A new study says we may soon be able to take a simple blood test to find out if we have Alzheimer’s, even years before there is any sign of symptoms.
This report fairly describes a promising but not imminent blood test that may be able to identify people with Alzheimer’s disease. It does a good job, particularly in a broadcast piece, of describing how the study was conducted and its potential implications.
The story could have been significantly stronger, however.
The ABC News website has a much more complete report on the study. The broadcast segment should have referred viewers to it.
Because the test is not available and will not be for sometime, estimating a cost of testing is not possible at the present time. But a story like this also could have touched on the issue of the downstream costs associated with testing everyone with signs of memory loss – which could be enormous – and the costs of providing what are now relatively ineffective current drug treaments.
The report says that the test is 90 percent accurate in identifying or predicting Alzheimer’s. But it fails to put what sounds like an extraordinarily powerful result in context. The groups studied were very small: In one result (according to other press reports), 38 out of 42 patients were correctly identified via the 18 proteins. Another result showed accuracy in 20 out of 22 patients.
The segment opens and closes with the hosts discussing whether there are harms (or even value) of knowing one will develop, or already has, Alzheimer’s disease, because there is no treatment available. The four people interviewed on the street emphasize the question of the test’s ultimate value. (See note below under "Sources of Information" for more on this tactic, however.)
Mixed review. The segment does a good job, particularly in a broadcast setting, of describing how the research was conducted (studying blood samples of the diagnosed and the impaired to find the related cluster of 18 "communication" proteins).
However, the story didn’t discuss a key limitation: the size of the study group. (See note under "Quantification of Benefits," below).
And it didn’t discuss another specific limitation of this study: this case-control type of patient selection almost always overestimates test accuracy. So it’s likely to perform worse in real world populations.
The story also didn’t comment on the fact that the publication in the journal Nature Medicine was actually a letter – which is curious and almost demands comment. Although methods are published, why was it not published as an original article about original research? As a letter, was it peer-reviewed? The same as original articles?
What’s missing is just as important as what was included, and for that reason, we rate this unsatisfactory.
The segment does nothing to exaggerate the effects or risk of Alzheimer’s, and does not raise false hopes about the ultimate value of the test.
The report also does an excellent job of refusing to oversell the potential benefits of existing Alzheimer’s drugs and other current treatments for the condition.
The segment falls short in this category in three ways:
It fails to report where the study was published (the British journal Nature Medicine).
The report fails to disclose some obvious conflicts of interest. Four of the authors have commercial ties to the company that developed the test. The main investigator did early work on the test when he was with the company, Satoris Inc., of which he is co-founder with another author of the paper. The lead author is a paid consultant to the company; so was another author of the paper. This information is available in the press release.
The person-on-the-street interviews do not provide valuable sources. Whether one wants to know about an Alzheimer’s diagnosis is a complicated question that requires a lot of information: the impact on estate planning and long-term care, the benefits (if any) of drugs in early stage treatment, how progress might be slowed or stalled by lifestyle changes, and more. It’s clear none of these people was well informed enough to have a meaningful opinion.
An interview with an Alzheimer’s clinician, or a caretaker, would have been more valuable. This would have helped viewers understand what role this screen could someday play in the context of typical treatment and care.
The segment states that no other blood tests are currently available. While this is true, spinal taps and imaging devices are being studied and used for diagnosis currently.
It would have been helpful to have some detail on what the host calls the "long and difficult process" of clinical diagnosis currently in use. Many viewers are likely to have a relative they are concerned about and would benefit from a clinician’s perspective.
The segment makes clear that the test is not currently available, is uncertain to be approved for use, and that such use would be several years away.
The intro briefly implies something more imminent, however.
The broadcast implies novelty early on in the set-up. But in his first statement the reporter indicates that this is "another in a series of blood tests proposed to diagnose Alzheimer’s." He then explains how this one is different, by studying 18 "communication" proteins.
Generally the piece does a good job of indicating that if this test is validated and comes to market first, it would be novel.
There is no evidence the report draws excessively on the press release. In fact (see next item) this is a case where the press release included vital information the story left out.