Use of the APACHE II Score for the Assessment of Outcome and Mortality Prediction in an Iranian Medical-Surgical Intensive Care Unit

The Acute Physiology and Chronic Health Evaluation (APACHE) II is still commonly used as an index of illness severity in patients admitted to intensive care unit (ICU) and has been validated in many research and clinical audit purposes.The aim of this study is to investigate the diagnostic value of APACHE II score for predicting mortality rate of critically ill patients. This was a retrospective cross-sectional study of 200 patients admitted in the medical-surgical adult ICU. Demographic data, pre-existing comorbidities, and required variables for calculating APACHE II score were recorded. Receiver operating characteristic (ROC) curves were constructed and the area under the ROC curves was calculated to assess the predictive value of the APACHE II score of in-hospital mortality. Of the 200 patients with mean age of 55.27 ± 21.59 years enrolled in the study, 112 (54%) were admitted in the medical ICU, and 88 (46%) in the surgical ICU. Finally, 116 patients (58%) died and 84 patients (42%) survived. The overall actual and predicted hospital mortality were 58% and 25.16%, respectively. The mean APACHE II score was 16.31 in total patients, 17.78 in medical ICU, and 14.45 in surgical ICU, and the difference was statistically significant between the two groups (P= 0.003). Overall, the area under ROC curve was 0.88. APACHE II with a score of 15 gave the best diagnostic accuracy to predict mortality of patients with a sensitivity, specificity, positive and negative predictive values of 85.3%, 77.4%, 83.9%, and 73.9%, respectively. Despite significant progress has been made in recent decades in terms of technology and equipment, therapeutics and process of care and identifies in the ICU setting, these scientific efforts have not directly led to a further reduction in mortality for patients hospitalized in the ICU.