Evaluation of proposed casemix criteria as a basis for costing patients in the adult general intensive care unit.

This study analyses the relationship between the actual patient-related costs of care calculated for 145 patients admitted sequentially to an adult general intensive care unit and a number of factors obtained from a previously described consensus of opinion study. The factors identified in the study were suggested as potential descriptors for the casemix in an intensive care unit that could be used to predict the costs of care. Significant correlations between the costs of care and severity of illness, workload and length of stay were found but these failed to predict the costs of care with sufficient accuracy to be used in isolation to define isoresource groups in the intensive care unit. No associations between intensive care unit mortality, reason for admission and intensive and unit treatments and costs of care were found. Based on these results, it seems that casemix descriptors and isoresource groups for the intensive care unit that would allow costs to be predicted cannot be defined in terms of single factors.