gms | German Medical Science

15th Annual Meeting of the German Drug Utilisation Research Group (GAA)

Gesellschaft für Arzneimittelforschung und Arzneimittelepidemiologie

20.11. - 21.11.2008, Bonn

Do defined daily doses (DDDs) reflect prescribing behaviour? A 3-month-analysis of data from a statutory health insurance company

Bilden Definierte Tagesdosen (DDDs) die Verordnungsrealität ab? Analyse von Krankenkassendaten

Meeting Abstract

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  • corresponding author Thomas Grimmsmann - Medical Review Board of the Statutory Health Insurance Funds Mecklenburg-Vorpommern, Schwerin, Germany
  • Wolfgang Himmel - Dept. of General Practice / Family Medicine, University of Göttingen, Germany

Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie e.V. (GAA). 15. Jahrestagung der Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie. Bonn, 20.-21.11.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. Doc08gaa02

The electronic version of this article is the complete one and can be found online at:

Published: November 6, 2008

© 2008 Grimmsmann 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: Although developed to study trends in drug consumption, the system of defined daily doses (DDDs), together with the ATC-system, is often used to compare costs between different treatments strategies or sometimes even to estimate the degree of the patients’ drug adherence. However, in order to use the DDD system as a powerful pharmacoepidemiological tool, it is essential that doctors prescribe 1 DDD per day for 1 patient, at least on average. The aim of this study was to explore to what degree doctors prescribe according to the ATC/DDD system.

Material and method: The database consisted of drug prescriptions for patients from a large statutory health insurance company. We analysed continuous prescriptions issued in primary care practices during the first 3 months of 2007 (n = 200,814 patients). The effectively prescribed daily doses for widely-used antihypertensive and anti-diabetic drugs were compared with the DDD.

Results: Selective beta blocking agents (ATC-Code C07AB) were prescribed with an average DDD of 0.9 (range for the different drugs within this group: 0.8 to 1.2). In contrast, the DDDs for all plain ACE-inhibitors (C09AA) were much higher (2.3), with a rather low DDD for Captopril (1.5) and the highest for Ramipril (3.5). Most patients (> 80%) received 2 or 4 DDDs of Ramipril; only 15% received 1 DDD. Similar effects could also be observed for anti-diabetic sulfonamides (A10BB) with a DDD of 1.0 for Glibenclamide and 2.0 for Glimepiride.

Conclusion: Depending on the drug group, the prescribed daily doses differed considerably from the DDD. This is even true for active substances of the same drug group. And even for a single drug, the DDDs differed considerably among individuals. As a result, comparisons of treatment costs as well as estimates of drug adherence on the basis of DDDs should be considered with caution.