Association between socioeconomic and geographical factors in severely injured trauma patients using trauma registry data

Abstract

Background: Injuries remain a significant cause of premature death, morbidity and disability in Australia, and include a disproportionate number of people who are socioeconomically disadvantaged. A mix of economic, social, physical, and environmental factors defines a person’s socioeconomic status and can influence an individual’s injury risk behaviours, employment, education and ability to access to services. The positive gradient between rurality and socioeconomic disadvantage in Australia is well recognised yet has not been well described for trauma populations. As time to definitive trauma care is associated with major trauma outcomes, geographical factors could confound studies of social disadvantage and trauma occurrence. This study aimed to describe the relationship between neighbourhood socioeconomic disadvantage and geographic remoteness on injury patterns, including injury severity and pre-tertiary management of patients admitted to a Level 1 Metropolitan Trauma Centre in Queensland, Australia, between 2014 to 2017.

Methods: A cross-sectional study was conducted of adults hospitalised in a Level 1 Trauma Centre who met criteria for major trauma. Area-level explanatory variables included the Index of Relative Socioeconomic Disadvantage, and the Australian Standard Geographical System (ASGS) remoteness structure. These were linked to patient variables, which included age, injury severity, number of comorbidities, injury mechanism, postcode of injury occurrence, and the first provider of care.

Results: 1025 patients were available for analysis, of which 77% were male. The mean age was 45 (SD 19.46) and median ISS was 17 (IQR=12). Increasing relative socioeconomic disadvantage was statistically significantly, and positively associated with remoteness of residence (X2=41.61, p<0.001) remoteness of injury location (X2=19.73, p<0.001), and number of comorbidities (KW H Statistic=11.26, p=0.01). Of those who received initial care from a regional hospital, there is a significant and positive trend according to increased likelihood of being disadvantaged category compared with those treated at the major trauma centre. (X2=14.14, p=0.003). After adjusting for age, sex, injury severity and remoteness of injury location, a positive gradient of increasing disadvantage according to geographical remoteness of residence was evident, with a sixfold increase in the odds of being in the most disadvantaged category, compared to the least disadvantaged (OR 6.21, 95% CI 3.07-12.57, p<0.001). Conclusions Robust socio-ecological measures linked to a Trauma Registry can enable examination of contextual factors associated with injury patterns and early management. Geographical factors related to rurality of residence and regional trauma care are positively associated with neighbourhood socioeconomic disadvantage and should be considered when designing epidemiological studies of disparities in injury risk or injury outcomes.