The Alzheimer’s Association set out new criteria for diagnosing and staging Alzheimer’s based on recent advancements, especially biomarkers that can biologically detect the disease instead of relying on clinical symptoms. But some are pushing back on the criteria.
The new criteria, which was published Friday in Alzheimer’s & Dementia, defines Alzheimer’s disease as a biological process that starts with changes in the brain prior to memory and thinking problems. As it progresses, people can display disorientation, memory loss, confusion or trouble planning. Symptoms in people with the disease can be due to other ailments, which is why it can’t be diagnosed based on clinical presentation alone.
The updates aren’t supposed to provide step-by-step clinical practice guidelines for clinicians or specific treatment protocols. Instead, they include general principles to inform diagnosis and staging of Alzheimer’s based on what the medical community knows about the disease, the authors noted.
“These updated criteria for diagnosis and staging of Alzheimer’s are driven by the latest developments and discoveries in Alzheimer’s science,” Maria C. Carrillo, PhD, Alzheimer’s Association chief science officer and medical affairs lead and senior author said in a statement. “Our goal in sharing them now — even as the field and our knowledge continues to evolve — is to advance diagnosis, treatment and prevention in order to improve individual care and reduce the societal impact of Alzheimer’s.”
Biomarker controversy
The criteria’s use of biomarkers, which are a key part of the criteria, have drawn scrutiny. The accuracy of some of the emerging Alzheimer’s blood tests needs to play a role in diagnosis and treatment, according to Clifford Jack, Jr., MD, the lead author from the Mayo Clinic. Biomarkers are intended to evaluate people with symptoms, not those without, the workgroup believes.
The authors grouped biomarkers into three broad categories: core biomarkers of Alzheimer’s disease neuropathologic change (ADNPC), non-specific biomarkers that are important in Alzheimer’s but are also involved in other brain diseases, and biomarkers of diseases/conditions that commonly co-exist with Alzheimer’s. Core Alzheimer’s biomarkers include those that become abnormal early on including amyloid plaques (amyloid PET; CSF Aβ 42/40 ratio, CSF p-tau181/Aβ 42 ratio, CSF t-tau/Aβ 42 ratio; or “accurate” plasma assays, such as p-tau217) as well as phosphorylated tau (biofluid and tau PET) that change later on in the progression of the disease, including aggregated tau proteins in the brain.
Some fear the new criteria could increase the number of people eligible for new drugs that come with serious risks. The presence of some biomarkers may not indicate the disease, some experts said.
“The Alzheimer’s Association should lose all credibility by releasing guidelines labeling perfectly normal people as having Alzheimer’s disease,” Adriane Fugh-Berman, MD, director of PharmedOut, a Georgetown University program monitoring pharmaceutical marketing strategies, told CNN.
“If followed, these guidelines will ruin the lives of tens of thousands of people who will be misinformed that they have dementia,” she said. “The only entities that gain from this travesty are the pharmaceutical companies that make drugs for Alzheimer’s and the Alzheimer’s Association, which is preying on fear.”
