Comparative Analysis of APACHE IV Score Variables in Predicting the Outcome of Critically ill Patients: Identifying Key Components for Mortality Prediction in Low-resource Settings

Background: The APACHE IV score is a widely used tool for predicting outcomes in critically ill patients. However, in resource-limited settings, complete data required for its calculation may not be readily available, and manual computation without automated systems can be resource-intensive. This study aimed to identify key APACHE IV variables that reliably predict mortality. Methods: In this prospective cohort study, 150 critically ill patients admitted to a multidisciplinary ICU were categorised into survivor and non-survivor groups based on ICU and hospital outcomes. Clinical and laboratory variables used to calculate APACHE IV score were recorded during the first 24 hours of admission, and the worst values were analysed. Comparisons were performed using independent sample t -tests and chi-square tests, with P < .05 considered significant. Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive performance of the APACHE IV score and selected variables. Results: Significant predictors of ICU mortality included lower mean arterial pressure (62.6 vs. 81.8 mm Hg, P = .002), lower systolic BP (110.7 vs. 128.2 mm Hg, P = .008), and reduced GCS score (4.7 vs. 11.7, P < .001). Non-survivors had elevated urea levels (96.1 vs. 58.5 mg/dL, P = .026), high bilirubin (1.9 vs. 0.8 mg/dL, P < .001), low albumin (2.9 vs. 3.6 g/dL, P = .001) and low platelet counts (154,328/mm³ vs. 245,977/mm³, P = .008). Hospital mortality showed similar patterns, with non-survivors demonstrating lower GCS, increased FiO 2 requirements (44.1% vs. 33.1%, P = .010), elevated urea, lower albumin and reduced platelet counts. The need for mechanical ventilation was more common among both the ICU and hospital non-survivors. ROC analysis demonstrated excellent predictive ability of the APACHE IV score for ICU mortality (AUROC: 0.863) and good performance for hospital mortality (AUROC: 0.760). GCS and albumin also showed good discrimination for ICU mortality and acceptable discrimination for hospital mortality. Conclusion: Lower MAP, SBP, and GCS, along with reduced platelet count and albumin levels, and elevated urea and bilirubin levels, as well as the need for mechanical ventilation, are key predictors of ICU and hospital mortality. The APACHE IV score demonstrates excellent predictive performance for mortality. Selected variables, particularly GCS and serum albumin, also show good discriminatory power and may serve as practical tools for mortality prediction in resource-limited settings.