Objective: To assess the relationship between diagnosis related groups (DRG) and severity of illness in intensive care unit (ICU) patients in semf1tical and economical terms.
Study design: Prospective, multicentric study including 13 medical and surgical ICUs for adults.
Material: Discharge reports of 3,215 ICU admissions including age, gender, diagnosis, organ system failures, length of stay (LOS) and severity of illness evaluated with severity scores (SS): simplified acute physiological score (SAPS). Apache II, Glasgow score and physiological score (PS).
Methods: Semantical homogeneity was evaluated from the percentage of well-classified patients established from the comparison between the official computerized method and a non-computerized method applied by three clinical experts. Economical homogeneity was evaluated from the relationship between SS and LOS.
Results: In total, 88% (CI: 87.7-88.2) of ICU stays were classified in eight main categories of diagnosis (MCD). According to the MCD, the percentage of well-classified patients varied from 28% (CI: 27.6-28.3) to 97% (CI: 96.8-97.1), decreasing with the association of several diagnoses and organ system failures. There was a large variability in the LOS of DRG and a significant correlation between LOS and SS was found in only 8/16 DRG.
Conclusion: The fact that the severity of illness is not taken into account in the elaboration of DRGs explains the inadequacy of the DRG system in intensive care.