Predicting mortality in trauma patients-A retrospective comparison of the performance of six scoring systems applied to polytrauma patients from the emergency centre of a South African central hospital

Introduction: Over 90% of trauma-related deaths worldwide, ensue in low- and middle-income countries. Multiple useful trauma scoring systems have been devised. Although validated in high-income countries, they cannot always be replicated in resource-limited countries. This study compares six trauma scores to identify the bestsuited system to use for polytrauma patients in a hospital in Pretoria, South Africa. Methods: This is an observational retrospective analysis of polytrauma admissions from 1 July 2016 to 31 December 2016. Data collected from patients' records from the EC of Steve Biko Academic Hospital, was analysed using Stata Release 14. Outcomes were recorded as 30-day survival, ICU- and overall hospital LOS. Scores pertaining to patient mortality, were compared in terms of sensitivity, specificity, and cut-off points based on ROC curve. Finally, for LOS Pearson correlation analysis was used. Results: At the best calculated mortality prediction cut-points for the scores, the sensitivities and specificities were respectively 87% and 68% for TRISS, 81% and 61% for ISS, RTS yielded 81% and 60%, while for REMS it was 61% and 69%. The SI and RSI (cut-points used in agreement with the literature) produced sensitivities 58% and only 48%, and specificities of 73% and 83%, respectively. 45(41,7%) patients required ICU admission. Though the ICU LOS best correlated with ISS(r = 0.2710), the ICU LOS correlation coefficient was weak for all trauma scores. None of the scores had a significant p value for hospital LOS. Discussion: Among the scores compared, TRISS had the highest sensitivity and NPV for mortality prediction in this South African polytrauma population. ISS correlated best with ICU LOS. However, compared to developed countries, ROC analyses & predictability of these scores fare relatively worse, and no correlation was found with hospital LOS. Therefore, we conclude that further studies are needed to ascertain a more suitable system for resource-limited settings.