Using ICD-10 for case groups.
The definition of German case groups now uses an adaptation of the ICD-10: ICD-10-SGBV. For the transformation of the existing ICD-9-based definition into the ICD-10-SGBV an ICD-9/ICD-10 conversion table was used. The derived raw definitions were manually refined in detail. Due to the transformation of the classification system, the number of definitions increased immensely, as the ICD-10 SGBV is by far more detailed than the formerly used ICD-9. In our opinion, ICD-10 SGBV is not ideal for the definition of case groups, because this classification system is designed to support statistics on morbidity and mortality, but definitions of case groups are oriented to cost factors. Therefore the definition of case groups should be based on a specially designed classification system or one should reassess the necessity of a parallel definition by codes of classifications as well as by text. In both alternatives the introduction of a detailed and systematic medical documentation with expressive terminology systems will offer the advantage of classifying patients into medical oriented classifications as well as case groups.