Do Patients Want to Know Whether Alzheimer Disease Awaits Them?

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RESEARCH UPDATE

Interest in predictive testing for Alzheimer disease (AD) and advanced care planning is high among the general public, according to results of a survey-based cross-sectional study within the National Institute on Aging’s Health and Retirement Study (HRS).¹ Although research on accurate prediction of AD has been ramped up, predictive testing has yet to be made available-and the question looms as to whether a person would want to live with the knowledge that AD is waiting in the wings.

Because informal surveys have shown that the public has a keen interest in knowing AD risk status despite the prognosis, researchers from Stanford University and the University of California at San Francisco analyzed HRS 2012 data (Experimental Module 6) designed to speak to this issue.

The HRS is a nationally representative sample of community-dwelling adults, age 65 years and older, who are surveyed every 2 years. The researchers sought to find out who specifically would be willing to take a test predictive of future AD and whether testing would change behavior.

The 2 main outcomes assessed were willingness to take a test predictive of future AD and likelihood of completing an advance directive or living will if testing showed that development of AD was inevitable. For the first outcome, participants were asked: “If you could receive a test from your doctor, free of charge, that would definitely determine whether or not you would develop Alzheimer’s disease in the future, would you want to be tested?”

Although research on accurate prediction of AD has been ramped up, predictive testing has yet to be made available.

For the second outcome, the question posed was “If you knew you would develop Alzheimer’s disease in the future, how likely would you be to set up an advance directive or living will to let family members and doctors understand how you wish your health care to be managed?”

Participants were queried about self-perceived memory, health, and risk of AD and answers were compared against responses to the question regarding testing. Characteristics including demographics, physical functioning, and comorbidities also were analyzed in relation to survey responses.

A total 861 persons of the 874 surveyed responded to the question about willingness to take a free, definitive test predictive of future AD. Of these, 75% responded positively. No differences were seen between those willing or unwilling to take the hypothetical test in regard to race, educational level or perceived health status/AD risk, challenges related to activities of daily living, or number of comorbidities.

The only notable difference seen was that those who would decline testing were more likely to be younger (age 75 years or younger; odds ratio, 0.71 [95% confidence interval, 0.53-0.94]). Eighty-one percent reported that they would likely complete an advance directive if they knew AD was their fate, and 87% reported that they probably would discuss health plans with loved ones.

Clinical implications

The findings confirm high public interest in predictive testing for AD. However, the proportion of respondents who already had advance directives in place was low (15%), and other studies indicate that the proportion of persons who actually establish advance directives is low compared with the proportion who agree that having them is a wise decision. The researchers suggest that their findings may be used to encourage physician-patient discussion about advanced care planning.

References:

1. Sheffrin M, Stijacic Cenzer I, Steinman MA. Desire for predictive testing for Alzheimer's disease and impact on advance care planning: a cross-sectional study. Alzheimers Res Ther. 2016;8:55.