Identification of dementia: agreement among national survey data, medicare claims, and death certificates.
OBJECTIVE
To estimate the proportion of seniors with dementia from three independent data sources and their agreement.


METHODS
The longitudinal Asset and Health Dynamics among the Oldest Old (AHEAD) study (n=7,974), Medicare claims, and death certificate data.


METHODS
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.


RESULTS
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.
Ostbye
Truls
T
Department 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.
Taylor
Donald H
DH
Clipp
Elizabeth C
EC
Scoyoc
Lynn Van
LV
Plassman
Brenda L
BL
D000368:Aged; D032921:Consensus; D003627:Data Interpretation, Statistical; D003644:Death Certificates; D003704:Dementia / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007345:Insurance Claim Review / Q000706:statistics & numerical data*; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D006278:Medicare / Q000706:statistics & numerical data*; D012107:Research Design; D014481:United States / Q000453:epidemiology