[Regional differences in the use of 'no substitution' in the elderly after introduction of rebate contracts]. / Regionale Unterschiede in der Nutzung des Aut-idem-Verbots bei Älteren nach Einführung der Rabattverträge.

ABSTRACT

AIM: 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. CONCLUSION: 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.