Using population-based critical care data to evaluate trauma outcomes

Background: The analysis of mortality is an integral part of the evaluation of trauma care. When specific data are not available, general prediction models can be used to adjust for case mix. The aim of this study was to evaluate the feasibility of conducting a population-based analysis of trends in trauma mortality, using critical care audit data, and to investigate whether such data could provide a benchmark for the assessment of service reconfiguration. Methods: Retrospective cohort study of adult trauma patients, requiring admission to a critical care unit in Scotland, 2002-2011, using nationally collected data. Results are presented as standardised mortality ratios of observed mortality divided by APACHE II predicted mortality. Tests for trends in numbers and ratios over time were performed using linear regression. Findings: 4503 patients were identified. There was a significant increase in the number of trauma patients admitted per year (p = 0.011). The median predicted probability of in-hospital death was 7% (interquartile range 1-13%), against an actual mortality was 11.6%. There was no significant change in the standardised mortality ratios of trauma patients (p = 0.1224). Conclusions: This study demonstrated the feasibility of utilising critical care unit audit data for analysing outcomes from trauma care. It also showed the potential of such an approach to establish a baseline against which to compare the impact of future service reconfiguration. In contrast to healthcare systems with regionalised trauma care, there appears to have been little change in the mortality of trauma patients requiring critical care unit admission in Scotland.