New studies suggest millions with mild cognitive impairment go undiagnosed, often until it’s too late

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Soeren Mattke, University of Southern California and Ying Liu, USC Dornsife College of Letters, Arts and Sciences

(THE CONVERSATION) Mild cognitive impairment – an early stage of dementia – is widely underdiagnosed in people 65 and older. That is the key takeaway of two recent studies from our team.

In the first study, we used Medicare data for about 40 million beneficiaries age 65 and older from 2015 to 2019 to estimate the prevalence of mild cognitive impairment in that population and to identify what proportion of them had actually been diagnosed.

Our finding was sobering: A mere 8% of the number of cases with mild cognitive impairment that we expected based on a statistical model had actually been diagnosed. Scaled up to the general population 65 and older, this means that approximately 7.4 million cases across the country remain undiagnosed.

In the second study, we analyzed data for 226,756 primary care clinicians and found that over 99% of them underdiagnosed mild cognitive impairment in this population.

Why it matters

Mild cognitive impairment is an early symptom of Alzheimer’s disease in about half of cases...