Abstract
Background: Scores of Aristotle comprehensive complexity (ACC) levels have been demonstrated
to correlate with the case-mix index (CMI) (cost-weights) generated by the German
Diagnosis-Related Groups (DRG) 2009 version (G‐DRG 2009). The equation used was “y = 0.5591 + 0.939 x”
whereby y stands for cost-weight and x for ACC score. We hypothesised that each ACC
level could be assigned a DRG (ACC DRG) and be used to determine hospital reimbursement.
Methods: 185 patients underwent cardiac surgery between January and June 2009. The ACC scores
of these 185 patients were grouped in ACC levels, based on the basic cost-weight value
of their DRG. One ACC DRG was assigned to each group and a corresponding cost-weight
calculated based on the aforementioned equation. The resulting ACC CMI was compared
with the CMI generated by the G‐DRG 2009 (G‐DRG 2009 CMI). Finally, the ACC surgical
performance (complexity x hospital survival) was used to calculate the cost-weight;
the obtained CMI was called “effective ACC CMI”. Results: Mean ACC score was 9.515 ± 3.611 points. Derived ACC CMI and related G‐DRG 2009 CMI
were 9.494 and 8.438, respectively. Hospital survival was 97.8 % (181/184). Therefore
ACC surgical performance and “effective ACC CMI” were 9.306 and 9.297, respectively.
For each ACC level, the number of patients (n), mean ACC score, ACC CMI and related
G‐DRG 2009 CMI were as follows: Level 1: n = 25, 4.024 ± 0.879, 4.338 and 5.911; Level
2: n = 30, 6.563 ± 0.574, 6.722 and 6.602; Level 3: n = 43, 8.665 ± 0.540, 8.695 and
8.088; Level 4: n = 73, 11.730 ± 1.690, 11.574 and 9.612; Level 5: n = 14, 16.710 ± 1.380,
16.249 and 11.843, respectively. Conclusions: The Aristotle score can be used to adjust hospital reimbursement by assigning a DRG
and cost-weight value to each ACC level. Missing figures for level 6 can be obtained
from a previous study which showed a mean score of 22.11 ± 1.24: the ACC CMI would
be 21.320. The 6 ACC DRGs indicate the correct compensation based on the complexity
of the procedure. Reimbursement using the German DRG 2009 appears to favour less complex
cases, while procedures with a higher complexity are penalised. Reimbursement according
to “effective ACC CMIs” would have a strong impact by supporting units providing high-quality
care.
Key words
congenital heart disease - cost analysis - health economics - health provider payments
- Aristotle complexity score
References
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