title: Identification of dementia: agreement among national survey data, medicare claims, and death certificates.
abstract: 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.
authors.affiliation: 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.
authors.forename: Truls
authors.initials: T
authors.lastname: Ostbye
authors.forename: Donald H
authors.initials: DH
authors.lastname: Taylor
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Clipp
authors.forename: Lynn Van
authors.initials: LV
authors.lastname: Scoyoc
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Plassman
mesh_terms: 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