Descriptive patient data as an explanation for the variation in average daily costs in intensive care.

Intensive care patients require therapy that can vary considerably in type, duration and cost, so making it extremely difficult to predict patient resource use. Few studies measure actual costs; usually average daily costs are calculated and these do not reflect the variation in resource use between individual patients. The aim of this study was to analyse a data set of 193 critically ill adult patients to look for associations between routinely collected descriptive data and patient-specific costs. Regression analysis was used to explore any relationships between average daily patient-specific costs and the following variables: duration of intensive care unit stay, Acute Physiology and Chronic Health Evaluation II scores in the first 24 h, gender, age, mechanical ventilation at any point during the stay, postoperative status, emergency admission and mortality. Overall, this analysis explained 33.6% of the variation in average daily costs. The additional costs of an extra day of care, mechanical ventilation, an extra point on the Acute Physiology and Chronic Health Evaluation II score, and survival were obtained.