Prescription medications and motor vehicle crash risk
Objective 1: To identify medication users with elevated crash rates.
Research question 1.1
i) Which classes of medications are associated with an increased risk of crashing in new users?
ii) How does this risk vary with time from start of first prescription?
Research question 1.2:
Which classes of medications are used more often by drivers found responsible for causing a crash compared to non-responsible drivers?
Objective 2: To identify classes of medications which trigger motor vehicle crashes.
Research question 2:
i) Which classes of medications are used more commonly by crash involved drivers immediately before the crash compared to the same time 4 weeks or 8 weeks ago (control periods)?
ii) Which classes of medications are used more commonly by responsible (culpable) drivers immediately before the crash compared to during the control periods?
Our analysis plan is to test (and hopefully disprove) the null hypothesis for each class of medications (ie that there is not an association between medications and crash risk).
We suspect that some classes of medications (for example benzodiazepines, other sedatives, antidepressants, opioids) will be associated with increased crash risk. Expressing this in terms of our research questions, we suspect that:
1.1 i) New users of benzodiazepines will have an increased risk of crashing.
1.1 ii) Crash risk will be highest in the first few weeks of a new prescription for benzodiazepines
1.2 drivers involved in a crash who use benzodiazepines are more likely to be responsible for the crash than drivers involved in a crash who do not use benzodiazepines. will be more likely to use benzodiazepines than drivers not deemed responsible,
2 i) Drivers involved in a crash are more likely to have an active prescription for benzodiazepines immediately prior to the crash than during control periods chosen 4 and 8 weeks prior to the crash.
2 ii) Drivers responsible for a crash are more likely to have an active prescription for benzodiazepines immediately prior to the crash than during control periods chosen 4 and 8 weeks prior to the crash.