|January 14, 2011|
Accurate screening methods becoming more likely, but should they be offered?
A doctor, speaking from experiences in caring for the elderly, says “no.”
Tests to screen for Alzheimer’s disease (AD) seem to be getting more precise by the day: The most recent advance, published on Jan. 6 in the journal Cell, is a blood test that singles out antibodies linked to the neurodegenerative condition.
Specifically, the test is designed to find molecules generated by the body’s immune system to attack proteins associated with the disease, which afflicts 5.3 million Americans.
Although the procedure reported in Cell involved just 16 subjects diagnosed with likely AD, the Scripps Florida researchers who developed the test say that it was successful in identifying all but one of the Alzheimer’s patients. The team also noted even more impressive (but unpublished at this point) results in a Jan. 6 article in Nature: The test was 98 percent successful in identifying likely cases of the disease using a sample of 300 people.
If the test, and its precision, can be replicated, the procedure will raise hope as an accurate and relatively painless way to screen for AD in large numbers of people. If scientists are to ever develop truly effective treatments for Alzheimer’s, they will need to test those drugs in clinical trials on many individuals in which the disease is confirmed.
But as beneficial as a reliable test would be for research, its value in the doctor’s office is much less clear. That’s because there remains no effective treatment—much less a cure—for Alzheimer’s. People have very definite, opposing views on whether they would want advance knowledge of a disease that will ravage their brains and ruin their last years of life.
This was apparent in the various letters to the editor that the New York Times featured the day after the newspaper published an article about the dilemma that new diagnostic tools for AD presents: “Tests Detect Alzheimer’s Risks, but Should Patients Be Told?” (Dec. 17, 2010).
One of the letters was written by Dr. Thomas Finucane, a geriatrician and professor of medicine at the Johns Hopkins University School of Medicine.
“Thinking of elderly patients whom I’ve known for years, I am nearly certain that informing patients of the diagnosis of Alzheimer’s disease as early as possible, or telling them of an increased risk of the disease, will be harmful on the whole,” Finucane’s letter began. “We don’t exactly know what Alzheimer’s disease is. There are lots of different kinds of dementia, and the concept of ‘normal’ human aging is very poorly understood.”
Finucane, a core faculty member at the Johns Hopkins Berman Institute of Bioethics, spoke more from the standpoint of a physician than as a scholar of medical ethics. While his letter did not explicitly mention “bioethics” at any point, Finucane nonetheless raised concerns that epitomize the difficulties in health care that the Berman Institute seeks to address.
In his original letter to the Times, Finucane noted that the first patient publicly killed by Jack Kevorkian had come to him because she’d been told she had Alzheimer’s. Although that was edited out, the Times ran this portion:
“Further, the harms can be serious; some patients may even consider assisted suicide. Several studies have been done about patients who are worried that they have Alzheimer’s. There is very real suffering involved in the anticipation, and the suffering can begin years before there is any demonstrable abnormality or disability. The diagnosis is sometimes and inexplicably shameful.”
The Times article focused on M.R.I. brain scans and spinal taps, both invasive procedures that are about 90 percent accurate in diagnosing AD. However, the only way to definitively confirm the disease is to search for the gnarled plaques and tangles of proteins in the brain that are associated with Alzheimer’s—after the person has died.
So, even today’s most promising tests are still inconclusive—although they represent science’s best efforts to date. That said, a 100-percent accurate screening method for AD as cheap and (relatively) painless as a blood test would have immense value in the search for promising treatments.
Thomas Kodadek, a chemistry professor at Scripps who led the team that developed the blood test, acknowledges that the accuracy of their blood test must still be proven on a larger sample of subjects. And at this early stage, the team says the assay would best be conducted in combination with other methods of detecting Alzheimer’s to confirm diagnosis.
Just this week, another possible tool was announced by Finucane’s colleagues at Hopkins: an online assessment intended for seniors who feel they are at risk of developing dementia. The assessment is being refined and validated, and it is not meant to replace a full evaluation from a doctor, according to the tool’s developers.
Instead they consider it a scientific way to help a person educate him or herself about a disease that some doctors now believe is best managed if caught early. “Alzheimer’s disease and other types of dementia don’t just creep up on you. They’re incubating for decades in the brain,” said Jason Brandt, a professor of psychiatry and behavioral sciences at the Johns Hopkins School of Medicine who helped develop the assay.
But Finucane sees things differently: “If I am to get Alzheimer’s at age 70, at what age would I like to know this?” he asks at the end of his letter. “Never. I would like to notice at age 75 that my wife and kids are becoming at once oddly solicitous and a bit patronizing.”
Editor’s note: In follow-up thoughts that Finucane shared with the Berman Institute Bioethics Bulletin, he said that, in the studies of current Alzheimer’s drugs, patients and their caregivers generally cannot tell the difference between drug and placebo. And, billions of dollars are spent annually in the United States because of effective promotion of the drugs to physicians, patients and families, he added.
“Many people now take the drugs for ‘minimal cognitive impairment,’ although there is no benefit at all,” Finucane said. “If you tell another few million people that they have very early Alzheimer’s, might have it, or are at increased risk of getting it, the benefit to the drug companies will be huge—billions of dollars will be spent by people who aren’t really sick to buy drugs that don’t really do anything.”