As biomarkers to detect signals of Alzheimer disease improve at providing clinically meaningful information, a majority of Alzheimer researchers support disclosing results to research subjects who have these tests, according to the results of a new survey.
“Our survey of experts in amyloid imaging suggests that data from amyloid imaging is just one part of a multiattribute equation to measure a person’s brain’s health and prognosis,” co–senior author Jason Karlawish, MD, Professor of Medicine and Medical Ethics and Health Policy at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, told ConsultantLive.
“In a sense, the experts are borrowing from the models developed in other common diseases of aging, particularly diabetes, cardiovascular disease, and osteoporosis,” Dr Karlawish said. “In those diseases, clinical practice has moved from a focus on a single biomarker, such as blood pressure or bone mineral density, to integrating biomarkers and clinical measures into a multivariate equation whose output guides treatment.”
He added: “Neurodegenerative disease diagnostics are in a comparative infancy, but they are being born and raised in this new world of biomarker-based, algorithm-driven, personalized medicine.”
The study surveyed 139 Alzheimer disease clinical trial leaders and coordinators from the Alzheimer Disease Neuroimaging Initiative in April 2012, just before the FDA approved the amyloid-binding radiotracer known as Amyvid (florbetapir). About three-fourths of the respondents supported disclosing amyloid imaging results to study participants who had mild cognitive impairment, and a little more than half supported giving amyloid imaging results to those who had normal cognition.
The Society for Nuclear Medicine-Alzheimer Association Task Force recommends that amyloid imaging be prescribed only after an evaluation by a dementia expert. That typically is a neurologist, geriatrician, or psychiatrist who dedicates at least 25% of his or her practice to the workup of older adults with cognitive complaints, Dr Karlawish noted, adding, “Some primary care physicians, such as geriatricians, fit this category. Those who are not experts should cultivate a referral relationship with an expert.”
As longitudinal studies accumulate more and more data that explain how biomarkers chart the clinical course of cognitive decline in older adults, Alzheimer disease diagnostics will change, Dr Karlawish suggested. “A concept such as ‘preclinical Alzheimer disease,’ a concept not yet ready for clinical practice, shows how far the field is pushing the borders between what is normal aging and disease,” he said. “For now, and perhaps for many years, it remains in the hands of adventurous researchers.
“In such a revolutionary time, enthusiasm can overwhelm reasonable interpretations of data, confusion over the meaning of terms can lead to fights about core ideas, and patients and clinicians can get swept up in hype or despair,” Dr Karlawish added. “Now is the time for critical thinking about the data and to exercise patience for the results of clinical trials that are testing whether a drug that targets a biomarker, such as amyloid, changes the clinical course of persons who have that biomarker.”
The researchers reported their results online on August 21, 2013, in the journal Neurology.