Diagnostic tests alone may not be enough to help determine a patient's risk of future cognitive decline, but a combination of biomarkers may just do the trick.
New research published May 15 in the Journal of the American Medical Association found that a combination of positive results of flutemetamol F 18–labeled PET data, low volume of the hippocampus and cognitive status is associated with a higher risk of progression from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease within 36 months.
Led by David Wolk, MD, from the Penn Memory Center at the University of Pennsylvania, researchers assessed 232 patients (118 women and 11 men with an average age of 71) with aMCI between Nov. 11, 2009, and Jan. 16, 2014.
PET imaging was conducted on all patients, and checkups were done every six months during the three-year study period. Patients were recruited from 28 clinical centers in Europe and the U.S.
Five blinded readers with no knowledge of clinical status read flutemetamol F 18–labeled PET scans, before statistical analysis was conducted.
The team found that aMCI patients with β-amyloid-positive scans were 2.5 times more likely to develop Alzheimer's disease within three years compared to those with negative scan.
"Adding the biomarkers of hippocampal volume and cognitive status to the model increased the risk of progression to 8.5:1 during the same observation period," the researchers wrote. "The study results support using β-amyloid PET to identify patients with aMCI who are at increased risk for relatively near-term progression to dementia. Furthermore, when used with MRI (routinely performed for these patients) and a standard psychometric measure of memory, more precision in the likelihood of progression may be achieved for a significant proportion of patients."