Opioid Use and Fatal Motor Vehicle Crash Involvement: A Case-Control Study

Objective: Opioid use in the United States has increased markedly in the last two decades.   Epidemiologic evidence linking driver opioid use to crash risk is inconsistent. This population-based case-control study assessed the association of opioid use with fatal crash risk. Methods: Cases (n= 1841) were drivers involved in fatal motor vehicle crashes, identified from the 2006-2008 Fatality Analysis Reporting System, and controls (n= 7779) were a random sample of US drivers who participated in the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers.  Odds ratios (ORs) and 95% confidence intervals (CIs) of fatal crash involvement associated with opioid use were estimated through multivariable logistic regression.   Results: Overall, 4.0% of cases tested positive for opioids, compared with 2.3% of controls (p<.0001). Opioid use was associated with a 72% increased risk of fatal crash involvement (OR: 1.72; (95%CI: 1.31, 2.27)).  The estimated odds ratios of fatal crash involvement were 35.25 (95%CI: 18.66, 66.59) for drivers testing positive for both opioids and alcohol compared to those testing positive for neither substance, and 4.94; (95%CI: 2.70, 9.04) for drivers testing positive for both opioids and cannabis compared to those testing positive for neither substances. Conclusions: Use of opioids is associated with a significantly elevated risk of fatal crash involvement.  The risk of fatal crash involvement is exceptionally high for drivers who use opioids in combination of alcohol or cannabis.