Study links dementia diagnosis rates to geographic location

With new medications on the market or in the works for Alzheimer’s disease and other forms of dementia, a new study suggests that getting the diagnosis needed to access these new treatments may depend on where you live.

The percentage of people receiving a new dementia diagnosis each year varies widely across regions in the US, the study found.

And the differences between the country’s regions are even greater for people at the young end of the age range at risk for dementia, ages 66 to 74, and for those who are black or Hispanic.

The research shows that the same person is as much as twice as likely to receive a dementia diagnosis in some parts of the US as in others. The findings suggest that the likelihood of being diagnosed may have more to do with the healthcare system than individual factors that influence dementia risk.

A formal diagnosis is required to access advanced new tests and treatments for dementia. Many of them are aimed at slowing the progression of dementia in its earliest stages, also called mild cognitive impairment or mild Alzheimer’s disease.

The new study focuses on regional differences in the “diagnostic intensity” of dementia – the kind of difference that exists even after taking into account all kinds of risk factors for dementia and regional differences in population and health care.

It is conducted by a team at the University of Michigan and is published in Alzheimer’s and dementia: The Journal of the Alzheimer’s Association.

“These findings go beyond demographic and population differences in risk, and indicate that there are disparities at the health care level that can be addressed and resolved,” said Julie Bynum, MD, MPH, the UM Health geriatrician and health care researcher who led the study.

The message is clear: your likelihood of being diagnosed with dementia varies from place to place, driven by a variety of factors, from practice standards for healthcare providers to individual patient knowledge and care-seeking behavior. But the good news is that these are things we can take action on once we know where to look.”

Julie Bynum, MD, MPH, professor of internal medicine at UM Medical School

Bynum and her colleagues from UM and the Dartmouth College Geisel School of Medicine conducted the study using data from the records of 4.8 million people who were covered by traditional Medicare in 2019 and were older than 66 years.

They note that while nearly seven million Americans are currently diagnosed with dementia, millions likely have symptoms but no formal diagnosis.

Insurance coverage for new biomarker tests, brain scans and dementia-inhibiting medications depends on the diagnosis. But even for those who do not qualify, a confirmed diagnosis can be important in accessing specialized care and support for patients and their family members or friends who act as caregivers.

Going beyond risk factors: more about the research

Researchers have already identified many factors associated with an individual’s higher risk of developing Alzheimer’s disease and other forms of dementia. These include years of high blood pressure, high cholesterol, and tobacco or alcohol use, to lower levels of formal education, sleep, and social interaction.

But the new study shows for the first time that the differences in diagnosis by region are not explained by differences in the dementia risk level of different populations.

It looked at diagnoses within each of the 306 hospital referral regions developed for the Dartmouth Atlas of Health Care and used in many studies. Each HRR includes at least one hospital that can perform advanced heart and brain surgery; the researchers chose to use these regions because dementia diagnosis and advanced treatment also require specialized services.

In total, 143,029 of the people in the total population used in the study were diagnosed with Alzheimer’s or another form of dementia in 2019. The remainder of the 356,656 people in this population with that diagnosis had been diagnosed before 2019.

That means that overall, about 7% of people covered by traditional Medicare will have a diagnosis of dementia at some point, and 3% of this population will be diagnosed each year, with an average age at diagnosis of about 83 year.

The researchers then calculated the regional rates of new diagnoses and the total number of individuals diagnosed as of 2019 for each HRR. The prevalence of diagnosed dementia ranged from as low as 4% to as high as 14%, depending on the HRR, and the percentage of new dementia diagnoses in 2019 ranged from 1.7% to 5.4%.

They then looked at the numbers for three age groups – 66 to 74, 75 to 84 and 85 and older – and for people identified as white, black or Hispanic. They also included data on the percentage of the population in each HRR who had less than a high school education, who smoked, and who were obese or diabetic – all risk factors for dementia.

They also incorporated information on the overall intensity of all types of chronic disease diagnoses in each HRR.

By taking all these factors into account, the researchers were able to calculate a predicted diagnosis rate for new and total cases of Alzheimer’s and dementia for each HRR, and for individuals in each HRR. This is what they called diagnostic intensity.

Compared to the national average, 28% of people living in areas have the lowest intensity fewer are likely to be diagnosed, while 36% of people living in areas with the highest intensity more probably diagnosed.

The overall concentration of diagnosed cases of dementia was highest in the southern US, similar to the ‘stroke belt’ with a high risk of stroke and cardiovascular disease.

But the South was no longer a uniform hotbed of dementia diagnosis once researchers adjusted for the other factors.

Implications for regional changes

Bynum explains that the findings could reflect variations in clinical practice – for example, how often people are screened by their GP for early signs of dementia, or the availability of specialists to make a confirmed diagnosis.

Variation may also arise from cultural or personal differences in the extent to which an individual is likely to seek some form of care, schedule an appointment specifically because of memory problems, or report problems with memory or proactive thinking to a health care provider without doing so during treatment is requested. an existing agreement.

While the researchers cannot say for sure whether the variation reflects underdiagnosis or overdiagnosis, they do say that areas with lower-than-expected dementia diagnosis rates could use the new findings to see what barriers might be standing in someone’s way. be diagnosed.

“The goal today should be to identify people with cognitive problems earlier, but our data shows that the younger age group of Medicare participants is the one with the most variation,” Bynum said. “For communities and healthcare systems, this should be a call to action to spread knowledge and increase efforts to make services available to people. And for individuals, the message is that you may have to advocate for yourself to get what you need, including cognitive skills. checks.”

She adds that Medicare covers a cognitive screening during every enrollee’s annual wellness visit.

She also notes that the recent launch of Medicare’s GUIDE model for dementia care may provide a path to improving care. The model encourages clinical practices to better coordinate dementia care and provide 24-hour access to a trained caregiver.

In addition to Bynum, the study’s authors are Slim Benloucif and Jonathan Martindale of the UM Department of Internal Medicine, A. James O’Malley of Dartmouth College and Matthew A. Davis, Ph.D., of the UM School of Nursing and the Department Learning Health Sciences from the UM Medical School.

Bynum and Davis are members of the UM Institute for Healthcare Policy and Innovation, and leaders of the Center to Accelerate Population Research in Alzheimer’s, or CAPRA.

The study was funded by the National Institute on Aging of the National Institutes of Health (P01AG019783).