Most Would Rather Not Know Preclinical Alzheimer's Status

Daniel M. Keller, PhD

April 15, 2013

NICE, France — With the emergence of Alzheimer's disease (AD) biomarkers that include biomolecules in cerebrospinal fluid (CSF), brain imaging techniques, and increasingly sensitive cognitive testing, most individuals would prefer to remain in the dark about their preclinical AD status, new research shows.

A survey conducted by investigators at the Medical University of Lodz, Poland, and reported here at EPA 2013: 21st European Congress of Psychiatry showed that individuals' level of knowledge about AD influenced acceptance of testing to determine their risk and the desire to know their risk.

To gauge people's knowledge of the disease, willingness to undergo invasive or noninvasive tests, and preferences about informing them or relatives about test results, Tomasz Soboẃ, MD, PhD, associate professor in geriatric psychiatry and medical psychology, administered questionnaires to 68 cognitively intact elderly patients (aged 62 to 75 years), 49 related caregivers of AD patients (26 spouses, 23 adult offspring; aged 42 to 74 years), and 96 4th-year medical students. Knowledge of AD was assessed using the Alzheimer's Disease Knowledge Scale (ADKS).

Table. Biomarker Predictors of Alzheimer's Disease Risk

Biomolecules in CSF
Low amyloid-β1-42
High tau/pTau (hyperphosphorylated tau)
Imaging
High positron emission tomography (PET) amyloid tracer retention
Neuronal dysfunction on fluoreodeoxyglucose-PET
Neuronal dysfunction on magnetic resonance imaging (MRI)
Cortical thinning/hippocampal atrophy on structural MRI
Cognitive testing
Poor performance on challenging cognitive tests indicative of subtle cognitive decline

 

Medical students had more knowledge about AD than did healthy elderly or caregiver cohorts (mean ADKS scores: 23.4, 20.5, 21.3, respectively; P < .001). Adult offspring caregivers scored higher than spouse caregivers (P < .005).

"Interestingly, in all the analyzed groups, subjects who are willing to have tests...score considerably lower on ADKS, so the less they know about Alzheimer's, the more enthusiastic about testing they are," Dr. Soboẃ told meeting delegates.

In a general screening question about willingness to have diagnostic testing for AD in a preclinical, asymptomatic phase — knowing that there are no preventive or therapeutic strategies — medical students, the group most knowledgeable about AD, were the least accepting of undergoing diagnostic tests (32%), compared with 40% of healthy elderly and 44% of caregivers.

Medical students (40%) were also least likely to want testing even if they knew that a close relative had an established AD diagnosis compared with healthy elderly (55%) or caregivers (61%).

However, medical students' acceptance of diagnostic testing came closer (54%) but was still significantly different from that of healthy elderly (51%) and caregivers (61%) when presented with a scenario in which they had very mild but not bothersome symptoms that their doctors suspected may have represented an initial stage of AD.

Just about all the participants would agree to neuroimaging for diagnostic testing: 100% of medical students, 92% of healthy elderly, and 94% of caregivers. But when it came to lumbar puncture, healthy elderly (63% willing) and caregivers (56%) were more reluctant than medical students (85%).

Students (91%) would accept genetic testing more readily than healthy elderly (45%) or caregivers (41%). Dr. Soboẃ mentioned that in general, people in Poland are concerned about the privacy of the results of genetic testing.

Eighty-seven percent of healthy elderly, 56% of caregivers, and 94% of medical students responded that they would want to know the results of their diagnostic tests. However, 74% of healthy elderly, 64% of students, but only 41% of caregivers would want their results revealed to a close relative.

"This is really a strange result," Dr. Soboẃ said. "Caregivers are very hesitant" to have results disclosed to their relatives, presumably to spare them from the diagnosis of someone close to them.

In summary, Dr. Soboẃ said that a minority of study participants would agree to undergo diagnostic procedures for detecting preclinical AD.

"Having a close relative already diagnosed with dementia or experiencing subtle cognitive decline increased this fraction, and, independently of clinical scenario provided, their willingness of having these diagnostic procedures done is associated with lower ADKS scores, so lower knowledge of Alzheimer's disease," he said. "Taking into account these results, I think that progress in biomarker research and current diagnostic procedures are well ahead of possible consumer awareness and acceptance of these procedures."

Session chair Philippe Robert, MD, PhD, chairman of the memory center at Nice Sophia Antipolis University, who was not involved in the study, commented to Medscape Medical News that the topic of communicating preclinical AD on the basis of biomarkers is very important "because this is something which comes more and more frequently in our memory consultations all over Europe."

He said he feels that it is necessary to consider the point of view of the clinician as well as those of the patients and caregivers because their decisions can be influenced by the clinician's feelings about testing. Different individual physicians and particularly physicians in different specialties, for example, psychiatrists, neurologists, and geriatricians, may view testing with biomarkers differently. "So this must be taken into account," Dr. Robert advised.

The study had no commercial support. Dr. Soboẃ reported no financial relationships related to the presentation. In the past and in relation to other studies, he has reported research funding from Novartis, and he has been a speaker for companies, including Novartis, Pfizer, Eli Lilly, Sanofi Aventis, Merz, Lundbeck, Bristol-Myers Squibb, Janssen, and Servier. Dr. Robert reported no relevant financial relationships.

EPA 2013: 21st European Congress of Psychiatry. Abstract 1293. Presented April 7, 2013.

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