Deriving injury severity from crash trauma data: RAPEX HARM from AIS 2015 coded injuries

The European Union's Safety Gate Rapid Alert System (RAPEX) notifies authorities of dangerous non-food products and mandates Hazard and Risk Assessment Methodology (HARM) evaluations that consider both acute injury severity and long-term consequences (LTC), defined as health effects persisting beyond the initial injury. The objective of this study is to develop a post-processing method that enables the direct use of Abbreviated Injury Scale (AIS) 2015-coded trauma data to compute RAPEX HARM assessments at the patient level.

Real-world crash data from the German in-depth Accident Study (GIDAS) database, spanning 1999 to 2024, were analyzed. The AIS 2015 codebook provides two injury metrics per injury: the AIS Code (AIS-CD), which quantifies acute threat to life, and the predicted Functional Capacity Index (pFCI), which assesses long-term incapacitation. To address coding variability and misalignment between the AIS-codebook with clinical diagnoses, the original 6-digit AIS unique identifiers (AIS-IDs), which specify injury type, location, and severity, were aggregated to a more robust level of detail. Subsequently, individual injury severities were summarized at the person level using a conversion based on the three most severe injuries (triples), analogous to the New Injury Severity Score (NISS). The HARM Level (1-4) assigned to each patient reflects the most severe outcome, determined independently from either the AIS-CD or pFCI injury triple conversion.

The AIS-CD, representing an acute threat to life, was the primary determinant of lower HARM scores, whereas the LTC metric became increasingly influential at higher HARM severities. At the highest severity level (HARM 4), AIS-CD was the dominant factor in 53% of cases, pFCI (long-term disability metric) in 16%, and both metrics were equally severe in 31% of cases.

The proposed post-processing method assigns RAPEX HARM values to patients with AIS 2015-coded injuries by using both acute threats to life (AIS-CD) and long-term consequences information (pFCI), enabling RAPEX evaluations of crash and trauma databases.