Evaluation and comparison of the three scoring systems at 24 and 48 h of admission for prediction of mortality in an Indian ICU: a prospective cohort study

IntroductionPredictive accuracy of severity scoring systems in Indian ICUs does not fit well owing to differences in case mix from the west. We hypothesized that 24 h is too early to predict the outcome and that the predictive accuracy of these scores might be better at 48 h of ICU admission.ObjectiveThe aim of this study was to evaluate and compare Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology (SAPS) II, and Sequential Organ Failure Assessment (SOFA) as a predictor of outcome in critically ill patients at 24 and at 48 h in a tertiary care hospital ICU.Patients and methodsA prospective cohort study was conducted on 169 patients over 2 years at a single medical surgical ICU. Eighty-five critically ill patients were included. For each patient, APACHE II, SAPS II, and SOFA scores were calculated at two time frames (first at 24 and then at 48 h) after ICU admission. The accuracies and comparisons of outcome prediction by the three scores were assessed with standardized mortality ratio and area under the receiver operating characteristic (AUROC) curves.ResultsAll scoring systems (except SOFA) underestimated the deaths (standardized mortality ratio>1). All scoring systems displayed larger AUROC curves at 48 h than those at 24 h. APACHE II 48 showed the largest AUROC of 0.933.ConclusionAll scores performed better when calculated at 48 h rather than at 24 h. Overall, APACHE II 48 is the best predictor of 28-day mortality in critically ill patients. A worsening APACHE II score at 48 h after ICU admission may identify the patients at high risk of mortality.