title: Agreement between PRE2DUP register data modeling method and comprehensive drug use interview among older persons.
abstract: BACKGROUND
  PRE2DUP is a modeling method that generates drug use periods (ie, when drug use started and ended) from drug purchases recorded in dispensing-based register data. It is based on the evaluation of personal drug purchasing patterns and considers hospital stays, possible stockpiling of drugs, and package information.
  
  
  OBJECTIVE
  The objective of this study was to investigate person-level agreement between self-reported drug use in the interview and drug use modeled from dispensing data with PRE2DUP method for various drug classes used by older persons.
  
  
  METHODS
  Self-reported drug use was assessed from the GeMS Study including a random sample of persons aged ≥75 years from the city of Kuopio, Finland, in 2006. Drug purchases recorded in the Prescription register data of these persons were modeled to determine drug use periods with PRE2DUP modeling method. Agreement between self-reported drug use on the interview date and drug use calculated from register-based data was compared in order to find the frequently used drugs and drug classes, which was evaluated by Cohen's kappa. Kappa values 0.61-0.80 were considered to represent good and 0.81-1.00 as very good agreement.
  
  
  RESULTS
  Among 569 participants with mean age of 82 years, the agreement between interview and register data was very good for 75% and very good or good for 93% of the studied drugs or drug classes. Good or very good agreement was observed for drugs that are typically used on regular bases, whereas "as needed" drugs represented poorer results.
  
  
  CONCLUSIONS
  PRE2DUP modeling method validly describes regular drug use among older persons. For most of drug classes investigated, PRE2DUP-modeled register data described drug use as well as interview-based data which are more time-consuming to collect. Further studies should be conducted by comparing it with other methods and in different drug user populations.
authors: Kuopio Research Centre of Geriatric Care, University of Eastern Finland; School of Pharmacy, University of Eastern Finland, Kuopio, Finland; Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Forensic Psychiatry, Niuvanniemi Hospital, University of Eastern Finland, Kuopio.
authors: Heidi
authors: H
authors: Taipale
authors: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Forensic Psychiatry, Niuvanniemi Hospital, University of Eastern Finland, Kuopio; National Institute for Health and Welfare, Helsinki.
authors: Antti
authors: A
authors: Tanskanen
authors: Kuopio Research Centre of Geriatric Care, University of Eastern Finland; School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
authors: Marjaana
authors: M
authors: Koponen
authors: School of Pharmacy, University of Eastern Finland, Kuopio, Finland; Research Centre for Comparative Effectiveness and Patient Safety (RECEPS), University of Eastern Finland.
authors: Anna-Maija
authors: AM
authors: Tolppanen
authors: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Forensic Psychiatry, Niuvanniemi Hospital, University of Eastern Finland, Kuopio.
authors: Jari
authors: J
authors: Tiihonen
authors: Kuopio Research Centre of Geriatric Care, University of Eastern Finland; School of Pharmacy, University of Eastern Finland, Kuopio, Finland; Department of Psychiatry, Kuopio University Hospital, Kuopio, Finland.
authors: Sirpa
authors: S
authors: Hartikainen
keywords: Prescription register; drug utilization; pharmacoepidemiology; validation studies