The effects of alcohol on in-hospital mortality in drivers admitted after motor vehicle accidents.

BACKGROUND The effects of alcohol on morbidity and mortality following motor vehicle accidents (MVAs) are controversial. This study was performed to address the effect of alcohol on in-hospital mortality for drivers in MVAs admitted to a trauma center before and after controlling for injury severity, safety device use, and patient demographics. METHODS A retrospective study was performed using data from the National Trauma Data Bank, version 4.3. The cohort consisted of drivers in an MVA who were 15 years of age or older, had been admitted to the hospital on the same day as the accident, were screened for alcohol, and had no documentation of drugs in their system. Analyses were performed to explore the relationships between patient age, gender, race, presence of head injury, comorbid- ity status, injury severity score (ISS), and presence of alcohol and in-hospital mortality. RESULTS The cohort consisted of 67,021 patients, 38.3% of whom were drivers involved in an MVA and, following screening, were found to have alcohol present in their system. Drivers who had alcohol present were more likely to be younger, male, White, not using a safety device, and to have sustained a head injury, than drivers who had no alcohol present in their system (alcohol absent driv- ers) at hospital presentation. After controlling for potential confounding variables, risk factors for in-hospital mortality included male sex, older age, and higher injury severity, while protective factors included the presence of alcohol and use of safety devices. The single strongest predictor of mortality was ISS. Sensitivity analyses to relect the impact of inlation in true ISS scores in the subgroup of patients who had alcohol present as well as a head injury revealed that the protective effect of alcohol diminished and became nonsignificant when the ISS was reduced by 9% and became a significant risk factor for in-patient mortality when the false elevation in ISS was estimated at 21%. CONCLUSIONS These results suggest the importance of carefully considering the consequences that falsely inlated ISS scores might have for patients with alcohol present. Future work should evaluate the possible inlation of ISS and attempt to reconcile different interpreta- tions of the effects that the presence of alcohol may have on MVA mortality based by jointly considering crash site and in-hospital data.