COMPARISON OF APACHE II & IV SCORING SYSTEM IN PREDICTING THE OUTCOME OF PATIENT ADMITTED IN CRITICAL CARE UNIT

Background: Prognostication of critically ill patients in the Intensive Care Unit (ICU) is vital for highquality care. Severity of illness scoring systems, such as APACHE II and APACHE IV, have been developed to enhance objectivity in predicting outcomes. This study aimed to evaluate the performance of APACHE II and APACHE IV in predicting mortality risk among critically ill Indian patients with respiratory issues. Methods: A prospective observational study was conducted in a multidisciplinary ICU, including 100 adult patients. Data were collected on demographics, comorbidities, and clinical parameters. APACHE II and APACHE IV scores were calculated within the rst 24 hours of admission. Discrimination and calibration of the scoring systems were assessed using area under the receiver operating characteristic curve (AUC) and the Hosmer-Lemeshow goodness-of-t test, respectively. Results: The mean APACHE II score was 19.5 ± 8.3, and the mean APACHE IV score was 59.2 ± 27.1. The study population had a crude hospital mortality rate of 17%. Both scoring systems were signicantly higher in non-survivors. The correlation between APACHE II and APACHE IV scores was strong (Spearman's rho = 0.802, P < 0.001). APACHE IV demonstrated better discrimination (AUC = 0.81) compared to APACHE II (AUC = 0.74). However, both models showed poor calibration, with APACHE II exhibiting better calibration than APACHE IV. Conclusion: Both APACHE II and APACHE IV are reasonably effective in discriminating between outcomes in our ICU but show poor calibration. Larger multicenter validation studies tailored to the Indian context are needed for effective application.