Syncope and Traffic Crash: A Population-Based Case-Crossover Analysis.

BACKGROUND

Among individuals with recent syncope, recurrence of syncope while driving might incapacitate a driver and cause a motor vehicle crash. Current driving restrictions assume that some forms of syncope transiently increase crash risk. We evaluated whether syncope is associated with a transient increase in crash risk.

METHODS

We performed a case-crossover analysis of linked administrative health and driving data from British Columbia, Canada (2010 to 2015). We included licensed drivers who visited an emergency department with "syncope and collapse" and who were involved as a driver in an eligible motor vehicle crash, both within the study interval. Using conditional logistic regression, we compared the rate of emergency visits for syncope in the 28 days before crash (the "pre-crash interval") with the rate of emergency visits for syncope in 3 self-matched 28-day control intervals (ending 6, 12, and 18 months before the crash).

RESULTS

Among eligible crash-involved drivers, 47 of 3026 pre-crash intervals and 112 of 9078 control intervals had emergency visits for syncope, indicating syncope was not significantly associated with subsequent crash (1.6% vs 1.2%; adjusted odds ratio [OR], 1.27; 95% confidence interval [CI], 0.90-1.79; P = 0.18). There was no significant association between syncope and crash in subgroups at higher risk for adverse outcomes after syncope (eg, age > 65 years, cardiovascular disease, cardiac syncope).

CONCLUSIONS

In the context of prevailing modifications of driving behaviour after syncope, an emergency department visit for syncope did not transiently increase the risk of subsequent traffic collision. Overall crash risks after syncope appear to be adequately addressed by current driving restrictions.