Early warning scores and peripheral perfusion index: A Comparative assessment for 30-day mortality in critical patients in emergency departments

Early identification of high-risk patients in emergency departments (EDs) is crucial. This study compares the prognostic value of the National Early Warning Score-2 (NEWS-2), Modified Early Warning Score (MEWS), and Peripheral Perfusion Index (PPI). To compare the performance of NEWS-2, MEWS, and PPI in predicting 30-day mortality among critically ill patients admitted to the intensive care unit. A prospective, observational study (June–October 2024) included 306 critically ill patients. NEWS-2, MEWS, and PPI were recorded upon presentation. The primary outcome was 30-day mortality. ROC analysis was used to determine the area under the curve (AUC), sensitivity, and specificity. The 30-day mortality rate was 29.7% (n = 91). Significant differences were found in all scores between survivors and non-survivors (p < .001). NEWS-2 demonstrated the highest discrimination (AUC 0.666; 95% CI 0.598–0.733), followed by MEWS (AUC 0.643) and PPI (AUC 0.633). While NEWS-2 (cutoff ≥ 6) provided the highest sensitivity at 71.4%, the PPI (cutoff ≤ 1.15) exhibited the highest specificity at 78.6%. NEWS-2 remains the strongest single predictor for 30-day mortality. However, the PPI offers high specificity and reflects microcirculatory impairment, making it a valuable complementary tool alongside established early warning scores rather than a replacement.