The effect of socioeconomic status on severe traumatic injury: a statistical analysis

Purpose: The amount of studies performed regarding a link between socioeconomic status (SES) and fatal outcome after traumatic injury is limited. Most research is focused on work-related injuries without taking other important characteristics into account. The aim of this study is to examine the association between SES and outcome after traumatic injury. Methods: The study involved polytrauma patients [Injury Severity Score (ISS) ≥ 16] admitted to the Amsterdam University Medical Center (location VUmc) and Northwest Clinics Alkmaar (level 1 trauma centers). The SES of every patient was based on their postal code and represented with a “status score”. Univariate and multivariable analyses were performed to estimate the association between SES and mortality, length of stay at the hospital and length of stay at the Intensive Care Unit (ICU). Z-statistics were used to determine the difference between the expected and actual survival, based on Trauma Revised Injury Severity Score (TRISS) and PSNL15 (probability of survival based on the Dutch population). Results: A total of 967 patients were included in this study. The lowest SES group was significantly associated with more penetrating injuries and a younger age (45 years versus 55 years). Additionally, severely injured patients with lower SES were noted to have a prolonged stay at the ICU. Furthermore, differences were found in the expected and observed survival, especially for the lower SES groups. Conclusion: Polytrauma patients with lower SES have more often penetrating injuries, are younger and have a longer stay at the ICU. No association was found between SES and length of hospital stay and neither between SES and mortality