Alzheimer’s disease diagnosis is maturing, but not yet mature
Volume 7, Issue 13 | April 5, 2023
In This Issue
COVID national emergency will be first of the federal emergencies to go
Senators advocate for continued Medicare coverage of home COVID tests
MEGA index results for Q1 2023
New and Noteworthy
The end of federal COVID emergencies begins with a Senate vote
The Senate has voted to overturn the national emergency that was declared in response to COVID-19 back in March 2020 - and President Biden is expected to sign it. This emergency declaration is different from the two “public health emergency” declarations. The main thing the national emergency did was to allow the US Department of Health and Human Services to waive certain requirements for Medicare, Medicaid, and state Children’s Health Insurance Programs (CHIPs), mostly so that people wouldn’t have to leave their homes to get health care and hospitals could expand critical-care services.
In other signs of “The Beginning of the End” of national focus on the COVID pandemic, the Washington Post and the CDC are both ending their COVID newsletters. The New York Times ended their newsletter a while ago. Rest assured, we here at Sensitive & Specific are not going away and will keep coming to your inbox!
Medicare coverage of at-home COVID tests gets more advocates
A group of US Senators have sent a letter to HHS stressing the importance of continued Medicare coverage of at-home OTC COVID tests after the Public Health Emergency ends. (Medicare has said that they will continue to cover lab-based testing for COVID, consistent with other lab-based testing that Medicare covers.) The key sentence is, "Without coverage under Medicare, many older Americans will not be able to afford to pay out of pocket for these critical tests, and simply won’t test."
The letter also noted that the CMS is still conducting evaluation of their demonstration program focused on at-home tests, but that evaluation will not be completed before May 11. The Senators ask that CMS fully evaluate the program before deciding to end it. They also ask CMS for more information on what they’re doing to warn seniors that coverage is ending.
Commentary: As you have no doubt heard us say many times, testing is the only way to slow a surge. We understand that there are lots of political issues here, but we agree with the effort to expand testing coverage. If nothing else, the average reimbursement for a COVID at-home OTC test is now ~$12, while lab tests are ~ $50.
MEGA stock index remains lower than S&P in Q1 2023
Our MEGA diagnostics index looks at the stock performance of public diagnostics companies. As the above graph shows, diagnostic companies outperformed the S&P during 2020 and 2021. But the Omicron era at the start of 2022 ushered in a change, and diagnostic companies lost significant value against the broader market index. Q1 2023 has been a bit better, with a steadying of values.
Food for Thought
Alzheimer’s disease diagnostics: past infancy, but not yet mature
For the first 100 years after Alzheimer’s disease was first described, diagnosis required two findings: cognitive deficits and brain atrophy at autopsy. In the mid-2000’s PET brain scans for suspect protein plaques and tangles became available. But imaging can only provide a definitive answer long after the disease has progressed to a point at which currently available interventions have very limited benefits. (See this week’s Nature Feature for further details).
More recent attention has focused on finding reliable earlier biomarkers in cerebrospinal fluid (CSF), blood/serum, or - even better - in nasal swabs. A series of studies from Oskar Hansson’s lab in Sweden provide very encouraging data on the utility of detecting phosphorylated Tau217 in serum (neither this nor other blood/serum biomarkers have yet been commercialized).
But diagnostics even less invasive than that may be possible. A 2022 Bioengineering metastudy explained how changes in spontaneous speech can be a leading indicator of Alzheimer’s disease, and companies are now designing apps that evaluate speech patterns, looking for those that warrant further investigation. Another diagnostic approach for this and other neurodegenerative diseases is analysis of a person’s gait and gait variability: Can the person walk fluidly? If not, this change may be an early indication of a neurological disease.
There is no universal consensus on what really kicks off Alzheimer’s disease, nor for which aspects drive cognitive effects, since plaques and tangles are often found in many who suffer no cognitive deficit at all. (Other protein-misfolding dementias such as Parkinson’s and ALS have similar controversies.) Recent papers explore a wide range of nontraditional possible explanations: One suggests that Alzheimer’s may be an autoimmune disease akin to multiple sclerosis; another highlights links to prior viral infection (e.g., viral encephalitis).
Commentary: Now that the first treatments designed to tackle the root causes of Alzheimer’s disease are available (lecanemab/Leqembi from Eisai and aducanumab/Aduhelm from Biogen), the need for more effective and less-invasive diagnostics has become urgent. There is no question that over the next five years serum biomarker diagnostics will become better understood and clinically available. The demand will be high, because current therapies are likely to be more effective the earlier they can be used. Clinical trials desperately need tools to identify the correct populations to enroll. In addition, we believe that if a new generation of biomarkers are accurate and effective, there will also be more uptake of analytic observational markers, such as speech and gait, so-called “alternative diagnostics,” to create the pipeline of people who need biomarker tests.
Quick Hits
The World Health Organization has added a new subvariant to its “under monitoring” list: XBB.1.16 (aka Arcturus). Arcturus has replaced other subvariants in India, which last week reported its highest COVID levels in six months.
About 50% of cows in the US likely have antibodies to influenza D - and people can get infected with it, too. Right now, this virus doesn’t cause any symptoms in people - but it’s an example of how many more viruses may pass between humans and animals than we previously realized.
