Case Definition for Diagnosed Alzheimer Disease and Related Dementias in Medicare

Topic: Risk, prevention and care in population studies

Of the 60 000 869 beneficiaries included (50 853 806 aged 65 years or older [84.8%]; 32 567 891 female [54.3%]; 5 555 571 Hispanic [9.3%]; 6 318 194 non-Hispanic Black [10.5%]; 44 384 980 non-Hispanic White [74.0%]), there were 4 312 496 (7.2%) with highly likely ADRD, 1 124 080 (1.9%) with likely ADRD, and 2 572 176 (4.3%) with possible ADRD, totaling more than 8.0 million with diagnostic evidence of at least possible ADRD. These beneficiaries were older, more frail, more likely to be female, more likely to be dual-eligible, more likely to use long-term care, and more likely to die in 2019 compared with beneficiaries with no evidence of ADRD. These differences became larger when moving from the possible ADRD group to the highly likely ADRD group. Mean (SD) FFS monthly spending was $2966 ($4921) among beneficiaries with highly likely ADRD compared with $936 ($2952) for beneficiaries with no evidence of ADRD. Differences persisted after age standardization. Conclusions and Relevance: This cross-sectional study of 2019 Medicare beneficiaries identified more than 5.4 million Medicare beneficiaries with evidence of at least likely ADRD in 2019 using the diagnostic case definition. Pending validation against clinical and other methods of ascertainment, this approach can be adopted provisionally for national surveillance.

Key findings

• Of the 60 000 869 beneficiaries included (50 853 806 aged 65 years or older [84.8%]; 32 567 891 female [54.3%]; 5 555 571 Hispanic [9.3%]; 6 318 194 non-Hispanic Black [10.5%]; 44 384 980 non-Hispanic White [74.0%]), there were 4 312 496 (7.2%) with highly likely ADRD, 1 124 080 (1.9%) with likely ADRD, and 2 572 176 (4.3%) with possible ADRD, totaling more than 8.0 million with diagnostic evidence of at least possible ADRD.
• These beneficiaries were older, more frail, more likely to be female, more likely to be dual-eligible, more likely to use long-term care, and more likely to die in 2019 compared with beneficiaries with no evidence of ADRD.
• These differences became larger when moving from the possible ADRD group to the highly likely ADRD group.
• Mean (SD) FFS monthly spending was $2966 ($4921) among beneficiaries with highly likely ADRD compared with $936 ($2952) for beneficiaries with no evidence of ADRD.
• Differences persisted after age standardization.

Why it matters

This study describes a method for identifying Medicare beneficiaries who have diagnostic evidence of Alzheimer's disease and related dementias using claims data. It does not test any treatment, cure, or prevention, and the authors say the method needs validation before being adopted for national surveillance.

Study details

• Study designcross-sectional
• Effect size84.8%; 54.3%; 9.3%
• Evidence strengthLow

Read the original

• DOI: 10.1001/jamanetworkopen.2024.27610
• PubMed: 39226058
• Original source →
• Free full text: JAMA Network Open →

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

@article{gianattasio2024-39226058,
  author  = {Gianattasio, Kan Z. and Wachsmuth, Jason and Murphy, Ryan Anne and Hartzman, Alex and Montazer, Jaleh S. and Cutroneo, Erin and Wittenborn, John S. and Power, Melinda C. and others},
  title   = {{Case Definition for Diagnosed Alzheimer Disease and Related Dementias in Medicare}},
  journal = {JAMA Network Open},
  year    = {2024},
  doi     = {10.1001/jamanetworkopen.2024.27610},
  pmid    = {39226058},
  url     = {https://doi.org/10.1001/jamanetworkopen.2024.27610}
}

Studies this one cites

Referenced by this study and also in the alzhub library, so you can read them here.

• The global prevalence of dementia: a systematic review and metaanalysis Alzheimer's & dementia : the journal of the Alzheimer's Association · 2013-01-01 · usefulness score 78/100 · Caregiving
• Contribution of Alzheimer disease to mortality in the United States Neurology · 2014-03-05 · usefulness score 72/100 · Caregiving
• Prevalence and determinants of undetected dementia in the community: a systematic literature review and a meta-analysis BMJ open · 2017-02-03 · usefulness score 68/100 · Getting a diagnosis
• Inequalities in dementia incidence between six racial and ethnic groups over 14 years Alzheimer's & dementia : the journal of the Alzheimer's Association · 2016-02-11 · usefulness score 62/100 · Disparities
• Trends in Relative Incidence and Prevalence of Dementia Across Non-Hispanic Black and White Individuals in the United States, 2000-2016 JAMA neurology · 2021-03-01 · usefulness score 59/100 · Disparities
• 2022 Alzheimer's disease facts and figures Alzheimer's & dementia : the journal of the Alzheimer's Association · 2022-03-14 · usefulness score 57/100 · Getting a diagnosis
• The accuracy of Medicare claims as an epidemiological tool: the case of dementia revisited Journal of Alzheimer's disease : JAD · 2009-01-01 · usefulness score 55/100 · Getting a diagnosis
• Racial disparities and temporal trends in dementia misdiagnosis risk in the United States Alzheimer's & dementia (New York, N. Y.) · 2019-12-09 · usefulness score 50/100 · Disparities
• Cross-cultural differences in dementia: the Sociocultural Health Belief Model International psychogeriatrics · 2012-12-14 · usefulness score 41/100 · Disparities

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1 news article on alzhub's news page cites this paper.

• Review of Medicare data reveals potential new statistics on dementia diagnosis NIH National Institute on Aging · March 13, 2025

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