Dementia diagnosis patterns in a racially diverse population within an integrated health delivery system

Topic: Risk, prevention and care in population studies

Abstract Background Although nearly 40% of older adults receive care in Medicare Advantage (MA) plans, there are limited information on whether the patterns of dementia diagnosis and health care utilization differ from traditional Medicare fee‐for‐service. We examined first ADRD diagnoses by provider type and clinical setting and compared patient socio‐demographic and clinical characteristics across a large integrated health care system in southern California. Methods Patients 65 years and older who were continuously enrolled in the health plan for at least one year prior to January 1, 2015 and had a first dementia diagnosis code during the study period (January 1, 2015‐ December 31, 2018) were included in the analysis. Providers classified as dementia specialists included neurologists, psychiatrists, and geriatricians; all other providers were considered nondementia specialists and mostly represented primary care. Data were derived from electronic health records. Results There were a total of 25,278 incident ADRD codes over the entire study period, slightly more than half assigned in ambulatory care and the remainder during a hospital‐based encounter. For the clinic‐diagnosed cohort (n=13,962), other than a slightly younger age for those diagnosed in neurology/psychiatry compared to geriatrics or primary care (79 vs. 82 years old), there were no other differences, including race/ethnicity or spoken language. Compared to the clinic cohort, the hospital‐diagnosed cohort (n=11,316) was slightly older (83 vs. 81 years old), more likely to be white (59% vs. 53%) and English speaking (90% vs. 85%); had more missed appointments (13% vs. 10%) and were more likely to have a non‐dementia cognitive impairment code in the two years prior (36% vs. 31%). They also had a higher burden of co‐morbidity (8.7 ± 3.8 vs. 7.0 ± 3.4) and higher rate of documented advance directive or POLST (49% vs. 41%) (all, p<.01). Conclusions Nearly half of the incident ADRD codes were associated with a hospital‐based encounter. Patients first diagnosed with ADRD in the hospital setting were generally older and sicker compared to patients diagnosed in the clinic. Given such differing socio‐demographic and clinical characteristics at diagnosis, claims based studies should distinguish patients first diagnosed in hospital vs. clinic‐based settings.

@article{nguyen2021-383db564,
  author  = {Nguyen, Huong Q. and Lee, Janet S. and Langer-Gould, Annette Magdalene and Borson, Soo},
  title   = {{Dementia diagnosis patterns in a racially diverse population within an integrated health delivery system}},
  journal = {Alzheimer s \& Dementia},
  year    = {2021},
  doi     = {10.1002/alz.049875},
  url     = {https://doi.org/10.1002/alz.049875}
}

Key findings

• Results There were a total of 25,278 incident ADRD codes over the entire study period, slightly more than half assigned in ambulatory care and the remainder during a hospital‐based encounter.
• For the clinic‐diagnosed cohort (n=13,962), other than a slightly younger age for those diagnosed in neurology/psychiatry compared to geriatrics or primary care (79 vs. 82 years old), there were no other differences, including race/ethnicity or spoken language.
• Compared to the clinic cohort, the hospital‐diagnosed cohort (n=11,316) was slightly older (83 vs. 81 years old), more likely to be white (59% vs. 53%) and English speaking (90% vs. 85%); had more missed appointments (13% vs. 10%) and were more likely to have a non‐dementia cognitive impairment code in the two years prior (36% vs. 31%).
• They also had a higher burden of co‐morbidity (8.7 ± 3.8 vs. 7.0 ± 3.4) and higher rate of documented advance directive or POLST (49% vs. 41%) (all, p<.01).
• Conclusions Nearly half of the incident ADRD codes were associated with a hospital‐based encounter.

Why it matters

In an integrated health system, 25,278 first dementia diagnoses were recorded, slightly more than half in ambulatory care and the rest during hospital encounters, with no racial/ethnic or language differences in the clinic-diagnosed group. This describes where and how diagnoses are made, not how the disease is treated, cured or prevented.

Study details

• Participants13,962
• Evidence strengthModerate

Read the original

• DOI: 10.1002/alz.049875
• Original source →
• Free full text: Alzheimer s & Dementia →

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

Related studies in Health systems and care delivery

• Dementia diagnosis and utilization patterns in a racially diverse population within an integrated health care delivery system Alzheimer s & Dementia Translational Research & Clinical Interventions · 2022-01-01 · usefulness score 55/100
• Early Alzheimer's disease patient care pathway and health system readiness: A framework for integrated care Alzheimer's & dementia (New York, N. Y.) · 2025-11-05 · usefulness score 36/100
• Brain health navigation in a large integrated healthcare system The journal of prevention of Alzheimer's disease · 2026-01-02 · usefulness score 35/100
• Antipsychotic prescribing patterns in a Medicare Advantage population of older individuals with dementia Journal of Mental Health · 2016-11-12 · usefulness score 40/100
• Reduction of concurrent use of highly anticholinergic medications in an integrated healthcare system: 2018–2021 Journal of the American Geriatrics Society · 2023-09-22 · usefulness score 33/100
• Health Care Costs of Alzheimer’s and Related Dementias Within a Medicare Managed Care Provider Medical Care · 2020-07-23 · usefulness score 54/100

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.

• Age-Related Cognitive Decline and Dementia: Interface of Microbiome–Immune–Neuronal Interactions The Journals of Gerontology Series A · 2025-02-27 · usefulness score 45/100 · Inflammation and the immune system
• Education and dementia in the context of the cognitive reserve hypothesis: a systematic review with meta-analyses and qualitative analyses PloS one · 2012-06-04 · usefulness score 73/100 · Prevention and risk
• Acute hospital dementia care: results from a national audit BMC geriatrics · 2016-05-31 · usefulness score 50/100 · Digital health tools

Similar studies

• Dementia Diagnosis Disparities by Race and Ethnicity 2021 · Disparities
• Over- and under-diagnosis of dementia in ethnic minorities: a nationwide register-based study 2011 · Disparities
• Improving access to dementia services for people from minority ethnic groups 2013 · Disparities
• Access to healthcare services and adherence to treatments for people with dementia among ethnic minority groups: a scoping review 2026 · Disparities
• Ethnic differences in the prevalence and pattern of dementia-related behaviors 2004 · Disparities
• Pathways to dementia diagnosis: evidence for cross-ethnic differences 2004 · Disparities

More on Health systems and care delivery

• A review that covers this ground Physical and mental health of homebound older adults: an overlooked population Journal of the American Geriatrics Society · 2010-11-10 · usefulness score 36/100
• 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 →