OF LIZETTE BORRELI
Physicians have frequently changed the clinical management of Medicare beneficiaries with mild cognitive impairment (MCI) and dementia of uncertain etiology as a result of amyloid PET scans, according to the published Dementia-Dementia Imaging Dementia (IDEAS) study online on April 2nd in Journal of the American Medical Association (JAMA).
The study, the first phase of a four-year effort to provide evidence on the clinical utility of amyloid PET scans, was largely aimed at addressing the concerns of the Medicare and Medicaid Service Centers, which they had previously concluded that there was insufficient evidence to justify routine coverage for amyloid PET scans, which can cost $ 4000 to $ 5000. CMS had agreed to consider coverage if the studies could provide evidence that amyloid PET improves health outcomes, including changes in management and long-term outcomes of dementia.
Among the findings, IDEA investigators reported that amyloid scans led to changes in Alzheimer's diagnosis to non-Alzheimer's (AD) in 25.1% of cases and altered clinical management in about two thirds of all patients, after 90 days.
"As reported in previous studies, the use of amyloid PET was associated with frequent changes in diagnosis, improved diagnostic safety and reduced use of other diagnostic tests," the researchers, led by Gil Rabinovici, MD, of University of California, San Francisco, wrote.
To assess whether amyloid PET has an added value in routine clinical practice, the team analyzed data from 16,008 Medicare beneficiaries aged 65 and over, enrolled in the IDEAS study from February 2016 to September 2017. Approximately 71.3 % 16,008 registered participants (with an average age of 75) completed the study. Participants either had a diagnosis of MCI or dementia established by a dementia specialist in the last 24 months.
A total of 946 dementia specialists from 595 unique practices in the United States participated in the study. The specialists documented the diagnosis and the management plan of the participants before the PET scans and then again 90 days after the PET.
The PET results of amyloid were positive in 3817 patients with MCI (55.3%) and 3154 patients with dementia (70.1%).
The clinical management of the most common change after amyloid PET scans involved the prescription of AD drugs, which occurred in 43.6% of patients with MCI and in 44.9% of patients with dementia. Doctors also recommended counseling in 24.3% of MCI patients and in 20.7% of dementia patients. The PET results significantly influenced the management in 85.2% of the cases where a change was made, the investigators reported.
The results of amyloid PET were negative (only for the retention of white matter) in 36% of people with presumed aetiology of AD before PET; they were positive, however, in 52% of people with presumed non-AD pre-PET aetiology.
The non-randomized design of the study and the fact that the investigators did not compare amyloid PET with other imaging biomarkers or Alzheimer's CSF were among the limitations of the study, the authors of the paper recognize. They also noted that the participants were aware that the PET results should have changed diagnosis and treatment, and most participants were non-Hispanic whites, which does not reflect the ethnic and racial diversity of Medicare beneficiaries in the United States.
The Alzheimer Association, the American College of Radiology, Avid Radiopharmaceuticals (a wholly owned subsidiary of Eli Lilly and Company), General Electric Healthcare and Life Molecular Imaging (formerly Piramal Imaging) funded the IDEAS process.
The Medicare and Medicaid service centers have repaid PET scans.
Dr. Rabinovici reported reports with Genentech, Eisai, Merck, Roche, Avid Radiopharmaceuticals and Eli Lilly and worked as an associate editor for JAMA Neurology. The co-authors report other relevant revelations in the complete study.
LINK FOR MORE INFORMATION:
Rabinovici GS, Catsonis C, Apgar C, et al. Association of amyloid positron emission tomography with consequent change in clinical management among health care recipients with mild cognitive impairment or dementia. JAMA 2019; Epub 2019 Apr 2.