New research from the University of Southern California reveals that millions of Americans, along with their doctors, lack awareness of early cognitive decline. The study suggests that general physicians often under-diagnose mild cognitive impairment (MCI) in their patients. This follows a previous study from the same authors that found a significant number of Medicare patients with MCI go undiagnosed. The researchers emphasize the importance of recognizing and treating MCI before it progresses.
While it is known that MCI is often under-diagnosed in older individuals, this study quantifies the extent of the problem. “It’s a very different conversation to have when we can point to these numbers,” says senior study author Soeren Mattke, director of the Brain Health Observatory at USC’s Center for Economic and Social Research.
According to the study published in The Journal of Prevention of Alzheimer’s Disease, the researchers analyzed Medicare administrative data from over 200,000 primary care clinicians and 50,000 practices between 2017 and 2019. They found that doctors and practices failed to diagnose about 92% of expected MCI cases on average, and only 0.1% of physicians accurately diagnosed it as often as they should.
A previous paper published in the journal Alzheimer’s Research & Therapy examined the medical records of over 40 million Americans over 65 enrolled in Medicare and Medicare Advantage plans between 2015 and 2019. The authors estimated that around 8 million of these Americans should have MCI, but only 8% of the expected cases received a diagnosis.
Essentially, at least 7.4 million Americans over 65 are unaware that they have MCI, and including those over age 50, the number of undiagnosed cases could be as high as 10 million.
While not all cases of cognitive decline lead to serious issues, MCI is often the first stage of neurodegenerative disorders like Alzheimer’s disease. Approximately 10% to 15% of MCI cases in people over 65 progress to dementia annually, and one-third of those with MCI due to Alzheimer’s will develop dementia within five years.
MCI cases have potential “easy fixes” as some may be caused by medication side effects or vitamin deficiencies, according to Mattke. He also emphasizes the importance of early detection given the potential for disease-modifying treatments that can change the course of degenerative conditions like Alzheimer’s.
Although tests for cognitive decline are available, they are often overlooked or not prioritized by doctors and patients. Mattke hopes that this research brings awareness to the time-sensitive nature of MCI diagnosis.
