[Case allocation of extensive operations on head and neck within the German DRG system 2004-2007: what is the net result of the continued developments in case allocation?].

Background: When the German DRG system was implemented there was some doubt about whether patients with extensive head and neck surgery would be properly accounted for. Significant efforts have therefore been invested in analysis and case allocation of those in this group. The object of this study was to investigate whether the changes within the German DRG system have led to improved case allocation.
Methods: Cost data received from 25 ENT departments on 518 prospective documented cases of extensive head and neck surgery were compared with data from the German institute dealing with remuneration in hospitals (InEK). Statistical measures used by InEK were used to analyse the quality of the overall system and the homogeneity of the individual case groups.
Results: The reduction of variance of inlier costs improved by about 107.3% from the 2004 version to the 2007 version of the German DRG system. The average coefficient of cost homogeneity rose by about 9.7% in the same period. Case mix index and DRG revenues were redistributed from less extensive to the more complex operations. Hospitals with large numbers of extensive operations and university hospitals will gain most benefit from this development.
Conclusion: Appropriate case allocation of extensive operations on the head and neck has been improved by the continued development of the German DRG system culminating in the 2007 version. Further adjustments will be needed in the future.