Using the GAP score as a complement to the new injury severity score in identifying severely injured patients- A registry-based cohort study of adult trauma patients in Sweden.

ABSTRACT

BACKGROUND: New Injury Severity Score (NISS) and Glasgow Coma Scale, Age and Pressure (GAP) scoring systems have cutoffs to define severe injury and identify high-risk patients. This is important in trauma quality monitoring and improvement. The overall aim was to explore if GAP scoring system can be a complement or an alternative to the traditional NISS scoring system. METHODS: Adults exposed to trauma between 2017 and 2021 were included in the study, using data from The Swedish Trauma Registry. The performance of NISS and GAP scores in predicting mortality, and ICU admissions were assessed using the area under the receiver operator characteristics (AUROC) in all patients and in subgroups (blunt, penetrating trauma and older (≥65 years) trauma patients). Patients were classified as severely injured by NISS >15 as Severely Injured NISS (SIN) or with a high-risk for mortality, by GAP 3-18 as High Risk GAP (HRG). Undertriage was calculated based on the cutoffs HRG and SIN. RESULTS: Overall, 37,017 patients were included. The AUROC (95 % CI) for mortality using NISS was 0.84 (0.83-0.85) and for GAP 0.92 (0.91-0.93) (p-value <0.001), the AUROC (95 % CI) for ICU-admissions was 0.82 (0.82-0.83) using NISS and for GAP 0.70 (0.70-0.71) p-value <0.001, in the overall cohort. In older patients the AUROC (95 % CI) for mortality was 0.76 (0.75-0.78) using NISS and 0.79 (0.78-0.81) using GAP, p-value <0.001. Overall, 8,572 (23.2 %) and 2,908 (7.9 %) were classified as SIN and HRG, respectively, with mortality rates of 13.7 % and 34.3 %. In the HRG group low-energy falls dominated and in the SIN group most patients were exposed to MVCs. In the SIN and HRG groups the rate of Emergency Trauma Interventions according to Utstein guidelines (ETIU) and ICU admission was 14.0 vs 9.5 % and 47.0 vs 62.5 % respectively. CONCLUSION: Our findings suggest that the GAP score and its cutoff 3-18 can be used to define severe trauma as complement to NISS >15 and can be a valuable tool in trauma quality monitoring and improvement. However, both scoring systems were less accurate in predicting mortality for the older trauma patients and should be explored further.