Should brain scans for older adults with suspected Alzheimer’s disease be covered by Medicare?
Many medical experts say yes. But late last month, an expert panel convened by the Centers for Medicare and Medicaid Services concluded that data supporting use of the scans was weak.
Specifically, the panel noted there is no solid evidence that these imaging tests have a meaningful impact on patients’ health; studies that might establish this have not yet been done.
This controversy deserves attention because positron emission tomography, known as PET scans, are becoming available across the country, and proposed guidelines for their use have just been published by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging.
Currently, Medicare does not pay for the tests, which cost about $3,000 — an amount that puts them out of reach for many families. The expert panel’s findings will be used by the government later this year to determine whether Medicare should change this policy.
Nearly 400 medical centers already offer this technology or are preparing to do so, according to Eli Lilly, which makes a radioactive agent used in the scans. That agent binds to protein clusters known as amyloid plaques that are a signature characteristic of Alzheimer’s disease, making it possible to see them for the first time in the brains of living patients.
The Medicare panel confronted the question: “How useful is this information, for which patients and under what conditions?” Several experts who testified in late January suggested that the PET imaging tests could help physicians diagnose Alzheimer’s disease or other types of dementia. Currently, diagnosis proceeds from a comprehensive medical evaluation, a careful patient history, and typically, a round of neuropsychiatric tests.
“Should I tell my patients that we have a test available to help clarify their diagnosis but we can’t use it because Medicare doesn’t cover it?” asked Dr. Stephen Salloway, a professor of neurology at the Warren Alpert Medical School at Brown University.
If scans show a lack of amyloid plaques, the “worried well” could be reassured that they don’t have Alzheimer’s and doctors could pursue other lines of medical inquiry, like investigating the potential for thyroid problems, depression or vitamin B12 deficiency, said Dr. Paul Aisen, a professor of neuroscience at the University of California, San Diego, School of Medicine.
If the tests are positive, they could rule out conditions like frontotemporal dementia and motivate patients to start taking medications for Alzheimer’s, enroll in clinical trials and get their financial, legal and household affairs in order, other experts said.
But while amyloid plaques are closely associated with Alzheimer’s, their role has not yet been definitively established. They could be a cause of this condition, a byproduct or serve another function not yet understood. Underscoring this is a notable research finding: about 30 percent of older adults with no symptoms of dementia have been found to have amyloid plaque buildup in their brains.
That means the brain scans cannot ensure the accurate diagnosis of Alzheimer’s. “I see a big potential for overuse and misuse,” warned Dr. Raymond Faught, Jr., a member of the Medicare advisory panel and a professor of neurology at Emory University in Atlanta.
Given that large caveat, the question emerges of which patients would benefit most from getting the tests.
The Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging tried to address that in their recently published “appropriate use” guidelines. The guidelines, which have no binding force, suggest that scans should be considered for patients with Alzheimer’s-type symptoms but “an unclear clinical presentation”; those who develop dementia symptoms before age 65; and those with “persistent” mild cognitive impairment, a condition that often precedes Alzheimer’s.
Tests should not be given to “normal” patients or those who have Alzheimer’s disease already, they say. In other words, if you’re getting older, have mild memory loss, but are still functioning well, you’re not a candidate. Nor is there any value in giving the tests to people who are already deep in the throes of dementia.
The recommendations assume that there is value in knowing test results for physicians, patients and families; that physicians will be better able to manage patients’ care as a consequence; and that doctors will order fewer diagnostic tests or more appropriate tests once they have findings from amyloid PET imaging in hand.
But those assumptions are not backed up by solid evidence yet. Medications for patients with Alzheimer’s have a modest impact on symptoms for a limited period of time and no impact on the underlying illness. Given this, “the clinical utility of a diagnostic test to alter patient management and result in a quantifiable benefit is very difficult to establish,” the panel writes in the journal Alzheimer’s & Dementia. Also, they note, “data supporting specific outcomes for amyloid PET are not yet available.”
This lack of data was the reason the Medicare panel gave amyloid brain imaging such low marks late last month. Dr. Rita Redberg, chairwoman of the Medicare Evidence Development and Coverage Advisory Committee and a professor of medicine at the University of California, San Francisco, summed up that group’s deliberations this way:
We were there to evaluate the impact of this test on patient outcomes. But all of the speakers said there wasn’t any data linking amyloid scans to outcomes . . . They presented evidence that the test is very good at identifying amyloid, but they did not present evidence that it was very good at identifying the clinical presence of Alzheimer’s disease.
Wei-Li Shao, senior director of the Alzheimer’s business division of Eli Lilly, which stands to benefit from the greater use of the scans, disagreed, saying, “Lilly remains steadfast and resolved in its belief that amyloid imaging provides significant clinical value for clinicians and patients.” The company will work with Medicare going forward to try to secure coverage, he said.
For Dr. Redberg, the essential question is this: “Would you want to know you have an increased chance of getting a disease in (the future) when there are no effective treatments available and you might not even get it in the end? Is that of benefit to patients?”
What do you think, readers?
The New Old Age Blog: Debate Over Brain Scans and Alzheimer's
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