title: Official statistics and claims data records indicate non-response and recall bias within survey-based estimates of health care utilization in the older population.
abstract: BACKGROUND
  The validity of survey-based health care utilization estimates in the older population has been poorly researched. Owing to data protection legislation and a great number of different health care insurance providers, the assessment of recall and non-response bias is challenging to impossible in many countries. The objective of our study was to compare estimates from a population-based study in older German adults with external secondary data.
  
  
  METHODS
  We used data from the German KORA-Age study, which included 4,127 people aged 65-94 years. Self-report questions covered the utilization of long-term care services, inpatient services, outpatient services, and pharmaceuticals. We calculated age- and sex-standardized mean utilization rates in each domain and compared them with the corresponding estimates derived from official statistics and independent statutory health insurance data.
  
  
  RESULTS
  The KORA-Age study underestimated the use of long-term care services (-52%), in-hospital days (-21%) and physician visits (-70%). In contrast, the assessment of drug consumption by postal self-report questionnaires yielded similar estimates to the analysis of insurance claims data (-9%).
  
  
  CONCLUSIONS
  Survey estimates based on self-report tend to underestimate true health care utilization in the older population. Direct validation studies are needed to disentangle the impact of recall and non-response bias.
authors.affiliation: Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Health Economics and Health Care Management, Ingolstädter Landstr, 1, Neuherberg, 85764, Germany. matthias.hunger@helmholtz-muenchen.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Hunger
authors.forename: Larissa
authors.initials: L
authors.lastname: Schwarzkopf
authors.forename: Margit
authors.initials: M
authors.lastname: Heier
authors.forename: Annette
authors.initials: A
authors.lastname: Peters
authors.forename: Rolf
authors.initials: R
authors.lastname: Holle
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015982:Bias; D002908:Chronic Disease / Q000628:therapy; D016001:Confidence Intervals; D004363:Drug Utilization; D005260:Female; D005858:Germany; D019538:Health Care Surveys / Q000592:standards* / Q000706:statistics & numerical data; D006296:Health Services / Q000706:statistics & numerical data*; D006801:Humans; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D008297:Male; D011939:Mental Recall; D016017:Odds Ratio; D057566:Self Report; D017678:Sex Distribution