[Changes in the G-DRG System from 2003 to 2005 in Ophthalmology--Ophthalmologic G-DRG 2003 to 2005]

The objective of the study was to illustrate the effect of the extensive changes of the German DRG System on reimbursement of clinical ophthalmology during the years 2003, 2004 and 2005.

All ophthalmologic patients treated as in-patients at the Department of Ophthalmology at the University Munich during the year 2003 served as a reference data basis. By means of appropriate software those cases were then re-grouped according to the G-DRG classification of the years 2003, 2004 and 2005. This resulted in different reimbursements caused only by system changes for an exemplary hospital of maximum medical care. In addition, the same calculations were performed for four virtual, typical clinics based on the calculation data of the "Institut für Entgeltsysteme (InEK)". For those four clinics it was assumed that 80 % of the cases came from one of the subspecialties retina, glaucoma, cataract or strabismus surgery.

Changes in the G-DRG system caused the sample hospital of maximum care to loose 8.5 % case mix index (CMI) during the period of 2003 to 2005. For three of the four virtual, typical ophthalmological clinics the theoretic reimbursement conditions also deteriorated: retina surgery -- 10.6 %, glaucoma surgery - 15.8 % and cataract surgery -- 17.9 % CMI. Only strabismus surgery showed an increase of + 5.6 % in CMI during the period examined.

Over the years 2003 to 2005 the CMI clearly deteriorated for many ophthalmological subspecialties given otherwise identical conditions. To calculate the changes specifically for an individual hospital, the individual base rates have to be considered.