Dr. Daniel Silverman
The findings come from the Metabolic Cerebral Imaging in Incipient Dementia study, an ongoing national clinical trial sponsored by the Centers for Medicare and Medicaid Services (CMS). The interim data show that patients whose doctors gleaned information from a brain PET scan performed with the tracer FDG — which measures energy being used throughout regions of the brain — did better over two years of follow-up than those whose doctors were randomized to not have access to the scan information.
“During the subsequent two years after their PET scans, these patients had superior executive function, better memory abilities and greater preservation of overall cognitive function,” said Dr. Daniel Silverman, a professor of molecular and medical pharmacology at UCLA and the study’s principal investigator.
The research, Silverman said, provides “the first direct evidence that patients whose early Alzheimer’s disease is revealed by FDG–PET will do better than patients with the same condition but with their brain metabolism pattern remaining unknown to their doctors and themselves.”
The findings from the study are being presented Sept. 26 at the Medical Biotech Forum in China.
Medicare currently does not reimburse for PET scans for patients who show signs of persistent cognitive decline but do not yet have dementia, Silverman said. By the time Medicare covers an FDG–PET scan — for which they reimburse about $1,200 per patient — significant damage, some of it irreversible, has already been done to the brain tissue.
Medicare currently is reexamining reimbursement policies for PET scans obtained in dementia cases, specifically with respect to amyloid imaging (which includes Alzheimer’s imaging). A national coverage decision is expected Oct. 1, Silverman said.
Prior to these study findings, there was no rigorously controlled scientific evidence on the long-term clinical benefit associated with obtaining PET scans, or any other kind of neuroimaging, in the evaluation of cognitively declining patients.
This multicenter, prospective, randomized and blinded study demonstrates significant clinical benefits, which may also save health care dollars.
“Patients who don’t have Alzheimer’s disease may be prescribed drugs that won’t help them or even make them worse,” Silverman said. “And each year of taking these medications costs hundreds of dollars more than the reimbursement for a PET scan would.”
Conversely, he said, undiagnosed Alzheimer’s patients won’t get the drugs that this study shows would help them, when given early, to maintain their cognitive abilities. These patients may ultimately need nursing home care six to nine months earlier than patients with the same brain pattern who were diagnosed and treated sooner as a result of the early availability of the PET scan information.
“With nursing home care costing an average of about $7,000 a month, there is the potential for CMS and American taxpayers to save several billion dollars per year,” Silverman said.
The interim results are based on an examination of 63 patients who underwent FDG–PET and neuropsychological testing at baseline. The testing and collection of medication-prescription data were repeated every six months for two years.
The doctors in the arm of the study who were able to view the PET scans immediately treated their patients differently than doctors in the arm that didn’t get scan results until the end of the two-year study. About 40 percent of the patients whose doctors were informed of the presence of the Alzheimer’s brain-metabolism pattern were given drugs specifically indicated for dementia within the first six months of the study.
Of the patients whose brain PET scans showed the Alzheimer’s metabolism pattern but who were randomized to the group whose scan results were delayed by two years, none were prescribed Alzheimer’s medications in the first six months, and only 12 percent were prescribed those medications by the end of the first year, Silverman said.
Medicare has approved the enrollment of 710 volunteers (at least 65 years old) for the study. Silverman said these interim results are being reported because the study had enrolled a sufficient number of subjects to allow for the first meaningful evaluation of the long-term impact of PET scans on early Alzheimer’s patients.
“Patients exhibiting Alzheimer’s-like neurodegenerative changes in cerebral metabolism were over three times more likely to be prescribed medications in the first year following PET when results of the scans were immediately released,” the abstract being presented at the meeting notes. “This, in turn, was associated with significantly better performance on neuropsychological tests of memory, executive function and general cognitive status over a two-year follow-up period. This study provides the first direct evidence for improved cognitive outcomes attributable to a neuroimaging test of any kind.”
Contact: Kim Irwin