title: [Regional differences in the use of 'no substitution' in the elderly after introduction of rebate contracts].
abstract: OBJECTIVE
  As of 1 April 2007, pharmacists in Germany filling prescriptions covered by the statutory health insurance system (Gesetzliche Krankenversicherung, GKV) are required, whenever possible, to dispense a preparation for which a rebate contract is in effect. The physician can block drug substitution by crossing out 'aut idem' ('or the like') on the prescription form, for which regional variations were found. We have studied the differences between physicians belonging to different regional Associations of Statutory Health Insurance Physicians (Kassenärztliche Vereinigungen, KVs) in the use of the no-substitution option in the elderly.
  
  
  METHODS
  We used claims data of the Gmünder ErsatzKasse (GEK) and drew a random sample stratified according to the 17 KVs and 3 age groups (65-74; 75-84; 85+ years) of at least 75 continuously insured persons in October 2008 per stratum. After that, all prescriptions in which the physician could potentially have exercised a no-substitution option were selected and all relevant original prescriptions were examined. All estimates were weighted according to KVs, age groups and sex as of the structure of the GKV.
  
  
  RESULTS
  The sample comprised of 3 672 persons and 5 745 prescriptions. The percentage of no-substitution prescriptions was 20.1% (95% confidence interval [95% CI] 18.7-21.5) and we found no differences according to age and sex. Considerable differences were seen between the KVs that vary 6.8-fold between 6.2% (95% CI: 3.2-9.2) in Saarland and 42.2% (95% CI: 34.1-50.4) in Saxony.
  
  
  CONCLUSIONS
  The use of the no-substitution option does not depend on age and sex of the patient but rather depends on regional factors. These considerable regional differences show that, in several regions, the use of the no-substitution regulation influences the effect of rebate contracts.
authors.affiliation: Universität Bremen, ZeS, Abteilung Gesundheitsökonomie, Gesundheitspolitik und Versorgungsforschung, Ausser der Schleifmühle 35– 37, Bremen. hoffmann@zes.uni-bremen.de
authors.forename: F
authors.initials: F
authors.lastname: Hoffmann
authors.forename: R
authors.initials: R
authors.lastname: Windt
authors.forename: G
authors.initials: G
authors.lastname: Glaeske
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003284:Contract Services / Q000331:legislation & jurisprudence; D032982:Contracts / Q000331:legislation & jurisprudence*; D057915:Drug Substitution; D005260:Female; D005858:Germany; D006302:Health Services Research; D006299:Health Services for the Aged / Q000331:legislation & jurisprudence*; D006801:Humans; D007345:Insurance Claim Review; D008297:Male; D009313:National Health Programs / Q000331:legislation & jurisprudence*; D010818:Practice Patterns, Physicians' / Q000331:legislation & jurisprudence*; D012737:Sex Factors