Temporal and Geographic Variation in the Incidence of Alzheimer's Disease Diagnosis in the US between 2007 and 2014

Noam Y. Kirson, Eric S. Meadows, Urvi Desai, Brian P. Smith, Hoi Ching Cheung, Peter Zuckerman, Brandy R. Matthews

Research output: Contribution to journalArticle

Abstract

OBJECTIVES: Our aim was to describe the incidence of Alzheimer's disease (AD) in the United States, overall and by geographic region. DESIGN: We conducted retrospective analyses of administrative claims data for a 5% random sample of US Medicare beneficiaries aged 65 years or older. AD incidence, defined as a diagnosis for AD (International Classification of Disease, Ninth Revision, Clinical Modification code 331.0×) in a given year, with no AD diagnosis in the beneficiary's entire medical history, was estimated for each calendar year between 2007 and 2014. Beneficiaries were required to be enrolled in Medicare for the calendar year of evaluation as well as the preceding 12 months. In addition, a cross-sectional assessment of geographic variation in AD incidence was conducted for 2014. For each population area (specifically, core-based statistical area, as defined by the US Census Bureau), AD incidence was estimated overall, as well as adjusted for differences in underlying patient demographics and metrics of access to care and quality of care. Changes in AD incidence from 2007 were also estimated. SETTING: US fee-for-service Medicare. Participants: US Medicare beneficiaries aged 65 years or older with no history of AD. RESULTS: Overall, the diagnosed incidence of AD decreased over time, from 1.53% in 2007 to 1.09% in 2014; trends were similar for most population areas. In 2014, the rates of AD incidence ranged from 0% to more than 3% across population areas, with the highest observed incidence rates in areas of the Midwest and the South. Statistical models explain little of the geographic variation, although following adjustment, the incidence rates increased the most (in relative terms) in rural areas of western states. CONCLUSION: Our findings are consistent with previously reported estimates of incidence of AD in the United States and its recent declining trend. Additionally, the study highlights the considerable geographic variation in the incidence of AD in the United States and suggests that further research is needed to better understand the determinants of this geographic variation.

Original languageEnglish (US)
JournalJournal of the American Geriatrics Society
DOIs
StateAccepted/In press - Jan 1 2019
Externally publishedYes

Fingerprint

Alzheimer Disease
Incidence
Medicare
Insurance Claim Review
Population
Social Adjustment
Fee-for-Service Plans
Quality of Health Care
Statistical Models
International Classification of Diseases
Censuses
Demography

Keywords

  • core-based statistical area
  • dementia
  • diagnosis rate
  • geographic variation

ASJC Scopus subject areas

  • Geriatrics and Gerontology

Cite this

Temporal and Geographic Variation in the Incidence of Alzheimer's Disease Diagnosis in the US between 2007 and 2014. / Kirson, Noam Y.; Meadows, Eric S.; Desai, Urvi; Smith, Brian P.; Cheung, Hoi Ching; Zuckerman, Peter; Matthews, Brandy R.

In: Journal of the American Geriatrics Society, 01.01.2019.

Research output: Contribution to journalArticle

Kirson, Noam Y. ; Meadows, Eric S. ; Desai, Urvi ; Smith, Brian P. ; Cheung, Hoi Ching ; Zuckerman, Peter ; Matthews, Brandy R. / Temporal and Geographic Variation in the Incidence of Alzheimer's Disease Diagnosis in the US between 2007 and 2014. In: Journal of the American Geriatrics Society. 2019.
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abstract = "OBJECTIVES: Our aim was to describe the incidence of Alzheimer's disease (AD) in the United States, overall and by geographic region. DESIGN: We conducted retrospective analyses of administrative claims data for a 5{\%} random sample of US Medicare beneficiaries aged 65 years or older. AD incidence, defined as a diagnosis for AD (International Classification of Disease, Ninth Revision, Clinical Modification code 331.0×) in a given year, with no AD diagnosis in the beneficiary's entire medical history, was estimated for each calendar year between 2007 and 2014. Beneficiaries were required to be enrolled in Medicare for the calendar year of evaluation as well as the preceding 12 months. In addition, a cross-sectional assessment of geographic variation in AD incidence was conducted for 2014. For each population area (specifically, core-based statistical area, as defined by the US Census Bureau), AD incidence was estimated overall, as well as adjusted for differences in underlying patient demographics and metrics of access to care and quality of care. Changes in AD incidence from 2007 were also estimated. SETTING: US fee-for-service Medicare. Participants: US Medicare beneficiaries aged 65 years or older with no history of AD. RESULTS: Overall, the diagnosed incidence of AD decreased over time, from 1.53{\%} in 2007 to 1.09{\%} in 2014; trends were similar for most population areas. In 2014, the rates of AD incidence ranged from 0{\%} to more than 3{\%} across population areas, with the highest observed incidence rates in areas of the Midwest and the South. Statistical models explain little of the geographic variation, although following adjustment, the incidence rates increased the most (in relative terms) in rural areas of western states. CONCLUSION: Our findings are consistent with previously reported estimates of incidence of AD in the United States and its recent declining trend. Additionally, the study highlights the considerable geographic variation in the incidence of AD in the United States and suggests that further research is needed to better understand the determinants of this geographic variation.",
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AU - Kirson, Noam Y.

AU - Meadows, Eric S.

AU - Desai, Urvi

AU - Smith, Brian P.

AU - Cheung, Hoi Ching

AU - Zuckerman, Peter

AU - Matthews, Brandy R.

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