Evaluation of the APACHE II as a mortality scoring system among intensive care unit polytrauma patients at a tertiary hospital in South Africa

Background Trauma is the third largest contributor to the global burden of disease with 90% of the trauma-related mortality occurring in low to middle income countries (LMICs) such as South Africa. The Acute Physiology and Chronic Health Evaluation (APACHE) II is widely used, but was developed in a first-world setting. This study sought to evaluate the APACHE II's ability to predict intensive care unit (ICU) mortality among trauma patients in a LMIC and to identify predictors of mortality within this population. Methods This retrospective study was conducted by analysing data records of 284 ICU patients over 2 years. Performance of the APACHE II was assessed with calibration and receiver operator characteristic curves. Survivors and non-survivors were compared using descriptive statistics, and logistic regression identified independent risk factors. Results An overall mortality rate of 18.8% was observed. Sensitivity of the APACHE II was 0.74, and specificity 0.68. The model showed good discrimination (area under receiver operating curve (AUROC) 0.82, 95% confidence interval) and calibration (Hosmer–Lemeshow p > 0.3). The cut-off value for APACHE II was 20.2. Community assault and intubation were more common in the demised cohort (p < 0.01, odds ratio (OR) 4) although the APACHE II remained the strongest predictor of mortality when adjusting for confounders (p < 0.001). Conclusion APACHE II is a valid mortality prediction tool in polytrauma patients. Patients with scores above 20 were at highest risk of mortality. Intubation and community assault were significant risk factors of mortality, however, they aren’t included in the APACHE II score, highlighting the need to consider additional risk factors in the trauma population.