[Cost analysis as a tool for assessing the efficacy of intensive care units].

Background: The German "Hospital Structure Act" intends to align the state hospital planning on quality criteria. Within this process cost-utility analyses (CUAs) shall be used to assess the efficacy of medical care. To be objective, CUAs of intensive care units (ICUs) require standardization (adjustment) of costs. The present study analyzed the extent to which treatment costs are related to patient-specific baseline variables (such as type and severity of the primary disease).

Methods: From 2000-2004, a bottom-up procedure was used to quantify total costs on 14 ICUs in nine German university hospitals. Results were combined with demographic data, and data indicating type (ICD-10 codes) and severity (ICU scoring systems) of the primary disease at ICU admission. Various statistical models were tested to identify that which best described the associations between baseline variables and costs.

Results: In all, 3803 critically ill patients could be examined. The median of treatment costs per patient was 3199 € (IQR 1768-6659 €). No model allowed an acceptably precise adjustment of costs; the estimated mean absolute prognostic error was at least 3860 € (mean relative prognostic error 66%), when we tested an Extreme Gradient Boosting Model.

Conclusion: Instruments which are currently available (cost adjustment based on patient-specific baseline variables) do not allow a standardization of costs, and an objective CUA of ICUs. Factors unknown at baseline may cause a large portion of treatment costs.