Heterogeneous responses to risk-adjustment reform: evidence from dementia diagnosis in Medicare Advantage

Topic: Risk, prevention and care in population studies

Incident dementia diagnoses increased in MA relative to traditional Medicare, despite an overall downward trend in diagnosis rates. Increases were larger among enrollees in MA health maintenance organization plans (20.8%) than in preferred provider organization plans (7.6%) and varied across insurers, ranging from 7.2% (United Healthcare) to 21.6% (Kaiser Permanente). Increases were more pronounced in urban than in rural areas. Reintroducing ADRD into the MA risk-adjustment model was associated with increased diagnostic coding, with substantial variation across plan types, insurers, and geographic contexts. Because ADRD diagnoses increase risk-adjusted payments, larger increases across some plans may reflect coding practices rather than true disease prevalence, highlighting the need for closer monitoring.

@article{haye2026-42516522,
  author  = {Haye, Sidra and Jacobson, Mireille and Zissimopoulos, Julie},
  title   = {{Heterogeneous responses to risk-adjustment reform: evidence from dementia diagnosis in Medicare Advantage}},
  journal = {Health Affairs Scholar},
  year    = {2026},
  doi     = {10.1093/haschl/qxag167},
  pmid    = {42516522},
  url     = {https://doi.org/10.1093/haschl/qxag167}
}

Key findings

• Incident dementia diagnoses increased in MA relative to traditional Medicare, despite an overall downward trend in diagnosis rates.
• Increases were larger among enrollees in MA health maintenance organization plans (20.8%) than in preferred provider organization plans (7.6%) and varied across insurers, ranging from 7.2% (United Healthcare) to 21.6% (Kaiser Permanente).
• Increases were more pronounced in urban than in rural areas.
• Reintroducing ADRD into the MA risk-adjustment model was associated with increased diagnostic coding, with substantial variation across plan types, insurers, and geographic contexts.
• Because ADRD diagnoses increase risk-adjusted payments, larger increases across some plans may reflect coding practices rather than true disease prevalence, highlighting the need for closer monitoring.

Why it matters

This study found that new dementia diagnoses in Medicare Advantage increased after Alzheimer's disease and related dementias were reintroduced into the risk adjustment model, with variation across plan types and insurers. It notes that larger increases may reflect coding practices rather than true disease prevalence, and it is not about treating, curing, or preventing Alzheimer's disease.

Study details

• Effect size20.8%; 7.6%; 7.2%
• Evidence strengthLow

Read the original

• DOI: 10.1093/haschl/qxag167
• PubMed: 42516522
• Original source →
• Free full text: Health Affairs Scholar →

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

Studies this one cites

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

• Estimating the Prevalence of Dementia and Mild Cognitive Impairment in the US: The 2016 Health and Retirement Study Harmonized Cognitive Assessment Protocol Project JAMA neurology · 2022-12-01 · usefulness score 71/100 · Getting a diagnosis
• Racial and ethnic differences in trends in dementia prevalence and risk factors in the United States Alzheimer's & dementia (New York, N. Y.) · 2018-10-05 · usefulness score 51/100 · Prevention and risk
• Medicare Advantage Enrollment and Disenrollment Among Persons With Alzheimer Disease and Related Dementias JAMA Health Forum · 2023-09-15 · usefulness score 51/100 · Health systems and care delivery
• Trends in Incident Dementia Diagnosis Before and After Medicare Risk Adjustment JAMA Network Open · 2023-12-15 · usefulness score 50/100 · Health systems and care delivery
• Risk Adjustment for Alzheimer Disease and Related Dementias in Medicare Advantage and Health Care Experiences JAMA Network Open · 2026-03-13 · usefulness score 46/100 · Health systems and care delivery
• Variations in Medicare Advantage Switching Rates Among African American and Hispanic Medicare Beneficiaries With Alzheimer’s Disease and Related Dementias, by Sex and Dual Eligibility The Journals of Gerontology Series B · 2022-09-08 · usefulness score 45/100 · Health systems and care delivery
• Estimates of diagnosed dementia prevalence and incidence among diverse beneficiaries in traditional Medicare and Medicare Advantage Alzheimer s & Dementia Diagnosis Assessment & Disease Monitoring · 2023-07-01 · usefulness score 45/100 · Health systems and care delivery
• After Risk-Adjustment Change, Dementia Diagnoses Increased In Medicare Advantage Relative To Traditional Medicare Health Affairs · 2025-01-01 · usefulness score 40/100 · Health systems and care delivery

Related studies in Health systems and care delivery

• Changes to Medicare Advantage Risk Adjustment and Dementia Diagnosis in Older Adults Alzheimer s & Dementia · 2024-12-01 · usefulness score 33/100
• Evaluating The Accuracy Of Medicare Risk Adjustment For Alzheimer’s Disease And Related Dementias Health Affairs · 2022-09-01 · usefulness score 45/100
• Comparison of prior authorization across insurers: cross sectional evidence from Medicare Advantage BMJ · 2024-03-07 · usefulness score 49/100
• Health care utilization before and after a dementia diagnosis in Medicare Advantage versus traditional Medicare Journal of the American Geriatrics Society · 2023-09-05 · usefulness score 55/100
• Consistency of a Dementia Diagnosis Between Systems for Patients Receiving Care Through the VA, Traditional Medicare, and Medicare Advantage Medical Care · 2026-06-04 · usefulness score 54/100
• Differences in Dementia Diagnosis Rates in Primary Care in Traditional Medicare and Medicare Advantage Alzheimer s & Dementia · 2024-12-01 · usefulness score 33/100

Also tagged “prevalence”

1,224 studies in the library carry the topic tag “prevalence”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 1,224 tagged studies.

• Tea, talk and technology: patient and public involvement to improve connected health ‘wearables’ research in dementia Research Involvement and Engagement · 2017-08-01 · usefulness score 45/100 · Health systems and care delivery
• Racial and ethnic differences in disease course Medicare expenditures for beneficiaries with dementia Journal of the American Geriatrics Society · 2024-03-20 · usefulness score 53/100 · Costs and economics
• Prevalence of dementia in the United States: the aging, demographics, and memory study Neuroepidemiology · 2007-10-29 · usefulness score 62/100 · Getting a diagnosis

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• Additional file 1 of National trends in the prevalence of dementia in Medicare Advantage and Traditional Medicare 2026 · Health systems and care delivery
• Performance of Claims-based Dementia Algorithms in Medicare Fee-for-service and Medicare Advantage Populations 2025 · Health systems and care delivery
• Potentially Inappropriate Medication Use Among Patients With Dementia in Traditional Medicare and Medicare Advantage 2025 · Health systems and care delivery
• Identification of prevalent dementia in Medicare Advantage encounters, compared with rigorous cohort assessments 2026 · Health systems and care delivery
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More on Health systems and care delivery

• A review that covers this ground Evidence-Based Nonpharmacological Practices to Address Behavioral and Psychological Symptoms of Dementia The Gerontologist · 2018-01-01 · usefulness score 38/100
• Newest in this subject Family physicians' attitudes toward people with dementia and their association with empathy Research Square · 2026-10-14 · Preprint — not yet peer-reviewed · usefulness score 16/100
• Newest in this subject Performance of Claims-based Alzheimer’s Disease and Related Dementias Algorithms in Medicare Advantage and Fee-for-Service Populations The Journals of Gerontology Series A · 2026-09-17 · Peer-reviewed · usefulness score 52/100

See all studies in Health systems and care delivery →