Abstract:
Base-DRGs, Fractionation Coefficient, and Treemaps
for the Assessment of the
Relative Clinical Homogeneity of DRG Systems

Abstract (English)

This study complements the customary statistical homogeneity analyses (i. e. the computations of the achievable variance reduction and the remaining dispersion within DRGs) by means of a comparison of DRG systems on the level of base DRGs.

The study is based on 900,000 records from Swiss hospitals from the years 2000 to 2003. The records were selected according to quality criteria.

Pair comparisons were conducted to try to compute the divergence in the assignment of base DRGs of the AP-DRG, APR-DRG, AR-DRG, IR-DRG systems among each other, and for individual evaluations also according to SQLape, LDF and CCS, and to represent the results graphically. For this purpose, a so-called "fractionation coefficient" was developed. Visualisation was effected on the basis of treemaps.

The study yielded the following results: the actual DRG systems (AP, APR, AR, IR) partially display similar grouping concepts in the medical sphere. In this respect, the greatest similarities exist between AP and APR, and between IR and APR. In the surgical sphere, AP and, to a lesser extent, AR were found to have some common features with APR; apart from this, it became apparent that the surgical base DRGs are more diverse in their make-up than medical base DRGs. The most conspicuous differences were discovered between the surgical base IR DRGs and the surgical base DRGs of the other DRG systems.

In order to be able to compare the SQLape categories with the base DRGs in spite of the differing construction approach, the SQLape code of the main treatment was established for each individual hospital case. In addition, some analyses were also conducted with the help of the primary SQLape codes computed by the manufacturer. Correspondence with the other systems was relatively low. However, the different perspective also can serve to detect deficiencies in the DRG systems.

In comparison with the CCS classification, which is also based on a diverging concept, all the systems showed great differences, with the surgical SQLape main treatment categories being the exception.

The definitions of a great number of base DRGs are distinctly different in the systems under scrutiny. With regard to the choice of a DRG system, this means that it is not merely a licenser and a cooperation model that are chosen, but at the same time also a certain way of viewing clinical treatment.