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The Dementia DataHub analyzes Medicare Fee-for-Service (FFS) claims and Medicare Advantage encounter data to report the prevalence, incidence, and important outcomes of diagnosed dementia (including Alzheimer’s Disease and related dementias), at the national, state, and county level.
At the heart of this system are case definitions that use diagnosis and drug codes observed across three years of Medicare data to identify and classify dementia cases into three mutually exclusive categories:
In 2021, across all ages, we found that over 8.3 million Medicare beneficiaries, representing 13.3 percent of all enrollees, had evidence of Alzheimer's disease or related dementias based on any of the three categories, which was a 0.6 percent increase from 2020. Of these beneficiaries, 5.5 million (8.8 percent of enrollees) had at least one dementia-specific diagnosis code (at least Likely dementia) suggesting they likely had dementia, including 4.4 million who had two codes and are considered highly likely to have dementia. Among beneficiaries ages 65 and older, a total of 14.2 percent of beneficiaries had any evidence of dementia with 7.7 percent of beneficiaries categorized as highly likely (7.7 percent) or likely (1.9 percent) to have dementia, and 4.5 percent of beneficiaries categorized as possible dementia.
Considering only beneficiaries ages 65 and older, the incidence of dementia diagnosis in 2021 was 5.6 percent, a 0.6 percentage point increase from 2020. The annual mortality rate among beneficiaries ages 65 and older and diagnosed with dementia was 16.1 percent, a decrease of 1.7 percent points. Among beneficiaries ages 65 and older diagnosed with dementia, the prevalence of diagnosed COVID-19 infection was 13.6 percent, a decrease of 0.9 percentage points compared to 2020. Among beneficiaries ages 65 and older diagnosed with dementia in 2021 30.6 percent were hospitalized at least one time, 14.1% had a short-stay nursing visit, 9.4 percent had a long-stay nursing visit. Medicare beneficiaries aged 65 and older diagnosed with dementia experienced a rate of 501 hospital discharges per 1,000 beneficiaries in 2021. Among FFS beneficiaries ages 65 and older diagnosed with dementia, average all-cause Medicare payments were $26,270 per person in 2021, an increase of $1,500 percent compared to 2020. Data for hospitalization, hospital discharges, and short- and long-term nursing stays were not collected in 2020.
Our system provides data visualizations and public use files with information about the number and percentage of beneficiaries in each category that meet each case definition by demographic and geographic strata. While diagnosis codes are not as accurate as the gold-standard of physician ascertainment, and do not capture undiagnosed cases, when applied to national Medicare data they can provide nationally representative data on the burden, trends, and disparities in different outcomes of dementia at the state and county level.
The Dementia DataHub serves as a national statistics and data system focused on measuring the scope and outcomes of dementia in administrative data systems including Medicare. The project focuses on creating and validating case definitions to identify dementia, including Alzheimer’s disease and other related dementias using diagnosis and drug codes in billing claims and medical encounter data. The DataHub applies these case definitions to Medicare data to analyze and report national, state, and county measures of diagnosed dementia prevalence and incidence, and mortality, COVID-19 infections, and all-cause payments among people with prevalent dementia.
The Dementia DataHub is a joint effort led by NORC at the University of Chicago, with partner support from George Washington University’s Milken Institute School of Public Health and KPMG LLC. The DataHub is funded by the National Institutes on Aging through Grants R01-AG-075730 and R33-AG-094611.
Dementia DataHub estimates should be considered provisional, pending revisions and adjudications of administrative data records, and possible future revisions or enhancements to the system’s dementia case definitions.
The Dementia DataHub developed case definitions based on diagnosis and prescription drug codes to identify people diagnosed with dementia. We reviewed existing case definitions and categorized them based on their frequency of inclusion in prior case definitions. Expert input was used to remove certain codes from the case definitions. We are conducting ongoing validation studies to assess the accuracy of these case definitions. Therefore, case definitions may be revised over time as new information becomes available.
We developed our case definitions by aggregating codes used by 20 different previously published algorithms and the CMS Chronic Condition Warehouse definition, sorting by frequency of inclusion in prior case definitions, reviewing individual codes with clinical experts, and organizing codes into those that are directly related to dementia, Alzheimer's disease and other related dementias, and others that may indicate dementia but do not specifically state dementia or Alzheimer's disease. We used other Medicare evidence to provide support for these definitions.
We used 100 percent of the 2018, 2019 and 2020 Medicare fee-for-service (FFS) inpatient, outpatient, carrier, Skilled Nursing Facility (SNF), Home Health Agency (HHA), and hospice claims; Medicare Advantage (MA) inpatient, outpatient, carrier, SNF, and HHA encounter data; and Medicare Part D Prescription Drug Event (PDE) data.
Our estimates include any Medicare beneficiaries with at least Part A (the premium-free Medicare benefit) enrollment who was alive and enrolled as of January 1, 2021. We excluded people with missing sex, and invalid U.S. state or territory codes.
We applied the case definitions to included datasets using ICD-10 diagnosis codes and NDC drug codes in any position on the claim. We analyze and report outcomes by calendar year. To meet privacy suppression requirements (see below), estimated changes across years are only supported for age groups 65 and older. Estimates by race and ethnicity cannot be compared across years.
To ensure the privacy of individuals in Medicare, we suppressed any data cell value with a numerator or denominator count that was less than 11. We additionally suppressed related cells that could be used in combination to construct a cell count less than 11. Suppression is most extreme for results for the 0 to 64 category. To preserve the 65+ totals, we no longer produce estimates for those younger than 65 for any outcome other than prevalence.
All data used in this site are available for independent analysis as a public use file. If you are interested in accessing the public use data, please email the project team at Dementiadatahub@norc.org.
Prevalence indicated by both percentage and (count)
Prevalence indicated by count
Average payments indicated by dollar amount
