Measuring Alzheimer's Disease and Other Dementias in Diverse Populations Using Medicare Claims Data.

We examined how methods used for identifying dementia in administrative claims affected dementia incidence across racial/ethnic populations using a 100% sample of Medicare beneficiaries (n = 23,793,452). We found levels differed by method from 3.1% annual incidence to 3.6% in 2014. Dementia incidence declined from 2007 to 2014, but choice of method differentially impacted levels and trends by race/ethnicity. Methods using codes for dementia diagnosis and drugs to treat symptoms identified proportionally more Hispanics and Asians with dementia than other race/ethnicities, while codes for dementia diagnosis, drugs, and symptoms identified proportionally more whites and American Indians/Alaska Natives with dementia than other race/ethnicities.