Alcohol effects on motor vehicle crash injury
Authors: Patricia F. Waller, Frederic C. Blow, Ronald F. Maio, Elizabeth M. Hill
Context: Although alcohol is frequently present in injured patients, whether it exacerbates injury and whether tolerance to alcohol changes such a relationship is less clear. Most clinical studies do not consider other important predictors of injury, making interpretation of their findings problematic. Objective: To examine alcohol's role in injuries, taking into account other important factors, and to examine the effect of tolerance, if any. Design: Prospective cohort study. Setting: University hospital and community hospital emergency departments and morgue. Patients: 1362 Motor Vehicle Crash patients age ≥18, treated and released, admitted, and deceased. Main Outcome Measures: Excess injury measured by Injury Severity Scale (ISS) 90, Weighted Revised Trauma Score (WRTS), and G-Score. Results: Using regression analysis, the best predictors of injury severity were vehicle crush (TAD), safety belt use, and their interaction, and age. Alcohol use further predicted injury. Using the final regression model, the effect of alcohol was to increase ISS90, on average, by about 30% (from a predicted ISS90 of 5.1 to 6.8, all else being equal). The adjusted odds ratio for serious injury (ISS90>15), was 1.59 for a patient with a positive blood alcohol concentration (alc+) compared to a alc− patient. This potentiating effect is seen even for patients with low levels of alcohol (<22mmol/liter; <0.100 BAC) but is not linear with increasing alcohol level. Tolerance to alcohol did not affect the potentiation of injury by alcohol. Conclusion: When other relevant variables are considered, alcohol increases injury, but the effects of alcohol level and alcohol tolerance are less clear. These findings have important implications for injury prevention, treatment, and research.