Identification of dementia: agreement among national survey data, medicare claims, and death certificates
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Updated: Jul 8, 2026

A Machine Learning Approach to Design an Efficient Selective Screening of Mild Cognitive Impairment
Published on: January 11, 2020
Truls Ostbye1, Donald H Taylor, Elizabeth C Clipp
1Department of Community and Family Medicine, Duke University Center for Health Policy, School of Nursing, Duke University Medical Center, Box 2914 Med Ctr, Durham, NC 27710, USA.
Objective:
To estimate the proportion of seniors with dementia from three independent data sources and their agreement.
Data Sources:
The longitudinal Asset and Health Dynamics among the Oldest Old (AHEAD) study (n=7,974), Medicare claims, and death certificate data.
Study Design:
Estimates of the proportion of individuals with dementia from: (1) self- or proxy-reported cognitive status measures from surveys, (2) Medicare claims, and (3) death certificates. Agreement using Cohen's kappa; multivariate logistic regression.
Principal Findings:
The proportion varied substantially among the data sources. Agreement was poor (kappa: 0.14-0.46 depending upon comparison assessed); the individuals identified had relatively modest overlap.
Conclusions:
Estimates of dementia occurrence based on cognitive status measures from three independent data sources were not interchangeable. Further validation of these sources is needed. Caution should be used if policy is based on only one data source.
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