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

How are asthma types coded in the out-patient sector? Analysis of claims data from 2004–2007

Meeting Abstract

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  • corresponding author Roland Windt - Universität Bremen, ZeS, Abteilung Gesundheitsökonomie, Gesundheitspolitik und Versorgungsforschung, Bremen, Germany
  • Gerd 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. Doc09gaa18

doi: 10.3205/09gaa18, urn:nbn:de:0183-09gaa184

Published: November 5, 2009

© 2009 Windt 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: Aim of the study is to assess physicians coding of Asthma in the out-patient sector using health insurance claims data. We conducted the study with focus on the four-character ICD10 code to find out how often different asthma types were diagnosed.

Material and method: Out-patient claims data of the Gmünder ErsatzKasse (GEK) between 2004 and 2007 were used. Persons classified as having asthma were included (at least 3 quarters per year with ambulatory documentations of asthma diagnosis). During physician-related assessment one diagnosis coding was counted once per patient and quarter.

Results: The most frequently coded asthma type in 2007 was "asthma, unspecified" (ICD10:J45.9; 1.28% of all insured persons). Allergic asthma (ICD10:J45.0; 0.62%) was the second most frequent type. The diagnoses nonallergic asthma (ICD10:J45.1; 0.12%) and mixed asthma (ICD10:J45.8; 0.10%) are coded to a much lesser extent. In young persons the proportion of persons with allergic asthma is higher, whereas the nonallergic type is slightly more frequent in the elderly. No noticeable change over time was observed when comparing results from year 2007 with those of 2004–2006.

In 64.4% (2007) of the cases physicians coded asthma unspecifically (J45.9), with paediatricians (68.9%) and GPs (69.6%) above average. Physicians specialized in dermatology/allergology (J45.9: 45.6%) and internal medicine/pneumology (J45.9: 50.1%) differentiated types most frequently.

Conclusions: The predominantly ICD10-coded asthma type in all age groups is "Asthma, unspecified". Due to this result, it is not possible to assess the frequencies of different asthma types more comprehensively. Claims data are collected for administrative rather than for research purposes. Though asthma is in the disease pool of "Morbi-RSA", no change is expected, because a more precise asthma categorization is not relevant for administrative purposes. We identified noticeable differences in coding behaviour of various specialist groups, with a stronger subcategory differentiation on the part of allergologists and internists/pneumologists, respectively.