LOS ANGELES (CNS) — In the first large study to examine the diagnosis of dementia in older Americans over time, researchers, including from USC, found the vast majority never meet with a dementia specialist and are instead overwhelmingly diagnosed and cared for by non-specialists, according to a statement released by the university.

Researchers at USC, Johns Hopkins and the University of Washington used Medicare data to track dementia diagnoses of nearly a quarter of a million people over five years. The team found 85% of individuals first diagnosed with dementia were diagnosed by a non-dementia specialist physician, usually a primary care doctor, and an “unspecified dementia” diagnosis was common.

One year after diagnosis, less than a quarter of patients had seen a dementia specialist. After five years, the percent of patients had only increased to 36%.

The study, which also found the use of dementia specialty care was particularly low for Hispanic and Asian patients, was published today in “Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.”

“Dementia specialists are more familiar with subtypes of dementia and may be less likely, for example, to misdiagnose Lewy body dementia as Alzheimer’s disease and wrongly prescribe antipsychotic medications to patients,” said co-author Julie Zissimopoulos, director of the Aging and Cognition program at the USC Schaeffer Center for Health Policy & Economics.

Using a large Medicare dataset, researchers examined the types of physicians that diagnose dementia, what dementia subtype diagnoses were initially provided and how they changed over time, the extent to which individuals accessed specialty care and how it varied by gender, race and ethnicity.

They found that, among those diagnosed by a non-dementia specialist, 33% of patients were given a diagnosis that lacked a specific type of dementia, compared to 22% of patients diagnosed by a specialist. Diagnoses of Alzheimer’s disease among patients who saw a specialist within the first year of diagnosis were higher at 42% compared to 29% among those who did not see a specialist.

Dementia specialists include neurologists, psychiatrists, neuropsychiatrists and geriatricians.

“Without identification of dementia type, patients and their families are potentially missing out on important discussions about care and managing this diagnosis with other chronic conditions, as well as information about clinical trials,” Zissimopoulos said.

The team also found Hispanic and Asian patients were less likely to have a follow-up visit about the diagnosis compared to white and African-American patients. Approximately 37% of Hispanics and 40% of Asians with an initial diagnosis had no follow-up care within the first year of diagnosis, compared to whites and African Americans who each had a rate of about 33%.

The research team said more study is needed to identify factors driving these differences, such as severity at diagnosis, complexity of the care and barriers or differences in seeking care from specialists.