The NACA score predicts mortality in polytrauma patients before hospital admission: A registry-based study.

Background: The early assessment of the severity of polytrauma patients is key for their optimal management. The aim of this study was to investigate the discriminative performance of the NACA score in a large dataset by stratifying the severity of polytraumatized patients in correlation to Injury Severity Score (ISS), Glasgow Coma Scale (GCS), and mortality. Methods: This study on the Swiss Trauma Registry investigated 2239 polytraumatized patient (54.3±22.8 years) enrolled from 2015 to 2023: 0.5% were NACA 3, 76.7% NACA 4, 21.4% NACA 5, and 1.4% NACA 6. The NACA predictive value of patients’ mortality was investigated, as well as the correlation of ISS and GCS scores, and other factors influencing patients’ survival at discharge and after 28 days. Results: In NACA 4 and 5 the survival rate during hospitalization was 97.7% and 82.5%, respectively, and 28-day mortality 3.5% and 23.5%, respectively (p<0.0005). NACA correlated with GCS in the prehospital phase and in the emergency room (p<0.0005), as well as with ISS (p<0.0005). NACA 4 and 5 presented different injury patterns (fall <3m vs vehicle accident) with NACA 5 requiring more CPR and intubation (p<0.001, p<0.0005). The ROC AUC analysis showed the prehospital NACA and GCS values as the strongest variables predicting patients’ survival. Conclusions: This study provides valuable evidence supporting the effectiveness of the NACA score in assessing the severity of polytrauma patients. The NACA is a valid score for assessing polytrauma, correlating with both the pre-ER as well as the ER condition, as well as the post-hospitalization ISS assessment of patient severity.