Prediction of mortality in critically-ill elderly trauma patients: a single centre retrospective observational study and comparison of the performance of trauma scores

BACKGROUND: Trauma in the elderly (≥ 65 years) population is increasing. This study compares the performance of trauma scoring systems in predicting 30-day mortality among the traumatised elderly patients admitted to the intensive care unit in a major trauma centre. METHODS: We collected retrospective data for all elderly trauma patients admitted to our intensive care units between January 2012 and December 2017. We assessed Injury Severity Score (ISS), Geriatric Trauma Outcome Score (GTOS) and the Trauma Audit and Research Network’s (TARN) Probability of Survival (Ps17) between survivors and non-survivors. Receiver operator characteristic (ROC) curves were used to assess the performance of these scoring systems. RESULTS: There were 255 elderly trauma patients with overall 30-day survival of 76%. There was a statistically significant difference in ISS, GTOS and Ps17 scores between survivors and non-survivors (p < 0.001). The area under the ROC curve (AUROC) was statistically significant for all 3, with AUROC of 0.66 (95% CI 0.59–0.74) for the ISS, 0.68 (95% CI 0.61–0.76) for the GTOS and 0.79 (95% CI 0.72–0.85) for the Ps17. The optimal cut-off points were ≥ 28, ≥ 142, ≤ 76.73 for ISS, GTOS and Ps17, respectively. CONCLUSION: Both ISS and GTOS scoring systems preformed equally in predicting 30-day mortality in traumatised elderly patients admitted to the intensive care unit, however neither were robust enough to utilise in clinical practise. The Ps17 performed more robustly, although was not developed for prognosticating on individual patients. Larger prospective studies are needed to validate these scoring systems in critically-ill elderly traumatised patients, which may help to facilitate early prognostication.