Evaluation of casemix-based funding in radiation oncology. German experience with disease-related groups for inpatient funding in radiation oncology

Purpose: In Germany a new casemix-related reimbursement system with "diagnosis related groups" (DRGs) for inpatient treatment was started in 2003. The first German system G-DRG 1.0 was developed on the basis of the Australian AR-DRG version 4.1. German inpatient treatment in radiation oncology was not specifically represented in this system due to the very different health care systems. As the DRG system was planned as a pricing system with severe effects on the funding of radiation oncology departments, an adjustment was urgently needed. For the modification, national data about pattern of care and economic relevance were needed. Methods: For 3,689 cases treated in radiation oncology departments from eleven hospitals data were collected prospectively concerning diagnosis, Length of stay, procedures and high-cost drugs and treatments. The DRGs were analyzed for homogeneity in Length of stay and costs. Readmission frequency and interval were analyzed and the relevance of existing reimbursement regulations for this situation was evaluated. Results: It could be shown, that radiation therapy implicated additional expenses for oncologic inpatients. These additional costs were not represented in the G-DRG 1.0 reimbursement system. Chemotherapy was an additional cause for economically inhomogeneous oncologic DRGs. The complex sequence of cases for the same patient could be shown, and that the rules for reimbursement of readmissions have to take these sequential treatments into account. Based on these data, modifications of the reimbursement system were suggested. In the following G-DRG version for the year 2004, 21 DRGs were designed for patients receiving radiation therapy. The regulations concerning the readmission of oncologic patients were modified. The correlation between the number of radiation therapy fractions and the total expense was acknowledged in the following year (G-DRG system 2005) and resulted in 35 DRGs. The version for 2006 showed the solidity of these solutions with almost unchanged definitions of these DRGs. Conclusion: This evaluation reveated the deficits in the G-DRG system 1.0 (and the AR-DRG system 4.1) related to the inpatient treatment in radiation oncology departments. Modifications could be proposed for following years. In 2004-2006, the regulatory boards adopted several implications of these data for the improvement of the German casemix-based hospital-financing system.