of the scans on major outcomes. Medicare is really interested in outcomes, Siegel says. They want to see if hospitalizations and emergency department visits decreased in those patients whose medical management changed. “That’s going to be a tough one. We’re not positive one way or another whether or not we’re going to be able to prove that,” Siegel says. “We’ll see what happens but it’s going to take a while, probably two years before we have the answer.”