Biases in the collection of blood alcohol data for adult major trauma patients in Victoria, Australia

In-hospital alcohol testing provides an opportunity to implement prevention strategies for patients with high risk of experiencing repeated alcohol-related injuries. However, barriers to alcohol testing in emergency settings can prevent patients from being tested. In this study, we aimed to understand potential biases in current data on the completion of blood alcohol tests for major trauma patients at hospitals in Victoria, Australia.Victorian State Trauma Registry data on all adult major trauma patients from 1 January 2018 to 31 December 2021 were used. Characteristics associated with having a blood alcohol test recorded in the registry were assessed using logistic regression models.This study included 14 221 major trauma patients, of which 4563 (32.1%) had a blood alcohol test recorded. Having a blood alcohol test completed was significantly associated with age, socioeconomic disadvantage level, preferred language, having pre-existing mental health or substance use conditions, smoking status, presenting during times associated with heavy community alcohol consumption, injury cause and intent, and Glasgow Coma Scale scores (p<0.05). Restricting analyses to patients from a trauma centre where blood alcohol testing was part of routine clinical care mitigated most biases. However, relative to patients injured while driving a motor vehicle/motorcycle, lower odds of testing were still observed for patients with injuries from flames/scalds/contact burns (adjusted OR (aOR)=0.33, 95% CI 0.18 to 0.61) and low falls (aOR=0.17, 95% CI 0.12 to 0.25). Higher odds of testing were associated with pre-existing mental health (aOR=1.39, 95% CI 1.02 to 1.89) or substance use conditions (aOR=2.33, 95% CI to 1.47-3.70), and living in a more disadvantaged area (most disadvantaged quintile relative to least disadvantaged quintile: aOR=2.30, 95% CI 1.52 to 3.48).Biases in the collection of blood alcohol data likely impact the surveillance of alcohol-related injuries. Routine alcohol testing after major trauma is needed to accurately inform epidemiology and the subsequent implementation of strategies for reducing alcohol-related injuries.