title: Congenital heart surgery: applicability of hospital reimbursement according to German diagnosis-related groups system in conformity with the Aristotle complexity score.
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.
authors.affiliation: Congenital Cardiac Centre, Deutsches Kinderherzzentrum, Sankt Augustin, Germany. n.sinzobahamvya@asklepios.com
authors.forename: N
authors.initials: N
authors.lastname: Sinzobahamvya
authors.forename: J
authors.initials: J
authors.lastname: Photiadis
authors.forename: C
authors.initials: C
authors.lastname: Arenz
authors.forename: T
authors.initials: T
authors.lastname: Kopp
authors.forename: H C
authors.initials: HC
authors.lastname: Blaschczok
authors.forename: V
authors.initials: V
authors.lastname: Hraska
authors.forename: B
authors.initials: B
authors.lastname: Asfour
mesh_terms: D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000191:economics* / Q000401:mortality; D005858:Germany; D006330:Heart Defects, Congenital / Q000191:economics* / Q000401:mortality / Q000601:surgery*; D017721:Hospital Costs; D017052:Hospital Mortality; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007297:Inpatients; D007349:Insurance, Health, Reimbursement / Q000191:economics*; D007902:Length of Stay / Q000191:economics; D018803:Models, Economic; D012121:Respiration, Artificial / Q000191:economics; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome