Millions of Americans and their doctors are in the dark when it comes to early cognitive decline, according to a new study from the University of Southern California. A study published this week suggests that most general practitioners are significantly underdiagnosing mild cognitive impairment in their patients, after another recent study by the same authors found that millions of Medicare patients with the condition are falling through the cracks. Researchers say this diagnostic gap is concerning because it is important to detect and treat mild cognitive impairment before it becomes more severe.
It is well known that mild cognitive impairment is underdiagnosed in older people, but the researchers say their work is one of the first to quantify the current extent of the problem.
“It’s a whole different conversation when we can point to these numbers,” lead study author Soeren Mattke, director of the Brain Health Observatory at the USC Center for Economic and Social Research, told Gizmodo by phone.
In the latest study published On Tuesday in the Journal of Prevention of Alzheimer’s Disease, the team examined Medicare administrative data collected from over 200,000 primary care physicians and 50,000 practices between 2017 and 2019. They found that, on average, doctors and practices went undiagnosed about 92% of expected cases of mild cognitive impairment; They also estimated that only 0.1% of doctors made the diagnosis accurately as often as they should, based on expected rates.
In the previous article it was published In July of this year, authors 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.
According to other research, about 8 million of these Americans are likely to suffer from mild cognitive impairment, which is defined as noticeable memory loss or cognitive decline that does not yet interfere with a person’s daily activities. But although the rate improved slightly over time, only a small proportion of Medicare patients actually received a diagnosis of mild cognitive impairment during the study period, accounting for about 8% of expected cases.
In other words, at least 7.4 million Americans over 65 are unaware that they live with mild cognitive impairment, with the authors further estimating that up to 10 million Americans are undiagnosed if those over 50 are included.
Many, if not most, people experience some degree of cognitive decline as they age, and not every case results in significant problems. But often mild cognitive impairment is the first stage of a more serious neurodegenerative disease, particularly Alzheimer’s disease, the most common form of dementia. About 10% to 15% of these cases in people over 65 each year progress to full dementia, the study found Alzheimer’s Associationwhile a third of people with mild cognitive impairment due to Alzheimer’s will develop dementia within five years.
“At MCI, there is actually a proportion of cases that are easy to resolve – some can be caused by medication side effects or vitamin deficiencies, and we can take care of all sorts of things when cases are discovered,” Mattke said. “And we’re starting to see disease-modifying treatments that can potentially alter the course of degenerative diseases like Alzheimer’s.”
These treatments, like the ones now fully approved anti-amyloid drug Leqembifor now appear to offer at best modest clinical benefits. However, many experts believe that one day these drugs can be significantly improved and combined delay or stop the progression of Alzheimer’s disease and other dementias. To derive the maximum benefit from these treatments, it is necessary to detect cases of mild cognitive impairment as early as possible.
Mattke says there are readily available tests for cognitive decline, but they take time to administer (10 or more minutes). Many physicians may not feel compelled to screen for this in their older patients or may be too busy, and patients may not consider requesting screening until their impairment is much more advanced. Therefore, Mattke hopes his team’s research can help make both groups more aware and willing to address this growing health problem.
“The really important insight is that this diagnosis is a race against time,” Mattke said.