May 17, 2019
Specialized brain scans can have a big impact on the way doctors manage patients with Alzheimer’s disease, according to a new report. The results of such scans can help to clarify a diagnosis in people having memory problems and often affect decisions affecting medications and counseling.
For the study, researchers at the University of California, San Francisco, and other medical centers reviewed medical records of more than 11,000 men and women receiving Medicare who had memory problems. They were being treated at community clinics across the country. All were given PET scans to detect the buildup in the brain of beta-amyloid plaques, a hallmark of Alzheimer’s disease.
When patients’ doctors were given results of the PET scans, their treatment plans, including the use of drugs and counseling, changed nearly two thirds of the time. The scans also changed the way that doctors diagnosed early memory problems in more than one in three patients, and affected whether they referred patients to clinical trials testing new treatments for Alzheimer’s disease.
“We are impressed by the magnitude of these results, which make it clear that amyloid PET imaging can have a major impact on how we diagnose and care for patients with Alzheimer’s disease and other forms of cognitive decline,” said Dr. Gil Rabinovici the study’s lead author and a distinguished professor of neurology at the UCSF Memory and Aging Center. “This was a uniquely real-world study that looked at the impact of amyloid PET imaging in community clinics and other non-academic settings, and demonstrates for the first time how much impact this technology has in real-world dementia care.” The findings appeared in JAMA, from the American Medical Association.
Currently, Alzheimer’s disease can be diagnosed definitively only after a person dies, through autopsy dies. But the use of PET scans, which detect beta-amyloid buildup in the living brain, offers strong clues about who might actually have Alzheimer’s disease.
Though a cure for Alzheimer’s disease remains elusive, earlier diagnosis allows doctors to prescribe appropriate medications that may ease symptoms. Families can also get counseling to help them gain better awareness of safety and care-planning issues. It also allows people with the disease and their families to plan for the future, including legal and financial issues, and accessing resources and support programs.
Positive PET results can allow patients to enter clinical trials testing new drugs. Negative results that show little buildup on beta-amyloid plaque, on the other hand, can prompt doctors to perform tests to look for other causes of changes in thinking and memory, including sleep or mood disorders like depression or medication side effects.
Despite the potential helpfulness of PET scans, they are expensive and often not covered by insurance, so many patients cannot afford them.
Among study participants whose brain scans revealed the presence of significant beta-amyloid deposits, doctors were twice as likely to prescribe Alzheimer’s drugs. Fewer than 40 percent of the patients were getting medications before the scans were performed, compared with more than 80 percent following the scan results.
Doctors discontinued the use of these drugs in some patients whose scans revealed little beta-amyloid deposition. In addition, for approximately one quarter of study participants, physicians changed non-Alzheimer’s drug prescriptions and counseling recommendations based on PET imaging results.
The researchers also discovered that a third of participants who had previously been referred to Alzheimer’s clinical trials showed no sign of beta-amyloid buildup based on PET imaging, which generally rules out Alzheimer’s disease as the cause of their memory and thinking problems. Based on the imaging results, physicians were able to ensure that nearly all patients referred to Alzheimer’s trials were amyloid-positive, which is critical to these trials’ success.
“Accurate diagnoses are critical to ensure patients are receiving the most appropriate treatments. In particular, Alzheimer’s medications can worsen cognitive decline in people with other brain diseases,” said Dr. Rabinovici. “But perhaps more fundamentally, people who come into the clinic with concerns about memory problems want answers. An early, definitive diagnosis may allow individuals to be part of planning for the next phase of their lives and to make decisions that otherwise would eventually need to be made by others.”
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Gil D. Rabinovici, MD; Constantine Gatsonis, PhD; Charles Apgar, MBA; et al: “Association of Amyloid Positron Emission Tomography With Subsequent Change in Clinical Management Among Medicare Beneficiaries With Mild Cognitive Impairment or Dementia.” JAMA April 2, 2019