This story makes many of the mistakes typical of reports about tests intended to detect diseases early. It highlights potential and uNPRoven benefits, while largely ignoring the harms and costs.
The story contradicts itself by letting experts claim that early detection of Alzheimer’s Disease could allow people to delay the onset of dementia, while also acknowledging that there is no proven way to prevent or treat the disease.
As demonstrated by the examples of Huntington’s Disease, lung cancer, prostate cancer, cholesterol and other conditions for which treatment may not exist or is of uncertain effectiveness; testing healthy people is fraught with costs and harms. None of the serious consequences of testing are addressed in this “gee-whiz” story.
Perhaps the worst failure of this story is that it claims to report scientific news when all it actually does is trumpet a business deal. The medical science included in this story comes from journal articles published a year or more ago (not to mention the inclusion of claims about potential treatments which have not yet been tested in humans). The only news event was the announcement that a research institute had signed a development deal with a medical testing company.
It may “only be a business story,” but we think “even” shareholders should get the context, caveats and complete information about the harms and benefits of products.
This story includes only a vague cost estimate of “a few hundred dollars,” and allows a company representative to assert that it is much cheaper than brain scans without making any comparison to clinical methods for reaching a diagnosis of probable Alzheimer’s. The story does not address the likelihood of insurance covering this experimental test.
This story says that early detection of Alzheimer’s Disease could possibly alter the course of the disease. However, there is no therapy proven to slow Alzheimer’s; thus there is as yet no demonstrated benefit to testing healthy people for Alzheimer’s Disease. Even the statement that the test results would allow people to “plan their future” is questionable, since the test does not purport to offer a specific timetable for the development of symptoms. It seems that people would be told only to make the sorts of prudent family and estate planning that anyone should do regardless of the predictions of a test.
This test would have serious consequences, none of which are mentioned in this story.
As long as there is no effective treatment or preventive measures for Alzheimer’s Disease, the test would transform apparently healthy people into “pre-Alzheimer’s” patients condemned to their fate with no clear timetable and no options for effective action.
The assertion that people could “take steps to slow the disease, such as improving their diet and getting more "mental exercise"” is not supported by evidence of effectiveness.
Even worse, any test has both false positive and false negative results, meaning some people are likely to endure unnecessary anxiety, further testing and medical interventions that have risks, costs and side effects, while others will get false reassurance. There would be enormous social costs to a false positive that is never even mentioned in the article.
This story doesn’t even agree with itself about what the evidence is.
At one point it allows an institute scientist to claim that their test would allow people to slow the progression of Alzheimer’s; but then later it acknowledges that there is no proven treatment.
Also, the story refers to results of a trial of this test but left out critical information, including the fact that the trial enrolled only people with mental impairment and an existing diagnosis of “probable Alzheimer’s.”
But just as an X-ray can confirm lung cancer in a person coughing up blood – while being useless as a screening test for healthy people – the so-called accuracy claims for an Alzheimer’s test based on impaired patients may have very little relevance to the performance of a test in a healthy population.
(The trial results were published online in August 2008:
Khan, T.K., Alkon, D.L., Early diagnostic accuracy and pathophysiologic relevance of an autopsyconfirmed
Alzheimer’s disease peripheral biomarker. Neurobiol Aging (2008), doi:10.1016/j.neurobiolaging.2008.07.010)
The story goes on to allow the scientist to claim that an experimental treatment is “incredibly potent” even though it has not yet been through human clinical trials.
This story treats a prediction of Alzheimer’s risk as if it were actual impairment.
The story doesn’t answer the central question of why someone would get this test when there is currently no treatment that can alter the course of Alzheimer’s and not even a way to confidently determine a time frame for the onset of symptoms.
This story notes that the quoted scientist works for the institute developing this test and it includes comments from an independent expert.
This story mentions alternative methods for diagnosing Alzheimer’s Disease. However, by emphasizing the shortcomings of existing methods, while highlighting untested claims of superiority for the experimental test, this story makes an imbalanced comparison.
Specifically, the story claims this new test is 98% accurate. However, that figure comes from a small comparison of autopsy results in people who had been given a diagnosis of probable Alzheimer’s disease. Meanwhile, the story says that conventional evaluations of people with memory problems are “often wrong.” Because the groups of people being tested in these examples are different (one with clear signs of Alzheimer’s, the other with vague memory issues), it is wrong to draw a direct comparison.
This story prominently features an uncorroborated prediction by a company source about availability of this test, despite the many scientific and regulatory hurdles that would need to be cleared. What’s more, the quoted time frame for commercial availability of 12 to 18 months appears to contradict the institute’s news release statement that the development deal would last three years.
A journal article outlining the trial of this Alzheimer’s test was published online in August 2008.There are reports about the development of this test going back several more years.
The only news in this week’s announcement was about the financial deal between the institute developing this test and a medical testing company.
The story states that the lead scientist was interviewed. The quotes are not the same as in the institute news release. Also, an independent expert was quoted.
However, the timing of this story appears to rely entirely on the release of news about a financial deal. All of the science mentioned in the story was released months or years ago.
Systematic, Criteria-Driven
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