Characteristics and Outcomes of Critically Ill Trauma Patients in Australia and New Zealand (2005-2017)

Objectives: To compare the characteristics of adults admitted to the ICU in Australia and New Zealand after trauma with nonelective, nontrauma admissions. To describe trends in hospital mortality and rates of discharge home among these two groups. Design: Retrospective review (2005-2017) of the Australia and New Zealand Intensive Care Society's Center for Outcome and Resource Evaluation Adult Patient Database. Setting: Adult ICUs in Australia and New Zealand. Patients: Adult (≥17 yr), nonelective, ICU admissions. Intervention: Observational study. Measurements and Main Results: We compared 77,002 trauma with 741,829 nonelective, nontrauma patients. Trauma patients were younger (49.0 ± 21.6 vs 60.6 ± 18.7 yr; p < 0.0001), predominantly male (73.1% vs 53.9%; p < 0.0001), and more frequently treated in tertiary hospitals (74.7% vs 45.8%; p < 0.0001). The mean age of trauma patients increased over time but was virtually static for nonelective, nontrauma patients (0.72 ± 0.02 yr/yr vs 0.03 ± 0.01 yr/yr; p < 0.0001). Illness severity increased for trauma but fell for nonelective, nontrauma patients (mean Australia and New Zealand risk of death: 0.10% ± 0.02%/yr vs -0.21% ± 0.01%/yr; p < 0.0001). Trauma patients had a lower hospital mortality than nonelective, nontrauma patients (10.0% vs 15.8%; p < 0.0001). Both groups showed an annual decline in the illness severity adjusted odds ratio (odds ratio) of hospital mortality, but this was slower among trauma patients (trauma: odds ratio 0.976/yr [0.968-0.984/yr; p < 0.0001]; nonelective, nontrauma: odds ratio 0.957/yr [0.955-0.959/yr; p < 0.0001]; interaction p < 0.0001). Trauma patients had lower rates of discharge home than nonelective, nontrauma patients (56.7% vs 64.6%; p < 0.0001). There was an annual decline in illness severity adjusted odds ratio of discharge home among trauma patients, whereas nonelective, nontrauma patients displayed an annual increase (trauma: odds ratio 0.986/yr [0.981-0.990/yr; p < 0.0001]; nonelective, nontrauma: odds ratio 1.014/yr [1.012-1.016/yr; p < 0.0001]; interaction: p < 0.0001). Conclusions: The age and illness severity of adult ICU trauma patients in Australia and New Zealand has increased over time. Hospital mortality is lower for trauma than other nonelective ICU patients but has fallen more slowly. Trauma patients have become less likely to be discharged home than other nonelective ICU patients.