Many dementia patients don't report their diagnosis, study finds

by Meg Dalton, Yale University

edited by Lisa Lock, reviewed by Andrew Zinin

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Most research on the diagnosis of dementia focuses on people who are never diagnosed. But in a new study, Yale researchers look at the other side: people who have been diagnosed but do not know it or do not acknowledge it.

In an analysis of U.S. survey data from older Americans with probable dementia, the researchers found that about two-thirds (67%) of respondents who answered questions for themselves reported that no doctor had ever told them they had dementia, even though Medicare claims indicated such a diagnosis. That is far higher than for other conditions among the same people, such as high blood pressure (23%) or arthritis (17%).

Such levels of underreporting suggest that many of these patients are also likely not pursuing critical medical services related to their diagnosis, the researchers say.

"A diagnosis that sits in a chart but never registers with the patient delivers almost none of the benefits that early detection is supposed to bring," said Xi Chen, corresponding author of the paper and an associate professor of public health and economics at Yale University. The study is published in JAMA Network Open.

Many people with dementia go undiagnosed. While a few small, cross-sectional studies had previously suggested that even diagnosed patients are often unaware, nobody had tracked this over the course of the disease, compared it with other conditions in the same patients, identified who is most affected or asked whether it matters for the care people actually receive.

For the new study, researchers wanted to fill those gaps. They used the Health and Retirement Study, a nationally representative survey of older Americans that has followed the same people every two years since the 1990s and is linked to their Medicare claims. Using those data, they identified people 65 and older with probable dementia based on validated cognitive testing, then found the specific survey wave in which their Medicare records contained a dementia diagnosis.

The researchers checked whether the individuals reported, in that same period, that a doctor had told them they had dementia or a memory-related disease. They investigated the same information for four other conditions (arthritis, hypertension, diabetes, and depression) for comparison, examined which patient and health system factors predicted underreporting, and looked at whether underreporting was linked to doctor visits, flu shots, and having a will or trust in the year after diagnosis. In all, they analyzed thousands of observations from about 3,300 people.

Reducing stigma

Using their methods, the researchers found that two-thirds of self-reporting patients with a documented dementia diagnosis did not report it, compared with an average of about 31% for the other conditions. Underreporting was highest (82%) in the earliest years after diagnosis, before measurable cognitive decline, and was more common among people living alone, with less education or with lower incomes, and among Black older adults. It was less common among patients who saw a dementia specialist, were diagnosed in an outpatient clinic rather than a hospital, or were enrolled in Medicare Advantage, a comprehensive plan offered by some private companies as an alternative to traditional fee-for-service Medicare plans.

Patients who underreported were also about 30% less likely to visit a doctor for a health problem, 37% less likely to receive a flu shot, and 30% less likely to have a will or trust in the following year. Importantly, the same patients still reported their other conditions at normal rates, the researchers found, indicating that a lack of reporting is not due to memory loss.

Taken together, the findings suggest a mix of stigma, difficulty accepting the diagnosis and, above all, inadequate communication by the health system, the researchers said.

"Diagnosing dementia is only the first step," Chen said. "A diagnosis is only useful if the patient and family understand it and can act on it. Clinicians need the time, training and support to deliver this news clearly and compassionately, and patients and families should feel empowered to ask."

Chen added, "Reducing the stigma around dementia is a shared responsibility: the more openly we talk about it, the easier it becomes to accept a diagnosis and get the help that is available."

Publication details

Yuting Qian et al, Dementia Diagnosis Underreporting and Care Engagement and Planning Among Older Adults, JAMA Network Open (2026). DOI: 10.1001/jamanetworkopen.2026.31167

Journal information: JAMA Network Open

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NeurologyHealthy agingCommon illnesses & Prevention Provided by Yale University Who's behind this story?

Lisa Lock

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