Questions about the early diagnosis of Alzheimer’s disease

Alzheimer’s disease made headlines recently, first with news about a new biomarker test that is able to diagnose the disease with increased accuracy, then with a follow-up story detailing the collaborative model of data-sharing that contributed to the success of recent research.

As I read the news with interest I couldn’t help but feel that in our current climate, the manner in which it was reported was somewhat ironic. Just nine months ago experts on the United States Preventive Services Task Force argued that harm, in the form of anxiety related to the detection of breast abnormalities, was too excessive to warrant screening mammograms in forty-year-old women. Just think of the anxiety that will occur if we begin screening asymptomatic adults for Alzheimer’s disease.

The unfortunate reality is that despite recent gains in our ability to accurately diagnose Alzheimer’s disease, there is still no therapy that has proven effective in preventing its progression. On August 3, 2010 the Annals of Internal Medicine published a summary of this year’s National Institute of Health Preventing Alzheimer’s Disease and Cognitive Decline Conference.

Alzheimer’s disease, the most common form of dementia, is a critical field of study, given the impact that this condition will have on our aging population. At this point the main benefit of earlier and more accurate diagnosis of cognitive impairment and dementia is that it will promote more research on therapeutics on a population level. However, practically thinking, what about the burden that this type of diagnosis could have individuals who go through testing? Is it worthwhile to detect a condition early for which there is currently no definite effective therapy? What would have happened to Ronald Reagan had he had this spinal fluid test when he was sixty years old? Would he have run for president? Would we have elected him? The test may accurately predict Alzheimer’s, but does it tell us when? And will happen to health insurance or long-term care insurance coverage for patients after this test is performed?

MRI’s are an also an effective means for detecting changes related to Alzheimer’s disease, demonstrating amyloid plaque accumulation in patients with Alzheimer’s, and distinguishing these patients from those who have other types of dementia, such as vascular dementia, which might be managed differently. However, what about all of our talk of comparative efficacy? Has performing an MRI been shown to alter the outcome of patients with a cognitive impairment or dementia diagnosis? I doubt that it has. I hate to be a cynic, but who will pay for the spinal fluid test, and the MRI, and the neuropsychological testing? And then, the repeat MRIs, and biomarker tests, and neuropsychological tests when the results of the first tests are inconclusive? How frequently will these tests need to be done? These questions are at the heart of the reality that our country faces with respect to the role of medical progress, cost, and health care. But as a physician I advocate mainly for my patient, not for the health care system, so I make these diagnostic decisions collaboratively with my patients, not necessarily with the population level questions in mind.

The Alzheimer’s progress is a perfect example of how our country will have to grapple with balancing exciting innovation with the appropriate use of “evidence-based” diagnostics in the coming decade. But how will diagnostics ever become evidence-based if health plans refuse to pay for them? If industry finances expensive clinical trials, should we really be attempting to regulate the cost of their drugs?

In the wonderful book by Audrey Niffenegger, The Time Traveler’s Wife, the time traveler witnesses his future death. His fate is unalterable and torments him. Until there is more effective therapy, I, for one, will not be doing the Alzheimer’s test. Instead, I will do my best to remain mentally and physically active, control my cardiovascular risk factors, eat my vegetables, consider taking fish oil, take an 81 mg aspirin when I am 65, and wait to see what the next decade of Alzheimer’s research will bring in terms of therapeutics. Hopefully innovation will not be stifled by policy change within our country.

Juliet K. Mavromatis is an internal medicine physician who blogs at Dr Dialogue.

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  • SarahW

    No patience for the “anxiety” excuse. Patient’s are capable o determining what level of “anxiety” they will risk with a test that suggests dementia is coming right for them.

    Those who want to prepare have already borrowed enough trouble to care about what the future holds for themselves and the ones they love.

    Bucket lists filled, money matters managed, contingency plans for care… some people know it is better to know.

    Others will just let things happen.

    NOT YOUR CALL.

  • SarahW

    Certainly, an explanation of the limits of such tests is what should be offered. However, tolerance for uncertainty or degree of uncertainty worthy of the expense and trouble, is really subjective and very individual.

    Distorting this conversation is the hidden, real problem = who will pay. Again, this cost effectiveness question is not between patient and physician, but patient and bank account or patient and private insurer.

  • http://braintoday.blogspot.com/2010/08/retirement-and-alzheimers-disease.html Dennis Fortier

    While it is interesting to grapple with the philosophical repercussions of wide-spread screening, I think Dr. Mavromatis misses the key point of how a new diagnostic test for AD could be used. Today, physicians seeing patients who present with memory loss do not have a single, highly accurate test to determine, among the many known causes of memory loss, which one is at work in that particular patient. If such a bio-marker test could be developed and brought to market, then there is certainly an important, immediate, uncontroversial need to use it in clinical practice. This point is developed in the Brain Today blog at: http://braintoday.blogspot.com/2010/08/most-immediate-and-practical-use-for.html

  • http://www.drdialogue.com Juliet K. Mavromatis, MD

    Thank for your comments on my blog. I enjoyed reading “braintoday.” Lots of great information there. My blog is not just a “philosophica”l discussion, but a highly pragmatic one, meant to highlight the sorts of questions that will need to be addressed should a biomarker test for Alzheimer’s Disease come to market in the absence treatments that are very effective for this highly prevalent disease of the elderly. As Dennis Fortier points out 50% of 85-year-old patients may be affected. Primary prevention is much different than secondary or tertiary prevention; that is, testing patients who are asymptomatic versus those who already have symptoms (mild cognitive impairment) or dementia. Clearly using a collaborative approach to decision-making with patients and testing in patients who are symptomatic may be of benefit in terms of helping patients with advanced planning, etc. In my view, at this point in time, the main benefit of an AD test would be to identify patients who may participate in trials of therapeutics, which we desperately need. The fact is that resources ARE limited, and that my professional role as primary care physician IS to help advise individual patients about what testing is likely to result in therapeutics that are able to improve their clinical outcomes. With the advent of any new technology for prevention a whole series of questions need to be addressed: Who are we going to screen? At what follow-up interval? What additional tests will be required if testing is positive? How are we going to use the information to affect positive change in clinical outcomes?

  • Marie McHarry

    Having a father who died of slow devoloping AD, I welcome a test that could diagnose the disease early. We could have done much better planning had we known that Dad’s lapses weren’t just temporary.

    For myself. I want to know if I’ll be getting AD. I’m widowed and live alone. I don’t particularly want to end up as a pathetic old woman, dying in squalor and eaten by cats (not that the three geratric cats I have would make much headway).

  • http://www.MDWhistleblower.blogspot.com Michael Kirsch, M.D.

    Well done post, Juliet. (In other words, I agree with your view!). A diagnostic test for Alzheirmer’s would be extremely useful for medical research, but for general clinical use. Just because physicians can do something, doesn’t mean we should. As I see it, the harm of using such a test widespread is much greater than the potential benefit. Also, the test may not be failsafe. There might be a cohort with a ‘positive test’ who never develop overt disease for various reasons. Detecting susceptibility to a condition makes sense when you can alter the course of the anticipated illness.

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