A Comparative Study between New Injury Severity Score (NISS) and Injury Severity Score (ISS) to Predict the Outcome in Polytrauma Patients

Introduction: Polytrauma is a major cause of morbidity and mortality worldwide. The ISS and New Injury Severity Score are most commonly used to assess the gravity of trauma and serve in the estimation of outcomes. This study tries to compare the predictive validity of the NISS to the ISS among polytraumatized patients regarding mortality, admission to the ICU, and duration of hospitalization. Methods: It is a prospective observational study done in the Department of General Surgery, Dr. B.R.A.M. Hospital, Pt. J.N.M. Medical College, Raipur, from January 2022 to December 2022. We found 155 polytrauma cases in our series. In each case, ISS and NISS were calculated on the basis of their injuries. Predictive outcomes like mortality, need for ICU care, and length of hospital stay were analyzed. The scoring systems were compared using ROC curve analysis, logistic regression, and Pearson’s correlation coefficient. Results: The study showed that the mean ISS score for survivors was 16.22 ± 5.63, while the mean ISS for nonsurvivors was 34.86 ± 7.54. In the same vein, the mean NISS for survivors was 22.61 ± 8.67, and that of nonsurvivors was 43.51 ± 9.62. The AUC of the ROC curve for mortality prediction in relation to ISS was 0.825, while that for NISS was 0.904, showing that there is a statistically significant difference between them, as shown by p < 0.05. NISS was found to have better predictive value than ISS as regard to mortality, need for ICU admission, and length of hospital stay. The Pearson’s correlation coefficient of ISS and NISS scores was 0.826 and reached statistical significance at p < 0.001, indicating a strong positive correlation. Conclusion: ISS and NISS are helpful scoring systems in outcome prediction in polytrauma patients. However, the predictive performance enhanced significantly with the advantage of NISS regarding mortality and admission to intensive care. Moreover, it can also be a marker for the severity of trauma more reliably than any score; thus, its use in clinical practice should be put into practice to make any progress in the management of polytrauma patients.