Prescription medicine use by pedestrians and the risk of injurious road traffic crashes: A case-crossover study

Abstract

Background

While some medicinal drugs have been found to affect driving ability, no study has investigated whether a relationship exists between these medicines and crashes involving pedestrians. The aim of this study was to explore the association between the use of medicinal drugs and the risk of being involved in a road traffic crash as a pedestrian.

Methods and findings

Data from 3 French nationwide databases were matched. We used the case-crossover design to control for time-invariant factors by using each case as its own control. To perform multivariable analysis and limit false-positive results, we implemented a bootstrap version of Lasso. To avoid the effect of unmeasured time-varying factors, we varied the length of the washout period from 30 to 119 days before the crash. The matching procedure led to the inclusion of 16,458 pedestrians involved in an injurious road traffic crash from 1 July 2005 to 31 December 2011. We found 48 medicine classes with a positive association with the risk of crash, with median odds ratios ranging from 1.12 to 2.98. Among these, benzodiazepines and benzodiazepine-related drugs, antihistamines, and anti-inflammatory and antirheumatic drugs were among the 10 medicines most consumed by the 16,458 pedestrians. Study limitations included slight overrepresentation of pedestrians injured in more severe crashes, lack of information about self-medication and the use of over-the-counter drugs, and lack of data on amount of walking.

Conclusions

Therapeutic classes already identified as impacting the ability to drive, such as benzodiazepines and antihistamines, are also associated with an increased risk of pedestrians being involved in a road traffic crash. This study on pedestrians highlights the necessity of improving awareness of the effect of these medicines on this category of road user.

Abstract

In a case-crossover study, Mélanie Née and colleagues examines the association between use of presciption medicine by pedestrians and risk of injurious road traffic crashes.

Author summary

Why was this study done?

• Pedestrians account for 22% of the world’s road traffic deaths.

• Medicines have the potential to impair the ability of all road users, including pedestrians.

• To our knowledge, no study so far has investigated the association between consumption of medicinal drugs and risk of road traffic injury as a pedestrian.

What did the researchers do and find?

• We matched French nationwide databases with data on road traffic crashes (collected by police officers) and data on medicine delivery (collected by the national healthcare insurance system).

• We identified 16,458 pedestrians involved in an injurious road traffic crash between 1 July 2005 and 31 December 2011. Among them, 6,584 were included in our analyses.

• Several classes of medicine were associated with an increased risk of a pedestrian being involved in a road traffic crash.

• The most commonly consumed medicines associated with an increased risk of crash included benzodiazepines and benzodiazepine-related drugs, antihistamines, and anti-inflammatory and antirheumatic drugs.

What do these findings mean?

• Increased awareness of the risks of medicine use for pedestrians is important as the risks of medicines in road safety have hitherto been thought to concern drivers only.