gms | German Medical Science

16th Annual Meeting of the German Drug Utilisation Research Group (GAA)

Gesellschaft für Arzneimittelforschung und Arzneimittelepidemiologie

19.11. - 20.11.2009, Berlin

Studying the impact of policy interventions with medication claims data: the case of rebate contracts and 'aut idem'

Meeting Abstract

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  • corresponding author F. Hoffmann - Universität Bremen ZeS, Abteilung Gesundheitsökonomie, Gesundheitspolitik und Versorgungsforschung, Bremen, Germany
  • G. Glaeske - Universität Bremen ZeS, Abteilung Gesundheitsökonomie, Gesundheitspolitik und Versorgungsforschung, Bremen, Germany

Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie e.V. (GAA). 16. Jahrestagung der Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie. Berlin, 19.-20.11.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09gaa03

doi: 10.3205/09gaa03, urn:nbn:de:0183-09gaa031

Published: November 5, 2009

© 2009 Hoffmann et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Background and aim: Since April 1st, 2007 pharmacies are obligated to substitute medications within the statutory health insurance system preferably to products for which rebate contracts were made. Physicians are able to exclude such a substitution when crossing ‚aut idem’. This regulation existed already since 2002. We aimed to investigate if the use of ‚aut idem’ has changed after the introduction of rebate contracts.

Material and method: We used claims data of the Gmünder ErsatzKasse (GEK) and drew 3 independent random samples of 0.5% of the insured adult population in October 2006, 2007 and 2008 (n=6,195; n=6,300; n=6,845). After that, all relevant original prescriptions were screened.

Results: Between October in 2006, 2007 and 2008, we observed an increase of prescriptions in which ‚aut idem’ was used (14.4%; 18.4%; 19.0%; p for trend<0.0001). We found considerable differences between the local regional associations of statutory health insurance physicians. In about a quarter of all prescriptions of October 2007 and 2008 (25.1% resp. 25.7%) in which substitution was excluded, a medication included in a rebate agreement was prescribed.

Conclusions: This study gives insight into the use of ‚aut idem’ before and after the introduction of rebate contracts to the statutory health insurance system. Generally, evaluation of the impact of health policy interventions are clearly needed in Germany. Analysis using claims data can provide useful information for an evidence-based debate on the (positive and negative) impacts of policy interventions.